Learn how to wake up a BMS that has went into safe or sleep mode. Simple to follow to within. 

How to Wake Up a BMS in Sleep or Safe Mode

For various reasons, a perfectly good lithium ion battery can end up in sleep mode, so it’s important to know how to wake up a BMS. A BMS can go into sleep or safe mode due to a variety of circumstances. When this happens, it can be a major pain to deal with and it can make a battery seem like it’s broken.&nbsp;Best case scenario, all you will have to do is detach and reattach the load from the battery to wake up a BMS. This, however, will only work if your BMS has auto-recovery. If that doesn't work, you can try to put your battery on a charger for a moment. That’s all it will take to determine if a non auto recovering BMS is in sleep mode, and it’s the only way to wake up a BMS if it is.&nbsp;If your BMS does not have auto recovery and you are stranded outside with nowhere to charge your battery, then you can try to jump start the BMS by shorting the B- and P- connections. It works on almost all BMS, and the good news is that it will either work or not, it won’t break anything. The bad news is that the B- connection can be pretty hard to get to.&nbsp;In this article, we will cover several ways that a BMS can go into sleep, and we will explain several methods that can be used to wake up a BMS.&nbsp;<h2>Why Does A BMS Go Into Sleep or Safe Mode?</h2>There are several reasons a BMS would end up in protection mode and sleep mode is basically an extended version of protection mode. For example, when a lithium-ion battery is at around 30 percent capacity and is then put under a sudden, high load, the battery cells can momentarily dip below the LVC (Low Voltage Cutoff).This will cause the battery to shut off (put into protection mode) to protect the cells This can make it seem like the battery is damaged because it can happen when the battery is still pretty full.&nbsp;Another way a BMS can be into protection mode is if it is shorted out or overloaded. When a short or overload occurs, the amount of amps that flows through the BMS can be tremendous. Luckily there is high speed circuitry on the BMS that shuts things down when this type of fault condition is detected.&nbsp; For a BMS to go into sleep mode, the cell groups generally have to fall well below the LVC (Low Voltage Cutoff) point. This can happen when the battery is stored and not used for an extended period of time. In this case, the cell groups need to be individually charged directly, rather than through the BMS in series. This is not advisable to do if the cells are lower than 2 volts. However, if you find yourself with cells below 2v we wrote a guide on <a href="https://cellsaviors.com/blog/recover-low-voltage-cells-batteries">how to revive low-voltage cells</a>.&nbsp;<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/jpeg&quot;,&quot;filename&quot;:&quot;BMS that went into safe mode.jpg&quot;,&quot;filesize&quot;:28722,&quot;height&quot;:321,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/YKoc4lWGwFwiJiY2WgkWwBan9uXaDLH0NgjcC7wl.jpg&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/YKoc4lWGwFwiJiY2WgkWwBan9uXaDLH0NgjcC7wl.jpg&quot;,&quot;width&quot;:295}" data-trix-content-type="image/jpeg" data-trix-attributes="{&quot;presentation&quot;:&quot;gallery&quot;}" class="attachment attachment--preview attachment--jpg"><a href="https://admin.cellsaviors.com/storage/YKoc4lWGwFwiJiY2WgkWwBan9uXaDLH0NgjcC7wl.jpg"><img src="https://admin.cellsaviors.com/storage/YKoc4lWGwFwiJiY2WgkWwBan9uXaDLH0NgjcC7wl.jpg" width="295" height="321"><figcaption class="attachment__caption">BMS that went into safe mode.jpg 28.05 KB</figcaption></a></figure><h2>Try Removing The Load to Get The BMS Out Of Safe Mode</h2>You might just get lucky and have an auto-recovering BMS. It does not require an expensive BMS to have auto-recovery. In fact, some expensive BMS don’t have it. It’s less of a feature and more of a design choice. For some loads, it's reasonable for the BMS to recover on its own and the device resumes operation as normal.&nbsp;With other loads, it can be dangerous for the device to suddenly spring back to life after a loss of power. So if you are riding your ebike and you hit a steep hill and lose power, but you know your battery is not dead yet, simply try to unplug the battery from the controller and plug it back in.&nbsp;In many cases, that will turn the BMS right back on and you will be able to carefully make it home. This time, just make sure to take it easy on the hills so that your battery cell groups don’t end up hitting the Low Voltage Cutoff point. &nbsp;For BMS that support auto-recovery, there is a range of when it will recover. Some will require the load to be completely removed from the BMS, and others only require the current to fall back down below a given threshold.For the second type, the recovery is truly automatic. If you have an ebike that has ever totally cut out and then started working again without you having to do anything, then it is more than likely a current-triggered auto-recovering BMS.&nbsp;<h2>How to Use a Charger to Wake Up a BMS</h2>If a BMS does not support auto-recovery, then the only other official way to wake up a BMS is to place it on a charger. Being required to be attached to a charger for the BMS to wake up is the safest way to operate a lithium-ion battery. It means that the load wont randomly turn back on, and it means that the battery cells will for sure no not be put under a load that will damage the cells.&nbsp;So, if removing and reattaching the load doesn’t do the trick, simply attach a battery charger for like 0.2 seconds. The reason I say to do it quickly is to find out if the battery is in protection mode, sleep mode, or just dead. If you put it on the charger for an extended period of time before checking, then you won't know if it was just dead and needed to charge or if the BMS was tripped, and it's good to know.&nbsp;Surprisingly when using a charger to wake up a BMS using a <a href="https://cellsaviors.com/blog/lithium-charger-diy">DIY charger</a> may be a better option so you can monitor if the pack is accepting the charge or now.After briefly connecting the battery to a charger, check for voltage at the discharge connector with a multimeter or just hook the battery back up to the load and see if it comes on. If it does, then your battery is probably full and you simply have a BMS that does not support auto-recovery.&nbsp;<h2>Jump-Starting A BMS To Wake It Up</h2>Jump-starting the BMS is a process that can be used to revive a lithium-ion battery pack that has a 0V output. According to the information above, this process can be done in cases where the BMS has tripped and is preventing the battery from functioning normally.To jump-start the BMS, you need to short the B- and P- connections on the BMS. This can be done using a metal wire or any other conductive material. First, locate the B- and P- connections on the BMS. They are usually marked on the circuit board or can be found in the wiring diagram for the battery pack.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/jpeg&quot;,&quot;filename&quot;:&quot;BMS B- and P- connection location.jpg&quot;,&quot;filesize&quot;:73545,&quot;height&quot;:252,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/C374kHbYcEBs9HIeE8PmcaZ42BqFDpaCTDD8eKeP.jpg&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/C374kHbYcEBs9HIeE8PmcaZ42BqFDpaCTDD8eKeP.jpg&quot;,&quot;width&quot;:498}" data-trix-content-type="image/jpeg" data-trix-attributes="{&quot;presentation&quot;:&quot;gallery&quot;}" class="attachment attachment--preview attachment--jpg"><a href="https://admin.cellsaviors.com/storage/C374kHbYcEBs9HIeE8PmcaZ42BqFDpaCTDD8eKeP.jpg"><img src="https://admin.cellsaviors.com/storage/C374kHbYcEBs9HIeE8PmcaZ42BqFDpaCTDD8eKeP.jpg" width="498" height="252"><figcaption class="attachment__caption">BMS B- and P- connection location.jpg 71.82 KB</figcaption></a></figure>Once you have located the connections, carefully touch the metal wire or other conductive material to both connections at the same time. Hold the wire in place for a moment, just a fraction of a second. This will trick the BMS into thinking it's connected to a charger. After that, remove the wire and place the battery on a charger.If it works, the BMS should wake up and return to normal, enabling the battery pack’s discharge connection to show a voltage on the output.&nbsp; It's important to note that jumping starting the BMS should only be done if you definitely know what you are doing. If you touch the wrong thing to the wrong place, it could be a very bad day.&nbsp;<h2>Bypassing the BMS to Get A Battery Out of Protection Mode</h2>In some cases, a perfectly good battery could have its voltage fall past a critical threshold that puts the BMS into sleep mode. There are many types of BMS and they all have different features and governing principles. Generally speaking, however, most BMS will completely disable the battery (go into protection mode) if the cells fall below around 2.4 volts or so.&nbsp;Once this happens, both charging and discharging is disabled. The only way to solve this is to access the individual cell groups and charge them to within range of the BMS. Like I said, all BMS are different, but generally speaking, if you can bring the cell groups up past 2.5 volts or so, the BMS will come out of sleep mode.&nbsp;This can be done by attaching a constant current power supply to each cell group, one at a time. The voltage of the power supply should be set to about half a volt higher than the target cell’s voltage. The current should be set very low, to around 250ma at first.&nbsp;Once the cell fully charges to a half a volte higher than it was, change the settings on the power supply to make it 1 volt higher than the cell’s new voltage, and this time set the current half an amp. If the cell groups respond well to this pattern and don’t get alarmingly hot while you are charging them, then chances are, you will be able to wake up the BMS.&nbsp;<blockquote>[[ aff type=cta ~ bg=`` ~ main=`Guided BMS Picker` ~ second=`If non of these methods work it may be time for a new BMS, use the tool found at the link below to get guided to the correct BMS. ` ~ btnText=`BMS Picker` ~ btnLink=`https://cellsaviors.com/bms-picker` ~ align=`center` ]]</blockquote><h3>Conclusion</h3>Waking up a BMS that has stopped functioning normally requires proper knowledge and techniques to avoid any potential danger, but if you know what to do, you can do it!The easiest to deal with method is to remove and reattach the load from the battery. This will only work if your BMS supports auto-recovery, but a surprising amount of them do. If that doesn't work, you can try to put your battery on a charger for a brief period of time. This will help you determine if the battery is simply dead or if the BMS is either in sleep mode, protection mode, or the battery is simply dead.&nbsp;If your BMS does not support auto recovery and you are in a situation where there is no way you can connect your battery to a charger, then you can jump-start the BMS by shorting the B- and P- connections. It works on almost all BMS, and the good news is that it will either work or not. Nothing bad will happen and no damage will be done.We hope this article helped you learn everything you needed to know about how to wake up a BMS, thanks for reading!

How to Wake Up a BMS

Comparing AGM batteries to lithium batteries can help pick which is best for your needs, read more here!

AGM Battery Vs Lithium Ion Battery

AGM vs Lithium, which one is best? If you are new to lithium-ion batteries or just batteries in general, then it is totally normal to wonder which one of these battery technologies are the right way to go. After learning a bit about the differences between AGM and lithium batteries, we are confident that it will become clear that lithium is the better choice for most applications.&nbsp;Lithium batteries are smaller, more energy dense, have a longer lifespan, can charge much faster, have a wide operating temperature, and have a lower self discharge rate. It’s not all sunshine and rainbows, as there are some downsides to lithium. Lithium batteries have a higher initial cost than AGM batteries, and they require a specialized charging system that must not only be compatible with lithium batteries, but it must also be compatible with your lithium battery’s particular cell chemistry. Lithium batteries have earned somewhat of a dangerous reputation. Many lithium-ion batteries have caught fire and even exploded. It is important to keep in mind that these cases always require several best-practice rules to be broken in the design, construction, and use phases for this to happen.&nbsp;AGM and other lead acid batteries have a lower upfront cost. These types of batteries have been in production for quite some time, so you can find them everywhere. Lead acid batteries have to be heavy, large structures to work well, so you won’t find any tiny lead acid batteries that are not capable of running high currents- they generally all can. Another benefit of this older type of battery is that no special charging equipment is needed. All you have to do is give the battery a voltage that is higher than the battery voltage but within its tolerable range and it will charge. AGM batteries are, however, much heavier and larger than a lithium battery of the same capacity. Also, they have a shorter lifespan which means you will have to replace them sooner. Another super important thing to remember is that AGM batteries have only a maximum 80% depth of discharge. This means that you can only use 80 percent of the energy contained within them before you begin damaging the cells. Another glaring problem with AGM is that it has a higher self-discharge rate than lithium.&nbsp;In this article, we will compare and contrast AGM vs Lithium batteries. We will explain the pros and cons of each battery technology, and go over some use cases where each one is best. Knowing all of this information will be especially helpful if you are looking to <a href="https://cellsaviors.com/blog/lead-acid-agm-lithium-replacement">convert something from lead acid to lithium</a>.<h2>Comparison of AGM and Lithium Battery Characteristics</h2><h3>Lithium Batteries</h3>Pros:<ul><li>Lightweight and compact</li><li>High energy density</li><li>Longer lifespan</li><li>Fast charging capabilities</li><li>Wide operating temperature range</li><li>Low self-discharge rate</li></ul>Cons:<ul><li>Higher upfront cost compared to AGM or lead acid batteries</li><li>Specialized CC/CV (Constant Current/Constant Voltage) charger required</li><li>Potential safety concerns if damaged or improperly designed or used</li><li>Limited availability in some regions</li></ul><h3>AGM / Lead Acid Batteries</h3>Pros:<ul><li>Lower upfront cost compared to lithium batteries</li><li>Widely available</li><li>More robust and durable than lithium batteries</li><li>No special charging equipment required</li></ul>Cons:<ul><li>Far heavier and much larger than lithium batteries</li><li>Lower energy density compared to lithium batteries</li><li>Shorter lifespan compared to lithium batteries</li><li>Slower charging capabilities compared to lithium batteries</li><li>Higher self-discharge rate compared to lithium batteries</li><li>Higher TCO (Total Cost of Ownership)</li></ul> <h2>AGM vs Lithium - Capacity and Power Output</h2>When it comes to choosing between AGM (Absorbed Glass Mat) and lithium batteries, capacity and power output are two of the most important factors. AGM batteries typically have a capacity of around 50-200Ah, which is sufficient for many uses such as powering RVs, boats, and backup power systems.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image&quot;,&quot;height&quot;:341,&quot;url&quot;:&quot;https://lh3.googleusercontent.com/tU8sKoq9OUilo7oQ3N8LA_r4EoHfeJ5FH-7GS47ZX-Q8InhqRBy4Wf82PI2M7bhqhOHGoOTbUkZh-4R4BMq6MTXLSlNqrpT2TPONp_472JGtixLk3Z-qNB1ndOmZmFUg9aNuC6vt7dPEhWgB7wY4UBw&quot;,&quot;width&quot;:624}" data-trix-content-type="image" class="attachment attachment--preview"><img src="https://lh3.googleusercontent.com/tU8sKoq9OUilo7oQ3N8LA_r4EoHfeJ5FH-7GS47ZX-Q8InhqRBy4Wf82PI2M7bhqhOHGoOTbUkZh-4R4BMq6MTXLSlNqrpT2TPONp_472JGtixLk3Z-qNB1ndOmZmFUg9aNuC6vt7dPEhWgB7wY4UBw" width="624" height="341"><figcaption class="attachment__caption"></figcaption></figure>AGM and other lead acid batteries have a relatively low specific energy of around 80 to 90 Wh/L (Watt Hours per Liter). A standard NMC lithium-ion battery will have a specific energy of somewhere between 150 and 200 Wh/L which is much higher than lead acid and its variants. LiFePO4 lithium batteries have a <a href="https://ecotreelithium.co.uk/news/lifepo4-vs-lithium-ion-batteries/">specific energy of around&nbsp;90 to 165 Wh/L</a>, which is less than NMC lithium-ion, but still a much higher overall specific energy than lead acid. This means that lithium batteries can store more energy than a lead acid or AGM battery while using the same amount of space.&nbsp;When it comes to power output, AGM batteries are great at delivering high current for short periods of time but are not so great at delivering a consistent amount of power for a long period of time. For this reason, lead acid batteries are still suitable for applications that require high peak power in short bursts. In contrast, Lithium batteries are capable of delivering both a high amount of power burst and also a highly consistent energy capability. The problem is that lithium-ion batteries are much more expensive.&nbsp;In almost all cases, lithium will be a better choice. While it is true that both types of batteries have their strengths and weaknesses, lithium ion’s increased performance, power density, charging speed, and lifespan make it the overall lower-cost option that has the most benefits.&nbsp;<h2>Lifespan and Durability of AGM vs Lithium</h2>In terms of lifespan and durability of AGM vs lithium, it depends on the use case. AGM batteries are known for their robust and durable nature, but they have an older, much more inefficient cell chemistry. This makes them great for applications that require high discharge currents for short periods of time, but not so great at providing long run times compared to a lithium battery of the same physical size. Another good point for AGM durability is the fact that they are relatively resistant to damage from overcharging, over-discharging, and vibration, and require no specialized charging circuitry.&nbsp; This makes AGM batteries more suitable for harsh conditions.While it is true that lithium-ion batteries are more sensitive to the environment and electrical infrastructure, they have a much longer lifespan compared to AGM batteries when properly cared for. In fact, lithium batteries can last up to three times longer than AGM batteries of the same capacity. This, as you may expect, results in significant cost savings over the long term. You can get even more<a href="https://cellsaviors.com/blog/get-more-cycles-from-lithium-ion-cells"> cycles and life out of lithium batteries</a> by following certain rules.Another important thing to keep in mind is that while a raw lithium battery is more sensitive to damage from overcharging, over-discharging, and high temperatures compared to AGM batteries, <a href="https://cellsaviors.com/blog/bms-lithium-batteries">having the right BMS</a> almost entirely solves all of these problems.So, AGM vs lithium, which is the most durable? Both battery types have their strengths and weaknesses but lithium-ion will generally be the better choice unless initial cost is a huge driving factor.&nbsp;<h2>The Charging and Maintenance Requirements of AGM Compared To Lithium</h2>The charging and maintenance requirements of AGM and lithium batteries are important factors to consider when choosing between these two types of batteries.AGM batteries are relatively low maintenance in terms of their charging and discharging, with most models requiring little to no maintenance. AGM batteries can be charged using regular, ordinary battery chargers and power supplies and don’t require any special equipment or BMS.&nbsp;Lithium batteries, on the other hand, require specialized charging equipment and can be more sensitive to overcharging and over-discharging compared to AGM batteries, so they absolutely require a BMS. A BMS is a critical, required component of lithium-ion batteries as it monitors the battery's state of charge and protects it from damage during charging and discharging.While AGM batteries require little-to-no maintenance, lithium batteries require absolutely no maintenance. As long as a lithium-ion battery is used properly, it will have a much longer lifespan. If a lithium battery has a BMS (and every lithium-ion battery should), then a lithium battery is less susceptible to degradation over time compared to AGM. This nets a more consistent performance over the life of the battery.<h2>AGM vs Lithium Cost Comparison</h2>Cost is a major consideration when it comes to choosing between AGM and lithium batteries. AGM batteries are typically more affordable upfront, making them a popular choice for those who are on a tight budget. However, while AGM batteries may have a lower upfront cost, they have a shorter lifespan, which means you will need to replace them more frequently. This can quickly add up and offset any savings from the lower upfront cost.Lithium batteries, on the other hand, have a higher initial cost, but their longer lifespan and superior performance make them a smart investment in the long run. Also, lithium batteries are smaller, more energy dense, can charge much faster, have a wide operating temperature, and have a remarkably low discharge rate.So when it comes to AGM vs lithium, lithium is the clear winner in this regard. Because of these characteristics, lithium batteries are ideal for applications where space and weight are at a premium, such as in electric vehicles and portable consumer electronics. The longer lifespan of lithium batteries also means that you will not need to replace them as frequently, which can help to lower the total cost of ownership over time.While the higher initial cost of lithium batteries may seem overwhelming at first calculation, it is important to consider the total cost of ownership (TCO) when making any buying decision. When you take into account the longer lifespan, superior performance, and reduced replacement costs, lithium batteries often have a lower TCO than AGM batteries.In fact, the TCO of lithium batteries can be much lower, making them a more cost-effective option in a much shorter time span than you may expect. This is a running them across many industries and product segments, so remember to look beyond the upfront cost and consider the long-term implications before you make any major purchase.<h2>Environmental Impact of AGM and Lithium Batteries</h2>AGM batteries, also known as lead-acid batteries, have been around for over a century and are made from materials that are widely available and easily recyclable. Lead is, however, a toxic material that can have serious environmental consequences if not properly disposed of. Lead is a cumulative poison in the body, which means that once it gets in there it doesn’t come out. If lead leaches into the soil and groundwater, it can cause long-term damage to the environment. In addition, the production of AGM batteries generates significant amounts of waste, including lead, sulfuric acid, and other toxic materials.Lithium batteries themselves, on the other hand, are much more environmentally friendly. They are made from materials that are widely available and are known to be non-toxic, and their production generates much less waste compared to AGM batteries.&nbsp;The problem with lithium recycling is that it requires extremely expensive specialized equipment to extract the valuable material used to make the cell. It’s not something that is commonly done yet, so most lithium-ion batteries are wasted once they reach their end of life. On the other hand, lithium batteries can contain cells that are perfectly fine to reuse. Most packs will have one or more cells go bad leaving many more available for reuse. This has led to people <a href="https://cellsaviors.com/blog/how-to-salvage-18650-cells">salvaging thrown-out lithium battery packs</a> for reuse.&nbsp;Another important thing to consider in regards to environmental impact is the weight of transport. Lithium batteries are lighter and smaller than AGM batteries, which makes them more energy-efficient to transport, which reduces their overall carbon footprint.<h2>When To Use AGM vs Lithium Batteries</h2><h3>Use an AGM battery for:</h3><ul><li>Backup power systems</li><li>Applications that require a wide operating temperature range</li><li>Standby power for essential services</li><li>Applications that require a reliable source of power for short periods of time</li></ul><h3>Use a Lithium battery for:</h3><ul><li>Electric vehicles and other high-performance applications</li><li>Portable devices, such as laptops and smartphones</li><li>Applications that require fast recharge times</li><li>Applications that require high energy density</li><li>Applications that require a long lifespan.</li></ul><h2>When To Not Use AGM vs Lithium Batteries</h2><h3>Don't use an AGM battery with:</h3><ul><li>Applications that require fast recharge times</li><li>Applications that require high energy density</li><li>Applications that require a long lifespan</li></ul><h3>Don't use a Lithium battery with:</h3><ul><li>Applications that require an extremely low upfront cost</li></ul><h3>Conclusion: Choosing the Right Battery for Your Needs.</h3>After considering the differences between AGM and lithium batteries, it becomes clear that lithium is the more suitable option for the majority of applications. The compact size, high energy density, long lifespan, and fast charging time put lithium batteries leagues above their AGM counterparts. Despite the drawbacks of lithium batteries, such as their higher initial cost and the requirement for specialized charging equipment, these benefits make them a superior choice in almost all circumstances.One of the major advantages of lithium batteries is their high energy density, which enables extremely compact batteries. This makes them ideal for applications where space is limited. Batteries are, in general, used in portable devices where weight and space are at a premium such as in electric vehicles and portable consumer electronics. Another massive benefit of lithium-ion batteries is that they have a substantially longer lifespan than AGM batteries, which means you will have to come up with the cash to replace them a lot less frequently.AGM batteries, however, do have some advantages over lithium-ion batteries and are better in some extremely limited use cases. For example, if you need to perform high-current, short-acting operations and are only using the batteries as a current buffer rather than a means of energy storage, then AGM batteries can be the more practical option if the cost or availability of lithium-ion is an issue. It’s important to keep in mind that despite the higher initial cost of lithium batteries, they are worth the investment due to their many benefits and actually have a lower TCO (Total Cost of Ownership). We hope this article helped you learn everything that you needed to know about AGM vs Lithium, thanks for reading!

AGM vs Lithium

Looking to make your ebike run off of two batteries? We put together this easy to follow guide so you can get it done! 

How To Add Dual Batteries To Your Ebike

If you have an ebike and have been wanting more range or speed, you might be wondering how to install dual batteries on your ebike. There are a couple of ways this can be done and some are more viable than others.&nbsp;When connecting dual ebikes in series, you have to connect the positive of the first battery to the negative of the second battery. After that, connect the remaining free positive and negative connections to the ebike speed controller. All ebike batteries should have a BMS, and problems can arise when running 2 ebike batteries in series. This is because the MOSFETs in the BMS are not going to be rated for the full battery voltage of both packs. Under normal operation, this is not a problem as the voltage across the MOSFETs on both battery packs is close to zero. When one battery dies, however, its MOSFETs will switch into a high resistance state. When this happens, those MOSFETs will experience the voltage of the still working battery and the voltage of the dead cells in the dead battery. In most cases, this will overvolt the MOSFETs in the BMS of the dead battery.When connecting dual ebike batteries in parallel, you have to connect the positive from the first battery to the positive of the second battery. After that, you can connect the speed controller to either battery. It’s important for the batteries to be at the same voltage before connecting them. If they are not, then a large amount of current will flow from the higher voltage battery to the lower voltage battery. Even if the batteries are at the same voltage when you connect them and everything seems to work fine, its not good to put two batteries of different capacities in parallel. This causes the batteries to be in an imbalanced state of discharge and makes it so the larger battery is always charging the smaller battery at an unpredictable rate. This puts extra strain on everything and reduces the life of the batteries. People usually don't notice because there is still a net gain in capacity from adding the second battery, but it's really reducing the overall life of the system.&nbsp;In this article, we will go over how to install dual batteries on an ebike. We will also explain the pros and cons for each setup, and when to not do each one.&nbsp;<h2>Installing Dual Batteries In Series</h2>So, a lot of people are wanting to know if it’s possible to wire 2 36V ebike <a href="https://cellsaviors.com/blog/series-lithium-batteries">batteries in series</a> to make a 72V battery. Wiring up two batteries to make a 72V setup is technically possible, but it is not recommended. The main concern is the Battery Management System (BMS) and what voltage its components are rated for. A BMS controls access to the battery via n-Channel MOSFETs, which are rated for a particular voltage that is some amount higher than the voltage they are used for. For example, the MOSFETs in a 36V BMS are generally rated for 45+ volts.The problem arises when one of the batteries in the series fails, causing the MOSFETs in the dead battery to be exposed to a voltage that exceeds their rating. This can lead to damage to the BMS in the dead battery and, in rare cases, even a fire. To avoid these issues, it's important to take great care to ensure that neither battery dies.Using a BMS is necessary as it provides a safety measure for lithium batteries, so bypassing one or both BMS to get around this problem is not a viable solution. However, if you take the necessary precautions and ensure that neither battery dies, it is possible to wire up two batteries to make a 72V setup.It is possible to tie discharge gate control pins on each BMS together with a wire, but this is an advanced procedure that requires modifying both BMS. Another thing to consider is the voltage differential between two gate pins associated with 2 BMSs in series. There will more than likely be a dangerous difference between the two, so in addition to all the other work, isolation circuitry would have to be employed.&nbsp; Consider The Rest Of The SystemWatts equals volts times amps. If you have an ebike controller that is limited to 30 amps and you have a 48V battery, then how many watts is that? 36 Volts x 30 Amps = 1080 WattsSo, what happens if you double your system voltage by putting two 36V batteries in series?&nbsp;72 Volts x 30 Amps =&nbsp; 2160 Watts So, if the controller supports it, then you will get twice the power out of the controller. But only if you want twice the power. The thing about running a higher voltage on an ebike is that you can choose how much of that power to use. So, if you combine two batteries and adjust your power level to half of what it was before, you will have the same 1080 Watt limit at a higher running voltage.&nbsp; But remember, Watts is Volts times Amps, which means that Amps is Watts divided by Volts. So let's do the math to find out how many amps would be required to run a 72V load at 1080 Watts.1080 Watts ÷ 72 Volts&nbsp; = 15 AmpsThis means that you can get all the power you were used to while putting your batteries under half the stress as was required before. This will result in a <a href="https://cellsaviors.com/blog/get-more-cycles-from-lithium-ion-cells">much longer overall battery lifespan</a> and will provide an excellent buffer against voltage sag.&nbsp;<h2>Installing Dual Batteries In Parallel</h2>It is possible to wire two ebike <a href="https://cellsaviors.com/blog/parallel-lithium-batteries">batteries in parallel</a> to increase capacity and it is much safer and much more tolerant to error than wiring them in series, as it eliminates the risk of overvoltage damage to the BMS.When wiring two ebike batteries in parallel, it is important to ensure that the batteries are of the same type, and capacity and that they are rated for the same voltage. This is because if one battery is larger than the other, it will more than likely have lower <a href="https://cellsaviors.com/blog/measure-internal-resistance">internal resistance</a> and will provide more than its fair share of the load current.This will lead to an imbalance in the system that will be quickly and unpredictably corrected by a rush of current from the larger battery to the smaller one on every discharge. This can damage both batteries and if the wiring between the two can't support the higher currents, it could start a fire.When doing this, you have to make sure that the positive and negative terminals of each battery must be connected to the same terminals on the other battery. Before connecting the two packs together both packs need to be at the same voltage, within .1v of each ideally. If this is not done correctly, it will cause a short circuit, which can cause burns and/or ruin one or both batteries. &nbsp; Consider The Rest Of The SystemWhen adding two batteries in parallel, whether they are properly matched or not, the rest of the system doesn't know any different. It will see the same running voltage and power will be applied as normal. It is worth mentioning, however, that because there is another battery there to share the load, each battery will bear less of the load than it otherwise would have had it been the only battery in operation.This helps to extend the life of the batteries and works against the face that if the batteries are mismatched, overall life is reduced. This situation ends up creating somewhat of a balance that produces an overall net-positive effect when adding batteries in parallel, even if they are mismatched. This is why many people swear by this method and say that it works perfectly.&nbsp;<h2>Simple Way To Install Dual Batteries On An Ebike</h2>The best way to use multiple batteries on an ebike is to put them in parallel. This is only truly viable if you have two matched batteries, though. If the batteries are not matched, the best thing you can do is use a switch to toggle between them. The problem is that switches that can handle that amount of current are often expensive and bulky. So, the simple solution is a manual one.&nbsp;When your first battery dies, simply unplug it and plug the other battery in. All you have to do to make this possible is to run the wiring in the right places on your bike and put the connections in the most ideal spots for you to switch them.&nbsp;Swapping over a cable into another port is a quick, painless procedure and it is the easiest, most effective, and safest way to install dual batteries on your ebike. The only downside is the fact that it is not automatic and requires the bike to stop for a moment. This is a more than worthy tradeoff, considering its low cost and simplicity.&nbsp;There are also battery discharge combiner modules, but it is important to keep in mind that they often have relatively low current limits. For example, the first listing for the linked battery combiner specifically says to not use it with a non-geared motor. This is because without gears, starting from 0 uses quite a bit of power. Whereas the second one does not have that noted since it can handle higher amperage.&nbsp;<blockquote>[[ aff type=aff ~ link=https://amzn.to/3FsO8kx ~ title=`Dual Battery Pack Balancer` ~ image=https://admin.cellsaviors.com/storage/dual-battery-balancer.jpg ~ description=`Perfect for applications using 40A or less this will easily allow you to parallel two batteries. ` ~ height=small ~ buttonText=`Check Price`&nbsp; ]]</blockquote> <blockquote>[[ aff type=aff ~ link=https://amzn.to/3TmYqZa ~ title=`100A Dual Battery Balancer` ~ image=https://admin.cellsaviors.com/storage/100A-dual-battery-balancer.jpg ~ description=`This will work up to 100A and in the 24-72v range, much better for higher output applications!` ~ height=small ~ buttonText=`Check Price`&nbsp; ]]</blockquote> Consider The Rest Of The SystemThis is the least invasive way to add dual batteries to an ebike in terms of system characteristics. This is because the batteries are not connected at the same time, so all the precocious and disclaimers above go out the window. In fact, because the batteries are totally isolated and never used together, you can even confidently mismatch different voltages, capacities, and even cell chemistries. You could have an LFP pack for short runs as they have an extended cycle life and you could have an NMC pack for long range as they have the highest energy density. You could have a large, 48V pack for long runs and you could have a small, 72V back for short races on a track or other closed circuit. The possibilities are endless because the batteries are never connected at the same time. As long as your controller supports the voltage of whatever battery you plan on connecting to it, it will be fine.&nbsp;<h3>Conclusion</h3>Installing dual batteries on your ebike can be a great way to increase its range and speed. However, the method of connecting the batteries is crucial to ensure safe and reliable operation. Connecting the batteries in series involves connecting the positive of the first battery to the negative of the second battery, and then connecting the remaining connections to the speed controller. However, problems can arise if the batteries are not matched and one battery dies, which can overvolt the BMS in the dead battery.On the other hand, connecting the batteries in parallel involves connecting the positive of the first battery to the positive of the second battery, and then connecting the speed controller to either battery. It's important for the batteries to be at the same voltage before connecting them, and to avoid putting two batteries of different capacities in parallel as it can cause an imbalanced state of discharge and reduce the life of the system.We hope this article contained everything you wanted to know about how to install dual batteries on your ebike, thanks for reading!

How to Install Dual Batteries on an Ebike

Recovering low or 0v cells and batteries can be simple in some cases, read our guide for how to do it. 

Reviving 0v and Low Voltage Batteries and Cells

So, can you recover 0v and low voltage cells and batteries? In some cases and with some cell chemistries, it is possible to recover a 0v cell.&nbsp;Lead acid cells and battery packs can be recovered from 0V and used with almost the same performance as before. However, lithium-ion cells are too sensitive to over-discharge to be recovered from 0V and used in most applications, and cannot be serviced. To recover a lead acid battery, charge it for 10-12 hours and then measure the terminal voltage. If the battery is undervolted, then try to fill each compartment with water or use a desulfation device. To recover a lithium-ion battery pack from 0V, your only recourse is to check if the BMS has tripped or failed. If the BMS has tripped, place the battery on a charger or short the B- and P- connection on the BMS. If the BMS has failed, you will more than likely need to replace it.&nbsp;In this article, we will explain how to recover lithium ion and lead acid batteries from a 0V state. We will also go over some of the limitations of recovering cells from 0V.<h2>How To Recover a 0V Lithium Ion Cell</h2>Recovering a Lithium-Ion battery cell from zero volts is not recommended, as it can result in a fire. This is because once the cell goes under about 2.5 or 2.6 volts, a chemical reaction occurs inside the cell that permanently damages it and drastically increases its internal resistance.This means that even if you revive the cell, it will not have the same performance characteristics as it did before and will be imbalanced in terms of performance compared to the rest of the cells in the battery pack.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/jpeg&quot;,&quot;filename&quot;:&quot;low-voltage-cell-recovery.jpg&quot;,&quot;filesize&quot;:95514,&quot;height&quot;:406,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/izynWjXL2Ci8jnZZi1AHxC0Xsrc66it55jeAJPJ0.jpg&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/izynWjXL2Ci8jnZZi1AHxC0Xsrc66it55jeAJPJ0.jpg&quot;,&quot;width&quot;:294}" data-trix-content-type="image/jpeg" data-trix-attributes="{&quot;presentation&quot;:&quot;gallery&quot;}" class="attachment attachment--preview attachment--jpg"><a href="https://admin.cellsaviors.com/storage/izynWjXL2Ci8jnZZi1AHxC0Xsrc66it55jeAJPJ0.jpg"><img src="https://admin.cellsaviors.com/storage/izynWjXL2Ci8jnZZi1AHxC0Xsrc66it55jeAJPJ0.jpg" width="294" height="406"><figcaption class="attachment__caption">low-voltage-cell-recovery.jpg 93.28 KB</figcaption></a></figure>So, there are few reasons to revive a Lithium-Ion battery cell from zero volts, as just about every application requires a balanced battery pack for the best performance, reliability, and safety.&nbsp; Any time a cell falls below a particular threshold related to its chemistry, permanent damage occurs. If that cell is revived and put in any battery pack, the battery will be impossible to balance.For this reason, it is far better to replace a damaged Lithium-Ion battery cell with either a new one or a healthy one that more closely matches the characteristics of the other battery cells in the pack. If you decide to go this route check out our article on <a href="https://cellsaviors.com/blog/fix-broken-battery-pack">how to repair a broken battery pack</a> to learn more about the process.&nbsp;With that being said, if you are dead set on recovering a 0v cell, you can get a lithium-ion charger that features a cell recovery function. This mode will slowly wake up the cell and is basically the only safe way to do it. There are other ways to try to recover a 0v lithium ion cell by forcing current into it in a controlled way, but that method is far too risky and is just asking for problems. Besides, it does not produce a truly usable cell anyway.&nbsp;<h2>How To Recover a Low-Voltage Lithium Ion Cell</h2>If a lithium-ion cell has only been undervolted for a short period of time, then it will more than likely be possible to nearly fully recover it. <a href="https://www.mpoweruk.com/lithium_failures.htm">Once a cell goes below around 2.0 volts the electrodes become plated with lithium and begin to break down.&nbsp;</a>If a cell is only in this condition for a short period of time, or if it's not too far below the cutoff point, it can be recovered. In this situation, the cell needs to be charged, but not in the normal way. Instead of charging it to 4.2 volts, you instead need to charge it to somewhere around 2.7 volts and at a very low current.&nbsp;<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/png&quot;,&quot;filename&quot;:&quot;sayno-datasheet-low-voltage-cell-recovery.png&quot;,&quot;filesize&quot;:101226,&quot;height&quot;:475,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/isbZtPzxxGDukYn7aGJhUKkvpWCkZItUGOgz6Nyn.png&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/isbZtPzxxGDukYn7aGJhUKkvpWCkZItUGOgz6Nyn.png&quot;,&quot;width&quot;:521}" data-trix-content-type="image/png" data-trix-attributes="{&quot;caption&quot;:&quot;Found this in Sanyos Cell Datasheet on low voltage cell recovery writing this blog&quot;,&quot;presentation&quot;:&quot;gallery&quot;}" class="attachment attachment--preview attachment--png"><a href="https://admin.cellsaviors.com/storage/isbZtPzxxGDukYn7aGJhUKkvpWCkZItUGOgz6Nyn.png"><img src="https://admin.cellsaviors.com/storage/isbZtPzxxGDukYn7aGJhUKkvpWCkZItUGOgz6Nyn.png" width="521" height="475"><figcaption class="attachment__caption attachment__caption--edited">Found this in Sanyos Cell Datasheet on low voltage cell recovery writing this blog</figcaption></a></figure>This gives the cell an opportunity to be returned to normal. If you place it on a normal charger, it could trip the charger due to the higher-than-expected voltage difference. If it does not trip the charger and the charger tries to charge the low-voltage cell at a normal charging rate, it will likely be too much current for the cell to handle given its state. For this reason, a custom charge voltage and current will need to be used. This can easily be done by buying a specific type of charger or <a href="https://cellsaviors.com/blog/lithium-charger-diy">building your own DIY battery charger</a>.&nbsp;Any time you are trying to recover a low-voltage lithium-ion cell, the process has to be monitored continuously as it is dangerous to leave a damaged cell on a charger unattended.&nbsp; <blockquote>[[ aff type=aff ~ link=https://amzn.to/3ViQKHV ~ title=`Zanflare C4` ~ image=https://admin.cellsaviors.com/storage/3-zanflare.jpg ~ description=`This tester can help recover low voltage cells, also can be used to capacity test cells!` ~ height=small ~ buttonText=`Check Price`&nbsp; ]]</blockquote><h2>How To Recover a 0V Lithium Ion Battery Pack</h2>The lithium-ion batteries that are commonly used in many electronic devices, such as laptops and light electric vehicles have a battery management system (BMS) that monitors the voltage of each cell and ensures that they are within safe operating limits. In some cases, a lithium-ion battery may show 0V on the output even though the cells are not really at 0V. This can happen when the BMS is either tripped or has failed.In these situations, reviving a lithium-ion battery from 0V is possible because the cells are not really at 0V. The BMS is responsible for preventing overcharging and over-discharging of the cells, but if it for whatever reason fails, it can cause the battery to shut down.&nbsp;This kind of situation commonly occurs when your battery voltage is low, but not low enough to trip the BMS into over-discharge protection. But then, a sudden load is put on the battery that causes the cell voltages to momentarily dip below the low voltage cutoff, tripping the BMS. If this happens, the battery may need to be put on a charger for the BMS to wake up and show a voltage on the output.&nbsp;Encountering low or 0v battery packs where the BMS has just gone into sleep mode or the BMS has failed is common when you are <a href="https://cellsaviors.com/blog/how-to-salvage-18650-cells">salvaging lithium-ion cells and batteries</a>.&nbsp;In other cases, the BMS may have not tripped and the BMS could have a problem. If that ends up being the case, then the BMS may need to be replaced entirely.If the BMS has just tripped, the battery may need to be put on a charger for around 0.1 seconds for the BMS to return to normal. In many cases, the B- and P- connection on the BMS can be shorted out to sort of ‘jump start’ a tripped BMS. If this method does not work, nothing bad will&nbsp; happen, it just won’t work. If the BMS has failed, it will more than likely need to be replaced unless you can easily identify and replace a component that is more than likely surface mounted.&nbsp;So, a lithium-ion battery pack that has a BMS may show 0V on the output even though the cells are not really at 0V. In these cases, a lithium-ion battery pack can be fully recovered from 0V by repairing or replacing the BMS or simply placing the battery on a charger for a moment.<h2>How To Recover A 0V Lead Acid Battery</h2>One of the most common reasons a lead acid battery shows 0V is sulfation. This happens because, inside a lead acid battery, there are lead plates that are coated with lead dioxide and are separated by a porous separator.When the battery is in use, the lead dioxide reacts with sulfuric acid and produces lead sulfate and hydrogen ions. Over a period of time, the lead sulfate builds up on the lead plates and ends up forming crystals. These crystal structures reduce the surface area of the plates and limit the battery's ability to store and release energy.&nbsp;A battery can end up in this sulfated condition when it is undercharged, over-discharged, or left in a state of disuse for an extended period of time. The sulfated lead acid battery is often unable to hold a charge and may need to be replaced, but there are some ways to reverse it if it's not too bad already.&nbsp;<h3>Identifying Bad Cells</h3>To identify the bad cells in a lead acid battery, follow these steps:<ul><li>Charge the battery for at least 12 hours and then allow it to rest for 10 minutes.</li><li>Open the battery caps and fill each compartment with water to within optimum levels.</li><li>Measure the terminal voltage of the battery. A fully-charged battery should be in the range of 11.8 to 13.0 volts.</li><li>Measure the voltage of each cell and identify any cells with a voltage lower than 2 volts. These are considered bad cells.</li></ul><h3>Desulfation</h3>Once the bad cells have been identified, there are several methods for reviving a sulfated lead acid battery:<ul><li>Attaching a battery trickle charger or a smart charger to the battery and allowing it to charge continuously for a week to 10 days can sometimes do the trick.</li><li>Wiring in an <a href="https://www.amazon.com/Orange-Battery-Desulfator-Desulphator-Batteries/dp/B01DXS7IG4">electronic desulfation device</a> that constantly desulfates the battery acid solution is also a viable solution.</li><li>It is possible to add a chemical desulfator to the filling ports on the battery but those chemicals seem quite hard to come by.</li><li>In some cases, you can even top off your lead acid battery with water and then put it on a charger to bring it back from the brink.&nbsp;</li></ul><h3>Conclusion</h3>When it comes to recovering cells and battery packs from a 0V state, there are some important things to know and some caveats to consider. Both lead-acid cells and complete battery packs can be viably recovered from 0V and used in a safe way with almost the same performance as before. Lithium-ion cells, however, are more sensitive to over-discharge and are impossible to service. This means that while a lithium-ion battery pack with a BMS issue can be revived from 0V, it's not practical or safe to do the same thing with lithium-ion cells.&nbsp;To recover a lead acid battery, charge it for around 10 to 12 hours. Then, measure the terminal of the battery. After that, check the voltage of each cell and identify any cells with a voltage lower than 2 volts. If there are undervoltage cells, open the battery caps and fill each compartment with water to optimum levels or electrically add a desulfation device. When it comes to recovering a lithium-ion battery pack from 0V, the first thing to check is if the BMS BMS has tripped or failed. If the BMS has tripped, place the battery on a charger for a moment or short the B- and P- connection on the BMS. If the BMS has failed, replace the BMS or a component that is causing the failure.We hope this article provided everything that you were looking for in regards to recovering 0V and low voltage cells and batteries. Thanks for reading!

How To Recover 0v and Low Voltage Cells and Batteries

Maintaining your battery at proper temperature is crucial for longevity and health of the pack, check out this post to learn how to.  

How to Keep Batteries Warm in the Cold

Lithium-ion batteries, including LiFePO4 batteries, have a limited temperature range in which they can operate safely and efficiently. Cold temperatures can cause a reduction in the battery's performance and capacity, as well as increase the risk of damage or failure. In general, the optimal operating temperature range for lithium-ion batteries is between about 0 and 45 degrees Celsius.When a lithium-ion battery is charged in cold temperatures, the electrolyte inside the battery becomes more viscous and the chemical reactions inside the battery slow down, which can lead to overcharging and potentially dangerous thermal runaway. Charging a LiFePO4 battery in temperatures below 0°C can cause damage to the battery, reducing its capacity and lifetime.<h2>How Is Temperature Related To Performance?</h2>Lithium-ion battery performance depends on temperature. Different cell types have different temperature ranges for charging and discharging. Charging ranges are narrower and require more stringent temperature control than discharging ranges.&nbsp;The temperature also affects the charging current: lower temperatures result in lower charging currents and longer charging times. The temperature also affects the available battery capacity, causing a decrease in capacity as the temperature drops. This reduction can reach over 35% within the temperature range allowed by the manufacturer, and some technologies may experience a reduction of over <a href="https://iopscience.iop.org/article/10.1088/1757-899X/211/1/012005/pdf#:~:text=This%20is%20due%20to%20the,charging%20in%20case%20of%20NCA.">50% in this range</a>.Battery operation in temperatures that are too low or too high will result in faster degradation and reduced performance. It is recommended that batteries be operated in conditions as close to 20-25°C as possible. To help mitigate these issues, passive or active thermal conditioning systems can be integrated with the batteries to regulate their temperature.These systems can provide heating, cooling, or both, and can utilize a variety of methods, such as heated or cooled air, ventilation with ambient air, or liquid heating and cooling. In addition to protecting the batteries from overheating or overcooling, these systems aim to maintain a consistent temperature throughout the battery pack. This is important because cells operating at different temperatures have different operating specifications, and this difference can lead to faster wear and reduced functionality of the battery pack.<h2>How Do You Protect Batteries From The Cold?</h2>There are several different ways to protect batteries from the cold, ranging from simple, passive solutions to complex, active solutions that require heating elements and microcontrollers:Insulation: Wrapping the battery in insulation material, such as foam or a special battery blanket, helps to reduce heat loss and maintain a stable temperature. This type of insulation creates a barrier around the battery, trapping heat and preventing it from escaping into the environment.Battery Blankets: Battery blankets are specially designed covers made of insulating material that fit snugly around the battery. They help to maintain a consistent temperature for the battery, keeping it warm and reducing the risk of failure. Battery blankets come in various sizes and shapes to fit different types of batteries and are designed to be durable, flexible, and easy to install.Heated Enclosure: Placing the battery in a heated enclosure that is kept warm through heating elements or other means can help to protect it from the cold. The enclosure acts as a barrier against the cold, trapping heat and maintaining a stable temperature for the battery. Heated enclosures can be powered by electricity or other energy sources and are available in various sizes and shapes to fit different types of batteries.Charge Maintenance: Keeping the battery adequately charged before exposure to cold temperatures can reduce the risk of over-discharging, which can cause damage and shorten the lifespan of the battery. By maintaining an appropriate level of charge, the battery is better able to withstand cold temperatures and continue to deliver reliable performance.Avoid Overloading: Overloading the battery in cold conditions can reduce its performance and increase the risk of failure. Avoiding overloading by not exceeding the battery's maximum capacity or voltage rating can help to protect it from the cold and ensure that it continues to deliver reliable performance.<h2>What's The Easiest Way To Keep Batteries Warm?</h2>Insulation is an effective and simple way to maintain a stable temperature for batteries, especially in low-temperature environments. Insulation helps to reduce the loss of heat from the battery and keeps it warm. This can be done in several ways, such as wrapping the battery in insulation material, like foam or a specially designed battery blanket, or placing the battery inside an insulated enclosure.A battery blanket is a specially designed insulating cover that fits securely over the battery. It helps to maintain a consistent temperature and protect the battery from extreme temperature changes.The battery blanket is made of insulating material that acts as a barrier between the battery and the surrounding environment, preventing the transfer of heat. This helps to keep the battery at an optimal temperature, which prolongs its life and improves its performance. By using a battery blanket, you can ensure that your battery stays warm and protected, even in harsh weather conditions.<blockquote>[[ aff type=aff ~ link=https://batteryhookup.com/discount/CS5?redirect=/collections/accessories/products/24-48v-150w-battery-heating-pad-hi-heat-made-in-usa ~ title=`24/48v 150w Battery Heating Pad` ~ image=https://admin.cellsaviors.com/storage/24-48v-battery-heating-pad.jpeg ~ description=`These are usually very expensive but here you can get them for $6. They were all removed from working battery packs that did not need them and are in working condition.` ~ height=small ~ buttonText=`Check it out!`&nbsp; ]]</blockquote><h2>How To Build A Battery Temperature Stabilization System</h2>It's easier than you may think to add a heating element that is integrated into the battery or its enclosure. This allows for more precise temperature control, as the heating element is in direct contact with the battery. The heating element can be controlled by a microcontroller such as an Arduino. The Arduino can be programmed to monitor the temperature of the battery using temperature sensors, and adjust the heating element accordingly to maintain a steady operating temperature.An overview of controlling a heating element with an Arduino while monitoring temperature sensors would include the following steps:<ul><li>Connect a <a href="https://www.amazon.com/HiLetgo-Temperature-Humidity-Electronic-Practice/dp/B01N9BA0O4/ref=sr_1_1_sspa?keywords=arduino%2Btemperature%2Bsensor&amp;qid=1675273876&amp;sprefix=arduino%2Btemper%2Caps%2C200&amp;sr=8-1-spons&amp;spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzT01IS1A4TVo4MlJIJmVuY3J5cHRlZElkPUEwNzAzMzcxM1NOTFdDMTg5Nks5VyZlbmNyeXB0ZWRBZElkPUEwMDM3MTg1MVYzQzdSQ0QzUUZVTyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU&amp;th=1">temperature sensor</a> (such as a thermistor) to the <a href="https://www.amazon.com/HiLetgo-Development-ESP8285-Wireless-Internet/dp/B07BK435ZW">Arduino</a>.</li><li>Connect the <a href="https://www.amazon.com/Insulated-Constant-Temperature-Thermostatic-PTCYIDU/dp/B0BNZSHKJX">heating element</a> to the Arduino, typically via a <a href="https://www.amazon.com/EPLZON-Trigger-Driving-Adjustment-Electronic/dp/B09LLR675M">MOSFET</a> or relay.</li><li>Write a program for the Arduino to read the temperature sensor and compare it to a set point temperature.</li><li>If the temperature is below the set point, the program turns on the heating element to raise the temperature.</li><li>If the temperature is above the set point, the program turns off the heating element to maintain the temperature.</li><li>Repeat steps 3 through 5 continuously in a loop to monitor and maintain the temperature.</li></ul>You can do the same thing without a heating element but it would only provide a limited amount of protection from the cold. This passive solution relies on heat internally generated by the battery while it is under load. You can use an Arduino, temperature sensor, and a small motor to regulate the temperature of a battery by opening and closing a flap vent:<ul><li>Connect the <a href="https://www.amazon.com/HiLetgo-Temperature-Humidity-Electronic-Practice/dp/B01N9BA0O4/ref=sr_1_1_sspa?keywords=arduino%2Btemperature%2Bsensor&amp;qid=1675273876&amp;sprefix=arduino%2Btemper%2Caps%2C200&amp;sr=8-1-spons&amp;spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzT01IS1A4TVo4MlJIJmVuY3J5cHRlZElkPUEwNzAzMzcxM1NOTFdDMTg5Nks5VyZlbmNyeXB0ZWRBZElkPUEwMDM3MTg1MVYzQzdSQ0QzUUZVTyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU&amp;th=1'">temperature sensor</a> to the <a href="https://www.amazon.com/HiLetgo-Development-ESP8285-Wireless-Internet/dp/B07BK435ZW">Arduino </a>and calibrate it to read the temperature of the battery.</li><li>Set a target temperature for the battery in your Arduino code.</li><li>In the code, use a control loop to continuously monitor the temperature of the battery.</li><li>If the temperature exceeds the target temperature, activate the small <a href="https://www.amazon.com/6-Pack-MG996R-Torque-Digital-Helicopter/dp/B0BMM1G74B">motor</a> to open the flap vent and allow heat to escape.</li><li>If the temperature drops below the target temperature, deactivate the motor to close the flap vent and trap heat inside the battery.</li><li>Repeat the monitoring and control loop continuously to maintain a set operating temperature.&nbsp;</li></ul>For a setup like this to work, it would require the battery compartment to be designed in such a way that it provided absolutely no ventilation to the battery, giving the system an opportunity to build up heat. The ventilation system would have to be designed to be effective at regulating the heat simply by opening a channel for air to pass through.A system like this would allow you to regulate the temperature of the battery by controlling the ventilation, and ensure that the battery operates within a safe temperature range. A few simple modifications could be made to a system like this, such as adding a fan, that would make the design much easier as the fan could be relied on to effectively carry away excess current.&nbsp;<h3>Conclusion</h3>Lithium-ion batteries have a certain operating temperature range for optimal performance. Charging a battery when it's too cold can damage the battery because of complex interactions the cell chemistry has below a certain temperature threshold.To keep batteries warm, there are several methods including insulation, battery blankets, heated enclosures, charge maintenance, and avoiding overloading. The most effective way to keep batteries warm would be to build a battery temperature stabilization system by integrating a heating element into the battery or its enclosure and controlling it with a microcontroller like an Arduino. The Arduino program reads the temperature sensor, compares it to a set point temperature, and turns on or off the heating element as needed to maintain the temperature. A passive solution of temperature regulation involves relying on heat generated internally by the battery and using an Arduino, temperature sensor, and motor to regulate the temperature by opening and closing a flap vent. The most simple way to keep batteries warm is through insulation by wrapping the battery in foam or a battery blanket or placing it in an insulated enclosure. This method won’t ever be as effective as the more active methods listed above, but for many applications, a passive solution will work just fine.We hope this article answered every question you had in regards to how to keep batteries warm. Thanks for reading!

How To Keep Batteries Warm

Find out how cell level fusing lithium cells works and how you can implement it on your next battery build!

Cell Level Fusing: How it works and How to Easily Implement it

Cell level fusing is a safety measure for lithium-ion batteries that provides a physical barrier to prevent overcharging and overheating.&nbsp;Cell-level fusing works by installing a fuse at the cell level, which will automatically cut off power to the battery if it exceeds a certain temperature or voltage. This helps to prevent dangerous situations such as explosions or fires caused by overheating or overcharging. The main benefit of doing cell-level fusing is that it improves the reliability and safety of lithium-ion batteries. Cell level fusing prevents a dramatic over-current situation which can lead to overheating and thermal runaway. Cell level fusing somewhat helps to prolong a battery's overall lifespan by essentially removing bad cells. I say ‘somewhat’ because once a cell is removed there will be an imbalance in the P group which will inevitably lead to an imbalance in the S groups, which reduces the overall battery lifespan. It’s important to consider, however, that this reduced lifespan is still much longer than if the bad cell had not been removed from the circuit.&nbsp;For the longest time, wire bonding was the most viable option for cost-effective implementation of cell-level fusing. It’s a process that uses ultra-thin wires that function as a fuse to connect the battery cells to a bus bar. This method is relatively inexpensive but it can be rather difficult to implement. Luckily, there is a much more intuitive and economical solution, which is Batty Hookup cell-level fuse sheets. These nickel sheets are specially manufactured so that every cell point is fused. This is achieved by cutting a specific shape into the nickel where the cell is usually welded. Using these sheets makes it so that you can build a lithium-ion battery in a totally traditional way and it will just automatically be fused.In this article, we will cover the basics of cell-level fusing, why it's so beneficial, and what some of its current limitations are. &nbsp;<h2>What Is Cell Level Fusing?</h2>Cell level fusing is a technology that uses a fuse to connect each individual cell of a lithium-ion battery together to prevent overcharging, over-discharging, and overheating. This ensures that if one cell becomes damaged, it will be much less likely to cause a chain reaction that could lead to a fire or explosion.Potential Applications For Cell-Level FusingCell-level fusing technology has the potential to improve the safety and performance of lithium-ion batteries in a wide range of industries, including electric vehicles and energy storage systems. In electric vehicles, cell-level fusing is pretty much critical. You have to consider that there are literally thousands of cells in a car battery pack.&nbsp;<h2>How Does Cell Level Fusing Compare To Other Battery Safety Mechanisms?</h2>Cell level fusing is just one of many safety measures that can be used in lithium-ion batteries. Other measures include thermal management, which helps to keep the battery at a safe temperature, and overcharge protection, which prevents the battery from being charged too much. Cell level fusing is unique in that it provides a physical barrier to prevent an out-of-control cell from hurting the rest of the pack.&nbsp;Another thing to consider is this: Let's say you have a non-fused battery pack and a cell goes haywire. There is a chance that the heat alone can move from one cell to another simply through convection. And remember things that carry electricity well generally carry heat well. A non-fused pack has an intentionally large, wide conductor connecting all the cells. In contrast, a fused pack has only a just enough conductor connecting the cells to the rest of the system. This means if things do go badly for a given cell, the excess heat will not have the main, thermally conductive path to spread to other cells that a non-fused pack will.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/jpeg&quot;,&quot;filename&quot;:&quot;fused cells on bus bar.jpg&quot;,&quot;filesize&quot;:105820,&quot;height&quot;:360,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/5w3D8qBxRUzyHAslwOit5ZIJYzoAJfFslhJYTd17.jpg&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/5w3D8qBxRUzyHAslwOit5ZIJYzoAJfFslhJYTd17.jpg&quot;,&quot;width&quot;:640}" data-trix-content-type="image/jpeg" data-trix-attributes="{&quot;presentation&quot;:&quot;gallery&quot;}" class="attachment attachment--preview attachment--jpg"><a href="https://admin.cellsaviors.com/storage/5w3D8qBxRUzyHAslwOit5ZIJYzoAJfFslhJYTd17.jpg"><img src="https://admin.cellsaviors.com/storage/5w3D8qBxRUzyHAslwOit5ZIJYzoAJfFslhJYTd17.jpg" width="640" height="360"><figcaption class="attachment__caption">fused cells on bus bar.jpg 103.34 KB</figcaption></a></figure><h2>What Happens If A Cell Goes Bad In A Battery That Features Cell Level Fusing?</h2>If a cell goes bad in a battery that features cell-level fusing, the fuse associated with that cell will activate and open the circuit, preventing the damaged cell from further charging or discharging and preventing any potential chain reaction that could lead to a fire or explosion. This is basically the entire point of cell-level fusing.Once the fuse is activated, the damaged cell is equal to having been physically removed from the pack. No joke. It's exactly the same as turning the battery off, breaking it down, taking out the bad cell, and putting the battery back together. All automatically. This, of course, will reduce the capacity of the battery pack, but not just in the obvious way. As previously mentioned, the new state of the battery with the bad cells removed will be an imbalanced battery.&nbsp;To be totally honest, the best thing you can do if a cell goes bad and a fuse activates is to intentionally destroy the same number of fuses that burned out, but in every other cell group.&nbsp;For instance, If you have a 5S15P battery and one of the cells in a P group goes bad and blows its fuse, it’s best to disable one of the cells in every other P group. This will turn the battery into what is effectively a 5S14P battery, but at least the <a href="https://cellsaviors.com/blog/balance-lithium-battery">battery pack will be in balance</a>.&nbsp;<h3>Challenges Of Cell Level Fusing</h3>While cell-level fusing can be an effective safety measure for lithium-ion batteries, implementing it on a large scale can be challenging. One major challenge is that cell-level fusing requires a fuse to be placed in each individual cell of the battery, which can add complexity and cost to the manufacturing process. Additionally, the fuses themselves can add a small amount of resistance to the battery, which can slightly reduce its overall performance.<h2>What Is The Easiest Way To Implement Cell Level Fusing?</h2>Historically, wire bonding was just about the only reasonable way that one could achieve cell-level fusing. This is a technique that involves using thin wires made of materials such as gold or aluminum to connect the individual cells within a battery.&nbsp;To implement cell-level fusing with wire bonding, a fuse is connected in series with each cell using a specialized conductor and specialized machines. These fuse wires are designed to activate at a specific current or temperature threshold, providing an additional layer of safety to your project.&nbsp;Overall, wire bonding is a viable option for implementing cell-level fusing in lithium-ion batteries, but it has a massive learning curve and again, requires specific, specialized equipment. It is, however, highly scalable. If you are feeling discouraged, fret no. There is a better way.&nbsp;<h2>An Even Easier Way To Implement Cell-Level Fusing</h2>If wire bonding sounds a bit overwhelming, fret not. Battery hookup makes a special nickel conductor that is specifically made for cell-level fusing. These specially cut nickel conductors make it extremely easy to add cell-level fusing to any lithium-ion battery project.&nbsp;<blockquote>[[ aff type=aff ~ link=https://www.batteryhookup.com/discount/CS5?redirect=/collections/accessories/products/nickel-fuse-2p-wide-continuous-roll-by-the-foot-18650-cell-level-fusing ~ title=`Fused Nickel Strip` ~ image=https://admin.cellsaviors.com/storage/fused nickel strip.jpg ~ description=`Fuses blow at 8 amps and can carry 3 amps continuously. ` ~ height=small ~ buttonText=`5% Off Using This Link`&nbsp; ]]</blockquote> These sheets from Battery Hookup take all the fuss out of cell-level fusing. They make it so that the lithium-ion construction process is no different than building a non-fused battery. They are low-cost, easy to use, and reliable. There are, however, some drawbacks. They are only available in linear formats, so if you are dreaming up an easy-to-build, individually fused, highly compact, offset battery pack, you are out of luck for now.&nbsp; Also, because the fuse links are built into the sheets, there is no way to change them. That means if the fuse threshold is too high or too low for your application, then these sheets won't work for you. For more information on what these sheets can handle, I suggest you visit the battery hookup website for the most updated information.&nbsp;<h3>Cell Level Fusing Will Get Cheaper And Easier Over Time&nbsp;</h3>As cell-level fusing technology continues to evolve, researchers are exploring new materials and designs that can improve the performance and <a href="https://cellsaviors.com/blog/lithium-cell-battery-safety">safety of lithium-ion batteries</a>. For example, some are experimenting with using new types of fuses made from materials that are more heat-resistant or that can withstand higher currents. Others are exploring new designs for the fuses themselves, such as using multiple fuses in parallel to provide additional protection.The cost of cell-level fusing will likely come down as technology advances and more companies enter the market. Some key areas that will need to be developed include:<ul><li>Improved materials for fusing cells, such as more efficient and durable fuses</li><li>Better methods for aligning and fusing cells, such as advanced imaging techniques</li><li>Development of high-throughput techniques for fusing large numbers of cells at once</li><li>Advancements in automation to reduce labor costs</li></ul><h3>Conclusion</h3>Whether you are new to lithium-ion batteries or have been building them for years, the concept of cell-level fusing is generally relatively unexplored.&nbsp;Cell-level fusing is a technique that helps improve the safety and reliability of lithium-ion batteries by installing a fuse at the cell level. This fuse automatically cuts off power if the battery exceeds a certain temperature or voltage, preventing potential dangers such as overheating, overcharging, and the possibility of explosions or fires.In the past, wire bonding was a popular and cost-effective method for implementing cell-level fusing, but it can be challenging to implement. Today, there is a more efficient solution in the form of Batty Hookup cell-level fuse sheets. These nickel sheets are designed to fuse every cell point, making it easy to <a href="https://cellsaviors.com/blog/building-a-battery-pack-from-18650-cells">build a battery pack from 18650 cells</a> with automatic fusing. The sheets are made by cutting specific shapes into the nickel where the cell is usually welded.While cell-level fusing somewhat prolongs a battery's lifespan by removing bad cells, it also creates an imbalance in the battery's <a href="https://cellsaviors.com/blog/series-vs-parallel">series and parallel groups</a>, which can reduce the overall battery lifespan. However, this reduced lifespan is still much longer than if the bad cell had not been removed from the circuit. Also, the battery can be brought back into balance by strategically clipping other fuses to match everything back up again.&nbsp;We hope this article had everything you needed to know about cell-level fusing, thanks for reading!!

Cell Level Fusing for Lithium Batteries

Looking to measure the internal resistance of a battery or cell? We have a step by step process to help get it done!

How to Find  and Measure Internal Resistance of a Battery

Internal resistance in a lithium-ion battery is a measure of the resistance to the flow of electrical current within the battery. It is caused by factors such as the quality of the electrodes, separator, and electrolyte. Low internal resistance is important for a battery because it allows for efficient transfer of energy, resulting in higher output power and longer battery life. Measuring internal resistance can provide insight into the battery's health, performance, and aging. It is important to monitor internal resistance to detect any performance degradation and predict battery failure, making it a crucial factor in the design, optimization, and maintenance of lithium-ion batteries.Internal resistance (IR) of a lithium-ion battery can be measured using a variety of different techniques. The most widely used are EIS and DC load testing. EIS, or Electrochemical Impedance Spectroscopy, involves applying a small sinusoidal signal (typically in the MHz range) to the battery and measuring the resulting voltage and current. The ratio of the voltage to the current is known as the impedance, which can be used to calculate the internal resistance of the battery. EIS can be performed using specialized equipment, such as a potentiostat or a frequency response analyzer. This method is widely used in industry and has high accuracy and scientific applications.The second and much more commonly used method for measuring the internal resistance (IR) of a lithium-ion battery is to apply a load to the battery and measure the voltage drop across the terminals. This method is also known as load testing or DC resistance testing. It is a simple and widely used method for measuring the IR of a battery. In this method, a load is applied to the battery by connecting a resistor across its terminals. The load is typically chosen to be a low-value resistor in order to minimize the impact on the battery. A multimeter is then used to measure the voltage across the terminals of the battery. The IR of the battery can be calculated by dividing the voltage drop across the terminals by the load current.In this article, we will explain what IR (Internal Resistance) is. We will also go over how to test for it and what the normal range of IR is for <a href="https://cellsaviors.com/blog/testing-and-grading-lithium-ion-cells">healthy battery cells</a>.&nbsp;<h2>What is IR (Internal Resistance)?</h2>Internal resistance (IR) is an important characteristic of a lithium-ion battery because it can greatly affect the performance of the battery. The IR of a battery represents the resistance to the flow of current within the battery, and as such, it can have a significant impact on the battery's ability to deliver power.High internal resistance can lead to a number of issues including:<ul><li>Voltage drop: As a load is applied to the battery, the voltage across the terminals will drop, which can lead to a reduction in the available power.</li><li>Reduced efficiency: High IR can lead to a reduction in the overall efficiency of the battery, as more energy is lost as heat rather than being delivered to the load.</li><li>Reduced capacity: High IR can lead to a reduction in the capacity of the battery, as the voltage across the terminals will drop more quickly as the battery is discharged.</li><li>Reduced cycle life: High IR can lead to a reduction in the number of charge/discharge cycles a battery can go through before it needs to be replaced.</li></ul>Having a low internal resistance is desirable as it leads to better performance and longer battery life. Low internal resistance allows the battery to deliver more power and maintain a higher voltage across the terminals, which leads to better efficiency and capacity. Using IR to pick the optimal cells when <a href="https://cellsaviors.com/blog/building-a-battery-pack-from-18650-cells">building a battery pack</a> can ensure the best performance. &nbsp;Measuring the internal resistance of a lithium-ion battery is important to ensure that the battery is in good condition and to ensure that it will perform as expected. It is also important for battery management systems to monitor the internal resistance of the batteries they are managing to detect any issues and take corrective action to mitigate them.<h2>How To Measure IR Step By Step</h2>Step 1: Connect the resistor: Connect the resistor across the terminals of the battery by connecting the positive lead of the resistor to the positive terminal of the battery and the negative lead of the resistor to the negative terminal of the battery. Use the formula below to determine what resistor to use.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/jpeg&quot;,&quot;filename&quot;:&quot;load Resistor Formula.jpg&quot;,&quot;filesize&quot;:89288,&quot;height&quot;:349,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/JyS94lToiKYPlLrkhB71JIMNNgUJhzUZPu0QFR1O.jpg&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/JyS94lToiKYPlLrkhB71JIMNNgUJhzUZPu0QFR1O.jpg&quot;,&quot;width&quot;:750}" data-trix-content-type="image/jpeg" data-trix-attributes="{&quot;presentation&quot;:&quot;gallery&quot;}" class="attachment attachment--preview attachment--jpg"><a href="https://admin.cellsaviors.com/storage/JyS94lToiKYPlLrkhB71JIMNNgUJhzUZPu0QFR1O.jpg"><img src="https://admin.cellsaviors.com/storage/JyS94lToiKYPlLrkhB71JIMNNgUJhzUZPu0QFR1O.jpg" width="750" height="349"><figcaption class="attachment__caption">load Resistor Formula.jpg 87.2 KB</figcaption></a></figure>Step 2: Measure the voltage drop: Use the multimeter to measure the voltage drop across the terminals of the battery. Ensure that the multimeter is set to measure DC voltage.Step 3: Calculate IR: Divide the voltage drop across the terminals by the load current. The load current can be calculated by dividing the voltage across the resistor by the value of the resistor.Step 4: Record the results: Record the IR value you have obtained, as this can be used to compare with other batteries and to monitor the battery's performance over time.<h2>Internal Resistance (IR) Testers</h2>If you want a more simple, more straightforward way to measure IR, you could always use a dedicated IR testing device. Regardless of whether you are doing it manually or using a device that does it for you, it’s important to remember that IR readings will vary depending on how charged the battery is. For this reason, it’s always best to measure IR when the battery or cell is within its nominal voltage range. However, this varies from cell to cell so always consult the cells datasheet.&nbsp;<blockquote>[[ aff type=aff ~ link=https://amzn.to/3JAaOT5 ~ title=`YR1035+ 4 Line IR Tester ` ~ image=https://admin.cellsaviors.com/storage/yr1035 ir tester.jpg ~ description=`` ~ height=small ~ buttonText=`Check Price`&nbsp; ]]</blockquote> <blockquote>[[ aff type=aff ~ link=https://amzn.to/3HwLhY6 ~ title=`RC3563 IR Tester` ~ image=https://admin.cellsaviors.com/storage/518UzdTF4IL._SX522_.jpg ~ description=`` ~ height=small ~ buttonText=`Check Price`&nbsp; ]]</blockquote><h2>Drawbacks of Having High IR</h2><h3>High IR, The Silent Disappointer</h3>It's important to know what a high IR is and how it affects performance. As a result of being unaware, a user may never realize that they are not getting the full power of their battery. High IR in a battery causes a voltage drop under load, meaning that the voltage delivered to the load is lower than the voltage of the battery itself.&nbsp;This results in a reduced amount of power being delivered to the load and the user not getting the full potential power of the battery. If a user is unaware of this phenomenon, they may think that their battery is performing normally, when in fact it is not delivering the full power it is capable of. This can result in the battery not being able to power the device for as long as it should or the device not functioning optimally.The reduction in power delivered to the load due to high IR can also have a significant impact on the overall life of the device being powered. When the device is not receiving the full power it needs to operate, it is put under more strain and can generate more heat.&nbsp;<h3>High IR, The Keeper Of The Flame</h3>When a voltage drop occurs, it means that some energy is being lost, and this energy has to go somewhere. In electrical systems, energy is often converted into heat, which is why a voltage drop can cause something, somewhere to get hot. This can happen in the battery itself or in other components within the electrical system, such as cables or connectors.The heat generated by the voltage drop can cause damage to the components, leading to reduced reliability and a shorter lifespan. Furthermore, the heat can also pose a <a href="https://cellsaviors.com/blog/lithium-cell-battery-safety">safety risk</a>, as it can cause components to become hot enough to start a fire. This is why it is important to minimize voltage drops in electrical systems to maintain safety, reliability, and performance.<h2>What Is A Good IR For Lithium Ion Cells?</h2>The normal internal resistance (IR) range for lithium-ion cells can vary depending on the type of cell and the manufacturer's specifications. However, in general, the IR of a new and healthy lithium-ion cell should be less than 20 milliohms (mΩ) for small cells (such as those used in mobile devices) and less than 100 mΩ for larger cells (such as those used in electric vehicles). As the cell ages or is used more frequently, the IR may increase.It's important to note that different types of lithium-ion batteries will have different internal resistance ranges. For example, LiFePO4 batteries, which are known for their high thermal stability, have a lower internal resistance compared to LiCoO2 or LiMn2O4 batteries. Additionally, the internal resistance can vary depending on the temperature, state of charge, and the history of charge-discharge cycles. A new battery will have a lower internal resistance than a used one.In general, a lower internal resistance value is desirable, as it indicates that the battery will be able to deliver more power and have a longer lifespan. However, it's important to keep in mind that internal resistance is just one of many factors that affect a battery's performance and lifespan. Other factors such as capacity, temperature, and charge-discharge cycles also play a role.<h3>Conclusion</h3>The internal resistance (IR) of a lithium-ion battery plays a critical role in determining the performance and lifespan of the battery. A high IR results in a voltage drop under load, which can lead to reduced efficiency, capacity, and cycle life of the battery. This can also result in the battery not delivering its full potential power to the device, which can put the device under more strain and generate more heat. Measuring the internal resistance of a battery is important to ensure that it is in good condition and to monitor its performance over time.&nbsp;The two most commonly used methods for measuring IR are EIS (Electrochemical Impedance Spectroscopy) and DC load testing. EIS is a high-precision method used in industry and scientific applications, while DC load testing is a simple and widely used method for measuring IR. DC load testing involves applying a load to the battery and measuring its voltage drop. The voltage drop is used to calculate the battery's internal resistance. This is typically done by applying a constant current load to the battery and measuring the voltage across the battery before and after the load is applied. The internal resistance can then be calculated using Ohm's law (V=IR).&nbsp;In order to maximize the performance and lifespan of a lithium-ion battery, it is important to monitor its internal resistance and take corrective action when necessary. By understanding the importance of IR and regularly monitoring it, users can ensure that their battery is delivering its full potential power and that the device being powered is operating optimally.We hope this article answered all the questions you had about how to measure IR, thanks for reading!!

How To Measure Battery IR (Internal Resistance)

Want to build your own DIY solar system to power your house? We put together all the steps from planning to install!

How To Build A DIY Home Solar System

How To Build A DIY Solar System

Learn the differences between active and passive balancing so you can make an informed decision on which is best for your build. 

Active Balancing vs Passive Balancing Differences

Balancing lithium-ion batteries is crucial for ensuring the safe, efficient, and long-lasting operation of the battery pack. In a lithium-ion battery pack, individual cells are connected in series to increase the voltage and overall energy storage capacity. However, due to manufacturing variations and the inherent characteristics of lithium-ion cells, the cells in a pack can become imbalanced in terms of their state of charge.This can lead to a number of problems, such as reduced overall performance and capacity, increased risk of thermal runaway, and reduced overall life of the battery pack. <a href="https://cellsaviors.com/blog/balance-lithium-battery">Balancing the battery pack</a> ensures that each cell in a battery pack is at the same state of charge, which helps to mitigate these issues and ensure safe and efficient operation.Active balancing redistributes charge among the cells in a battery pack to ensure that they all have the same state of charge with a dedicated circuit, which monitors the voltage of each cell and adjusts the charging and discharging current accordingly. Active balancing is more accurate and faster than passive balancing. On the other hand, passive balancing relies on Ohm’s Law and the natural cell and balance resistor characteristics to bring cells to the same state of charge. Passive balancing is generally less accurate and slower than active balancing and may take longer to achieve the desired result.&nbsp;In this article, we will explain the difference between active and passive balancers, and we will elaborate on how lithium-ion batteries work, why lithium batteries need to be balanced, and the pros and cons of active or passive balancing.<h2>What’s The Difference Between Active And Passive Balancers?</h2>Active balancing refers to the process of actively redistributing charge among the cells in a lithium-ion battery pack to ensure that they all have the same state of charge. This is typically done using a dedicated circuit in addition to BMS (battery management system), which has the capability of transferring energy from one cell group to the other. Active balancing can be performed in real-time and is typically more accurate and faster than passive balancing.Passive balancing, on the other hand, relies on the natural discharge rate of the cells to bring them to the same state of charge. This is achieved by simply placing a small load on the cell or cell group. Passive balancing is generally less accurate and slower than active balancing and may take longer to achieve the desired result.Both methods have the advantage of maintaining the cells in a battery pack at an equal state of charge, but active balancing does that much more effectively. This extends the overall life of the battery pack. It also allows for a higher state of charge and discharge rate, which can be beneficial in applications where high power is required.Passive balancing, on the other hand, is simpler and less expensive to implement, as it does not require any additional circuitry other than the always-required BMS.&nbsp;The most important thing to remember is that active balancing is more accurate and efficient but requires a dedicated BMS, while passive balancing is simpler and less expensive but less accurate. Both methods have their pros and cons and the choice between them will depend on the specific application and requirements.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/jpeg&quot;,&quot;filename&quot;:&quot;picture showing series group voltages balanced.jpg&quot;,&quot;filesize&quot;:26303,&quot;height&quot;:246,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/Bpsnajj6tni6jv1fAX3ahhU1aqHirhLCaKvgjPPv.jpg&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/Bpsnajj6tni6jv1fAX3ahhU1aqHirhLCaKvgjPPv.jpg&quot;,&quot;width&quot;:293}" data-trix-content-type="image/jpeg" data-trix-attributes="{&quot;presentation&quot;:&quot;gallery&quot;}" class="attachment attachment--preview attachment--jpg"><a href="https://admin.cellsaviors.com/storage/Bpsnajj6tni6jv1fAX3ahhU1aqHirhLCaKvgjPPv.jpg"><img src="https://admin.cellsaviors.com/storage/Bpsnajj6tni6jv1fAX3ahhU1aqHirhLCaKvgjPPv.jpg" width="293" height="246"><figcaption class="attachment__caption">picture showing series group voltages balanced.jpg 25.69 KB</figcaption></a></figure><h2>What Is Balance Current?</h2>Balance current is the measure of how fast an active or passive balancer can balance. It is the current that is used by a battery management system (BMS) to redistribute charge among the cells in a battery pack, as part of the active balancing process. The balance current is typically a small fraction of the overall charging or discharging current of the battery pack, and is used to adjust the state of charge of cells that are out of balance with the other cells in the pack.The balance current is determined by the BMS or external balancer based on the voltage and state of charge of each individual cell. The current is used to adjust the cell voltages in real-time to ensure that all the cells in the pack are at the same state of charge. Balance current can be positive or negative depending on whether the current is flowing into or out of the cell in question.&nbsp;In summary, balance current is the current used to ensure that all the cells in a lithium-ion battery pack have the same state of charge.&nbsp;<h2>What Happens When Cells Become Unbalanced?</h2>When cell groups in a lithium-ion battery pack become imbalanced, the overall performance and capacity of the pack is reduced and the risk of thermal runaway and reduced overall life of the battery pack increases.For example, let's say you are <a href="https://cellsaviors.com/blog/building-a-battery-pack-from-18650-cells">building a battery pack</a> that has 10 cells connected in series, and the target state of charge for each cell is 4.0V. So, you charge that battery to 40 volts. Unknown to you, however, one of the cell groups has a slightly lower voltage of 3.8V. If you have a charge voltage of 40V and one of the cell groups is at 3.8V, then that leaves 36.2 volts to be split up between the remaining 9 cell groups. This means that the other cells are being charged to 4.02V instead of 4.0V. That's how a drastically lower cell group can cause the other cells to get overcharged.&nbsp;In this scenario, you can see how the undamaged cells can be given a voltage that is disproportionate to the battery pack's state of charge. As the battery is depleted, the low cell group will reach LVC (Low Voltage Cutoff) first, causing the BMS to shut down the battery even though there is still plenty of energy left in the other 9 cell groups.&nbsp;<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/jpeg&quot;,&quot;filename&quot;:&quot;showing different unblanced battery packs.jpg&quot;,&quot;filesize&quot;:44577,&quot;height&quot;:274,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/55BF1nwE7OEZMFQDnNC6QmckPmzmnMaRUsV46yOV.jpg&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/55BF1nwE7OEZMFQDnNC6QmckPmzmnMaRUsV46yOV.jpg&quot;,&quot;width&quot;:698}" data-trix-content-type="image/jpeg" data-trix-attributes="{&quot;presentation&quot;:&quot;gallery&quot;}" class="attachment attachment--preview attachment--jpg"><a href="https://admin.cellsaviors.com/storage/55BF1nwE7OEZMFQDnNC6QmckPmzmnMaRUsV46yOV.jpg"><img src="https://admin.cellsaviors.com/storage/55BF1nwE7OEZMFQDnNC6QmckPmzmnMaRUsV46yOV.jpg" width="698" height="274"><figcaption class="attachment__caption">showing different unblanced battery packs.jpg 43.53 KB</figcaption></a></figure><h2>Active Balancing vs Passive Balancing, Which Is Best?</h2><h3>Active Balancing</h3>Active balancing is best suited for high-power applications where high accuracy and fast response times are crucial. Some examples of use cases where active balancing would be best include:<ul><li>Electric Vehicles: In electric vehicles, the battery pack is subjected to a wide range of temperatures, high currents, and frequent charge and discharge cycles. So, it's best to have active balancing in electric vehicles so that energy can be distributed where it's needed as quickly as possible.</li><li>Home Energy Storage Systems: In <a href="https://cellsaviors.com/blog/diy-powerwall">powerwall systems</a>, the battery pack is used to store energy from renewable sources and to provide backup power during power outages. Active balancing is best for this application because it provides the longest possible run time for a battery, which could be critical if you are depending on a battery to power your home.</li><li>High Current Applications: Active balancing is best for high current applications because active balancing has a much quicker and much more efficient way of balancing cells compared to passive balancing. This is ideal for applications that place a large load on the cells.&nbsp;</li></ul>Active balancing helps to ensure that the cells in the pack are all at the same state of charge by actively transferring energy from high cells to low cells. This drastically extends the life of the battery pack and improves performance by a significant margin.<h3>Passive Balancing</h3>When it comes to balancing methods, it's important to consider the specific requirements of your application. Either active or passive balancing could be suitable, depending on the accuracy, speed, cost, and safety needs of your project. Sure, passive balancing is the more simple solution, but it’s still an extremely effective way of keeping all the cells in the pack at the same state of charge. This can be true even in areas that are usually dominated by active balancing.&nbsp;For example, electric vehicles often require high accuracy and fast response times, but passive balancing can still be used in many applications, here are a few:&nbsp;<ul><li>Low-power electric vehicles: For low-power electric vehicles, such as e-bike batteries, scooters, and personal mobility devices, the battery pack is not subjected to the same high currents and temperatures as in high-power electric vehicles. In such cases, passive balancing could be sufficient for maintaining the balance of the cells in the pack.</li><li>Second-life batteries: When used batteries from <a href="https://cellsaviors.com/blog/salvaged-lithium">salvaged battery packs</a>, after their first life as energy storage, are used in less demanding applications, passive balancing could be an option.</li><li>Cost-sensitive applications: Passive balancing is generally less expensive to implement than active balancing, therefore if cost is a major concern, passive balancing could be a viable option in electric vehicle applications.</li></ul> It's important to keep in mind that in general, electric vehicles require high accuracy and fast response times to ensure the safety and performance of the battery pack. Therefore, passive balancing may not be the best choice in most electric vehicle applications, but in some specific use cases, it could be a viable option.<h3>Conclusion</h3>Balancing is one of the most important aspects of lithium-ion batteries. This is because lithium-ion battery packs contain multiple groups of <a href="https://cellsaviors.com/blog/series-vs-parallel">cells in parallel and series</a>. The parallel cells are able to transfer energy between each other and maintain a self-balance, but the series cells cannot do this.This is why some sort of external balancing circuit is required. In an ideal scenario, you would not have to worry about balance because the cells are all the same anyway. In reality, however, variations in the manufacturing process and other factors will make even batteries with perfectly matched cells eventually come out of balance.&nbsp;Active balancing is able to redistribute energy between the series groups of a battery pack to ensure that they all have the same state of charge. This is done with a sophisticated circuit that is able to connect to the higher voltage cell group, take the excess energy from it, connect to a lower voltage cell group, and then transfer the stored energy to them to bring them into balance. Because of this, active balancing is the more accurate and faster approach to battery balancing.In contrast, passive balancing relies on Ohm’s Law and the natural cell and balance resistor characteristics to bring cells to the same state of charge. This method works by literally burning off the excess energy in the higher voltage cell groups, which is wasteful. Because of this, passive balancing is generally less accurate and slower than active balancing and in cases where the cell groups are significantly imbalanced, the low and slow passive balance current may be totally unable to bring the battery to balance.&nbsp;We hope this article helped you learn everything you needed to know about the difference between active and passive balancers. Thanks for reading!

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