AGM vs Lithium

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. 

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. 

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. 

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 convert something from lead acid to lithium.

Comparison of AGM and Lithium Battery Characteristics

Lithium Batteries

Pros:

• Lightweight and compact
• High energy density
• Longer lifespan
• Fast charging capabilities
• Wide operating temperature range
• Low self-discharge rate

Cons:

• Higher upfront cost compared to AGM or lead acid batteries
• Specialized CC/CV (Constant Current/Constant Voltage) charger required
• Potential safety concerns if damaged or improperly designed or used
• Limited availability in some regions

AGM / Lead Acid Batteries

Pros:

• Lower upfront cost compared to lithium batteries
• Widely available
• More robust and durable than lithium batteries
• No special charging equipment required

Cons:

• Far heavier and much larger than lithium batteries
• Lower energy density compared to lithium batteries
• Shorter lifespan compared to lithium batteries
• Slower charging capabilities compared to lithium batteries
• Higher self-discharge rate compared to lithium batteries
• Higher TCO (Total Cost of Ownership)

AGM vs Lithium - Capacity and Power Output

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.

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 specific energy of around 90 to 165 Wh/L, 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. 

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. 

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. 

Lifespan and Durability of AGM vs Lithium

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.  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 cycles and life out of lithium batteries 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, having the right BMS 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. 

The Charging and Maintenance Requirements of AGM Compared To Lithium

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. 

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.

AGM vs Lithium Cost Comparison

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.

Environmental Impact of AGM and Lithium Batteries

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. 

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 salvaging thrown-out lithium battery packs for reuse. 

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.

When To Use AGM vs Lithium Batteries

Use an AGM battery for:

• Backup power systems
• Applications that require a wide operating temperature range
• Standby power for essential services
• Applications that require a reliable source of power for short periods of time

Use a Lithium battery for:

• Electric vehicles and other high-performance applications
• Portable devices, such as laptops and smartphones
• Applications that require fast recharge times
• Applications that require high energy density
• Applications that require a long lifespan.

When To Not Use AGM vs Lithium Batteries

Don't use an AGM battery with:

• Applications that require fast recharge times
• Applications that require high energy density
• Applications that require a long lifespan

Don't use a Lithium battery with:

• Applications that require an extremely low upfront cost

Conclusion: Choosing the Right Battery for Your Needs.

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!