creating-a-simple-battery-level-indicator

Discover how to make a simple battery level indicator using an ESP32 microcontroller, a voltage divider, and LEDs. This easy-to-follow guide will walk you through each step to create an effective tool for monitoring your battery's power levels.

Guide to Making a Simple Battery Level Indicator

In the world of electronics, monitoring a battery's level is a critical part of the process. There are several ways to achieve this, but one particularly efficient way is to use an ESP32 microcontroller, a voltage divider, and a set of LEDs. This article will guide you through the process of building a basic yet effective <a href="https://cellsaviors.com/blog/understanding-battery-level-indicators">battery level indicator</a> using these components.<h2>Using ESP32 Microcontroller for Battery Voltage Level</h2>The ESP32 is a versatile microcontroller with numerous features, one of which is its ability to read analog voltages through its analog pins. These pins can read voltages in the range of 0 to 3.3 volts. However, it's important to understand that the ESP32 does not directly output the voltage value in its readings. Instead, it converts the analog voltage into a digital value ranging from 0 to 4095, based on its 10-bit Digital-to-Analog Converter (DAC).For example, a reading of 4095 corresponds to 3.3 volts, while a reading of 2048 represents approximately 1.66 volts, which is half of 3.3 volts. This conversion is crucial for understanding how to interpret the signals from the ESP32. One noteworthy point is that the ESP32’s analog-to-digital conversion is known to be nonlinear, especially at lower voltage levels, which can be a consideration in precision-dependent applications. For this application, however, it won't be a problem at all.&nbsp;<h3>The Need For a Voltage Divider</h3>To <a href="https://cellsaviors.com/blog/battery-capacity-test">measure battery voltages</a>, especially those higher than 3.3 volts (such as a fully charged single cell at 4.2 volts), a voltage divider is essential to prevent damage to the microcontroller. A voltage divider is a simple circuit element that divides the input voltage based on the ratio of two resistors. It consists of an input, output, and ground connection.In a basic setup with two equal resistors, the voltage divider would halve the input voltage. For example, if you input 12 volts, the output in the middle of the two resistors would be 6 volts. This division is based on Ohm’s law, with the voltage split according to the resistors' proportions.<h3>Designing a Voltage Divider for Higher Voltages</h3>For applications requiring the monitoring of higher battery voltages, such as up to 84 volts, the resistance ratio in the voltage divider needs to be adjusted accordingly. After some experimentation, it’s determined that a top resistance of 242 kilo-ohms and a bottom resistance of 10 kilo-ohms yields a maximum output voltage of about 3.27 volts, which is within the safe reading range of the ESP32.<h3>Implementing the Battery Level Indicator</h3>To create a basic program for controlling the four status LEDs based on the battery level read by the ESP32, you'll follow several key steps. These include setting up the ESP32, reading the voltage, calculating the battery level, and then controlling the LEDs based on this level. Here's a guide to help you through the process:<ul><li>Setup and Initialization:<ul><li>Start by initializing the GPIO pins connected to the LEDs as output pins.</li><li>Initialize the analog pin connected to the voltage divider as an input pin.</li></ul></li><li>Reading Battery Voltage:<ul><li>Use the analogRead() function to read the voltage from the voltage divider.</li><li>Map this reading to the actual voltage using the formula actualVoltage = readValue * (3.3 / 4095).</li><li>Adjust this formula based on your voltage divider's specific scaling factor to get the real battery voltage.</li></ul></li><li>Calculating Battery Percentage:<ul><li>Determine the voltage levels corresponding to 25%, 50%, 75%, and 100% of your battery's capacity.</li><li>Convert these voltage levels to their respective ADC readings.</li><li>Compare the current reading with these thresholds to determine the battery level.</li></ul></li><li>Controlling the LEDs:<ul><li>Based on the calculated battery percentage, control the LEDs:<ul><li>0-25%: Turn on only the first LED.</li><li>26-50%: Turn on the first two LEDs.</li><li>51-75%: Turn on the first three LEDs.</li><li>76-100%: Turn on all four LEDs.</li></ul></li></ul></li><li>Loop:<ul><li>Continuously read the battery voltage and update the LED status accordingly.</li></ul></li><li>The Code:</li></ul>Here's a basic outline of what your Arduino battery level code might look like:// Define LED and analog pinint ledPins[] = {5, 18, 19, 21}; // Replace with your ESP32 GPIO pin numbersint analogPin = 34; // Replace with your analog pin numbervoid setup() {&nbsp; // Initialize LED pins as output&nbsp; for (int i = 0; i &lt; 4; i++) {&nbsp; &nbsp; pinMode(ledPins[i], OUTPUT);&nbsp; }&nbsp; // Initialize analog pin as input&nbsp; pinMode(analogPin, INPUT);}void loop() {&nbsp; // Read battery voltage&nbsp; int value = analogRead(analogPin);&nbsp; float batteryVoltage = map(value, 0, 4095, 0, 84); // Map the analog reading to a voltage between 0 and 84 volts&nbsp; // Determine battery level&nbsp; int batteryLevel = calculateBatteryLevel(batteryVoltage);&nbsp; // Update LEDs based on battery level&nbsp; updateLEDs(batteryLevel);&nbsp; // Add a delay for stability&nbsp; delay(1000);}int calculateBatteryLevel(float voltage) {&nbsp; if (voltage &gt;= 80.0 &amp;&amp; voltage &lt;= 84.0) {&nbsp; &nbsp; return 3; // 80V - 84V (4 bars)&nbsp; } else if (voltage &gt;= 75.0 &amp;&amp; voltage &lt; 80.0) {&nbsp; &nbsp; return 2; // 75V - 79.9V (3 bars)&nbsp; } else if (voltage &gt;= 70.0 &amp;&amp; voltage &lt; 75.0) {&nbsp; &nbsp; return 1; // 70V - 74.9V (2 bars)&nbsp; } else if (voltage &gt;= 58.0 &amp;&amp; voltage &lt; 70.0) {&nbsp; &nbsp; return 0; // 58V - 69.9V (1 bar)&nbsp; } else {&nbsp; &nbsp; return -1; // Invalid voltage&nbsp; }}void updateLEDs(int level) {&nbsp; for (int i = 0; i &lt; 4; i++) {&nbsp; &nbsp; if (i &lt;= level) {&nbsp; &nbsp; &nbsp; digitalWrite(ledPins[i], HIGH);&nbsp; &nbsp; } else {&nbsp; &nbsp; &nbsp; digitalWrite(ledPins[i], LOW);&nbsp; &nbsp; }&nbsp; }}<h2>ESP32 Battery Level Monitor Limitations</h2>The ESP32 microcontroller, while a versatile and powerful tool for various projects, does have some limitations when it comes to its Analog-to-Digital Converter (ADC) pins. Understanding these limitations is crucial for applications where precise analog voltage measurements are essential.<h3>Non-Linearity of ESP32 ADC Pins</h3> The ADC of the ESP32 is known for its non-linear behavior, especially at lower voltage levels. This means that the conversion of analog voltage to digital values is not a straightforward linear process. For example, at lower voltages, the increment in digital values might not correspond proportionately to the increment in actual voltage. This irregularity can cause inaccuracies in measurements.<h3>Impact on The Battery Level Indicator</h3>In the context of creating a battery level indicator, this non-linearity implies that the voltage readings might not be entirely precise but it will be just as accurate as any other basic 4-dot display indicating general battery levels (such as 25%, 50%, 75%, and 100%). This degree of accuracy is more than enough for most applications.&nbsp;<h3>Overcoming The Limitations</h3>For applications requiring more accurate voltage readings, using an external ADC like the ADS1115 instead of the ESP32's built-in ADC is advisable.Higher Precision: The ADS1115 is a 16-bit ADC, offering significantly higher precision compared to the ESP32's 10-bit ADC. This means it can detect finer variations in voltage, leading to more accurate readings.Linear Response: The ADS1115 tends to have a more linear response across its entire range. This characteristic ensures that the conversion from analog to digital is more consistent, thereby providing more reliable readings.Application in Battery Monitoring: When precision in battery voltage measurement is crucial, integrating an ADS1115 with the ESP32 for your battery level indicator project can yield much more accurate results. This is especially relevant in scenarios where battery voltage needs to be monitored with high accuracy, such as in critical power management systems.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image&quot;,&quot;height&quot;:285,&quot;url&quot;:&quot;https://lh7-us.googleusercontent.com/bTmcnFIsl8FxYeuu3E-PTht7afiurpdEc9mxmOf7YpPTeCvb1BoMjNhFnvWr0AyavQhQIOfbfdkWv4JzCO8Tfmq3fMx22bNKCpM0LHtZqIelsfiaFe5qvFfn2euOXmkelMOFp2VgxGlkfr6rLoOqXKI&quot;,&quot;width&quot;:568}" data-trix-content-type="image" class="attachment attachment--preview"><img src="https://lh7-us.googleusercontent.com/bTmcnFIsl8FxYeuu3E-PTht7afiurpdEc9mxmOf7YpPTeCvb1BoMjNhFnvWr0AyavQhQIOfbfdkWv4JzCO8Tfmq3fMx22bNKCpM0LHtZqIelsfiaFe5qvFfn2euOXmkelMOFp2VgxGlkfr6rLoOqXKI" width="568" height="285"><figcaption class="attachment__caption"></figcaption></figure>Battery Level Meter, Honestly Just Buy OneBefore making one of these, it's important to consider the practical aspects. In the realm of electronics, especially for hobbyists and DIY enthusiasts, the balance between <a href="https://cellsaviors.com/blog/building-a-battery-pack-from-18650-cells">building a DIY battery pack</a> and purchasing a prebuilt is is important to consider. When it comes to battery level indicators, this decision becomes particularly relevant due to the wide availability and affordability of pre-made options on the market. For example with large home-based battery systems, you can look at several <a href="https://cellsaviors.com/blog/powerwall-monitor">powerwall monitoring</a> options and there is no reason these devices couldn't be used on other batteries.Cost-Effectiveness: One of the primary reasons to opt for a pre-made battery level indicator is cost. These devices are often available at a fraction of the cost of sourcing individual components like the ESP32, resistors, and LEDs. The economies of scale in manufacturing allow these products to be sold at very competitive prices.Variety and Features: The market is flooded with a myriad of battery level indicators, each offering different features and specifications. From basic LED displays to more sophisticated ones with LCD or OLED screens, the choices are abundant. This variety allows users to find a product that closely matches their specific needs and preferences.Time and Effort: Building a battery level indicator from scratch, while educational and fulfilling, requires a significant investment of time and effort. For those who need a quick and efficient solution without the learning curve or the time spent in assembly and troubleshooting, buying a pre-made indicator is a sensible choice.<h3>Conclusion</h3>Creating a simple battery level indicator with an ESP32, a voltage divider, and four LEDs offers a practical and efficient way to monitor battery power levels. By applying the principles of voltage division and leveraging the ESP32's ADC capabilities, users can accurately determine the remaining power in their batteries. The detailed explanation of Ohm's law, along with the step-by-step guide for setting up the voltage divider, makes the process accessible even to beginners.Also, the provided code simplifies the implementation, allowing enthusiasts and hobbyists to easily build and integrate this indicator into their projects. This project not only serves as a functional tool but also illustrates the versatility and capability of the ESP32 in creating practical electronic devices.&nbsp;

How Do You Make a Simple Battery Level Indicator

Learn the right way to hook up dual batteries to enhance power and lifespan in vehicles, boats, and bikes, while ensuring safety and compatibility.

Guide to Hooking Up Dual Batteries

Hooking up dual batteries is a common procedure in various applications, including vehicles, boats, and electric bikes. The process can enhance the capacity, stability, and longevity. However, it's important to understand the correct methods to connect dual batteries to avoid potential risks and ensure efficient performance. You essentially have two options, <a href="https://cellsaviors.com/blog/series-vs-parallel">putting them in parallel or in series</a>.<h2>Understanding Battery Basics</h2>Before getting into the methods of <a href="https://cellsaviors.com/blog/dual-battery-ebike">connecting dual batteries</a>, it's important to grasp some fundamental concepts about batteries. A great example of how beneficial this can be is hooking up dual batteries on your ebike; you can double your range. The two critical factors to consider when pairing batteries are voltage and capacity. Voltage refers to the electrical potential difference, while capacity is about the amount of charge a battery can hold. Ensuring that the batteries you intend to connect have similar voltages and capacities is crucial for a safe and effective setup.<h2>Hooking Dual Batteries Up in Parallel</h2>The simplest method to <a href="https://cellsaviors.com/blog/parallel-lithium-batteries">connect two batteries is in parallel</a>. This approach is ideal when the batteries have the same voltage and capacity and are in a similar condition. To hook up batteries in parallel, connect the positive terminal of one battery to the positive terminal of the other and do the same with the negative terminals. This configuration doubles the capacity while keeping the voltage the same.However, a critical aspect to consider is the voltage difference between the batteries. They should be within 0.1 volts of each other before connection. If there's a significant voltage difference, a large, unregulated current might flow from the higher-voltage battery to the lower one, causing a rapid and potentially dangerous discharge and charge process.<h2><figure data-trix-attachment="{&quot;contentType&quot;:&quot;image&quot;,&quot;height&quot;:233,&quot;url&quot;:&quot;https://lh7-us.googleusercontent.com/MFw2R9HfaSVDfdii_wXmQTAEG2DOe4upy-erAoVRyDwmMtgdq2995MDVQ_EYUCMGdJAhyS89Bt9A6fMZ_EyN3XhIV1j1S4cRPH83vwkS6IWBOw2PfYQfTLnIySoLsEZzR85FMI_0lR5_ooCxEoimtQI&quot;,&quot;width&quot;:464}" data-trix-content-type="image" class="attachment attachment--preview"><img src="https://lh7-us.googleusercontent.com/MFw2R9HfaSVDfdii_wXmQTAEG2DOe4upy-erAoVRyDwmMtgdq2995MDVQ_EYUCMGdJAhyS89Bt9A6fMZ_EyN3XhIV1j1S4cRPH83vwkS6IWBOw2PfYQfTLnIySoLsEZzR85FMI_0lR5_ooCxEoimtQI" width="464" height="233"><figcaption class="attachment__caption"></figcaption></figure>Hooking Dual Batteries Up in Series</h2>When <a href="https://cellsaviors.com/blog/balance-lithium-batteries-series">connecting two batteries with a Battery Management System (BMS) in series</a>, extra caution is needed. The BMS in each battery is designed to manage charging and discharging, as well as ensure cell balance and temperature control. However, in a <a href="https://cellsaviors.com/blog/series-lithium-batteries">series configuration</a>, where the voltages of the batteries combine, the failure of one battery can pose a significant risk. For example, if two 12V batteries are linked in series, the total voltage is 24V. Should one battery fail, this entire voltage could be applied across the MOSFETs in the dead battery's BMS, potentially exceeding their voltage ratings and leading to failure.Exceeding the MOSFETs' voltage limits can cause serious issues, ranging from malfunction to severe cases like overheating or thermal runaway. It's important to regularly monitor the health and state of charge of each battery. Using batteries of similar age, capacity, and wear can help ensure they degrade at a similar rate, reducing the risk of one battery failing prematurely in the series arrangement. Deep discharges should be avoided to further minimize the likelihood of battery failure.To enhance safety and reliability, consider using additional protective circuitry or a BMS designed for series connections capable of handling the combined voltage. Alternatively, selecting batteries and BMS units specifically designed for series use can provide built-in safeguards against these risks. By adhering to these precautions, the integrity and <a href="https://cellsaviors.com/blog/lithium-cell-battery-safety">safety of the battery system</a> can be substantially improved.<h2>Using a Constant Current Boost Converter</h2>Another method to connect dual batteries, especially when they have different voltages, is through a constant current boost converter. This technique is particularly useful for applications like electric bikes, where you might have a primary 48-volt battery and a secondary 24-volt auxiliary battery.In this setup, you place a constant current boost converter between the lower voltage (24-volt) battery and the higher voltage (48-volt) battery. You can set the converter to a specific current, say 4 amps. As the primary battery is used, the secondary battery will continuously charge it, effectively increasing the range and reducing voltage sag. The boost converter elevates the lower voltage of the auxiliary battery to match the primary battery, ensuring a steady and safe power supply.<h2>Implementing a Constant Current Buck Converter</h2>Conversely, a constant current buck converter can be used when you want to step down the voltage from a higher voltage battery to supplement a lower voltage battery. This method is less common but can be effective in specific scenarios.For example, if you have a 36-volt main battery and a 48-volt auxiliary battery, you can use a constant current buck converter to reduce the voltage from the secondary battery to charge the primary one. This method helps maintain the charge of the lower voltage battery, ensuring that it contributes effectively to the overall power supply.<h2>Safety and Maintenance Considerations</h2>When hooking up dual batteries, safety is obviously super important. Always ensure that the batteries are in good condition and that the connections are secure. Regularly check the batteries for signs of wear, corrosion, or damage. It's also important to <a href="https://cellsaviors.com/blog/lithium-battery-charging">use compatible chargers</a> and converters designed for the specific type of batteries you are using. And remember, if you are connecting batteries in parallel, make sure they are at the same voltage before you connect them!

How Do You Hook Up Dual Batteries

Discover the main reasons behind Battery Management System (BMS) failures, from design flaws to misconfiguration. Learn how to prevent these issues and keep your battery systems running smoothly.

BMS Failure Common Causes and Signs

A BMS failure can stem from a variety of issues, from poor design and misconfiguration to external factors related to battery cell types and their arrangement. By understanding these causes and taking preventative measures, we can ensure the longevity and reliability of our battery-powered systems, keeping our devices running smoothly and safely.Battery Management Systems (BMS) are the unsung heroes of the battery world, ensuring our devices and vehicles run smoothly by managing the battery's charge, discharge, and <a href="https://cellsaviors.com/blog/testing-and-grading-lithium-ion-cells">overall health</a>. However, like any other component, a BMS can fail, and understanding why can help us prevent future failures. Failure doesn't always mean a catastrophic event; it could be as simple as the BMS no longer performing one of its key functions, such as cell balancing or enabling battery charging. Let's dive into what causes these critical systems to fail, distinguishing between simpler, "non-smart" BMS and their more complex, "smart" counterparts.<h2>Common Failures by BMS Type: Simple vs. Smart</h2><h3>Simple BMS Failures: Bad Design and Overrating</h3>At the heart of simpler, non-smart BMS failures are two main issues: poor design and overrating their capabilities. A poorly designed BMS might be sold with claims it can handle more current than it truly can, leading to overheating and failure. For example, a BMS advertised to handle 20 amps of charge current may only have a single MOSFET (Metal Oxide Semiconductor Field Effect Transistor) capable of managing 6 amps. This <a href="https://cellsaviors.com/blog/fake-battery-signs">discrepancy between marketing claims and reality</a> can lead to failures when the BMS is pushed to its advertised limits, resulting in overheated MOSFETs and eventual system failure. Also, if the cells managed by the BMS are too far out of balance, the passive balancing capabilities of a simpler BMS may not be sufficient. That can lead to the cells going drastically out of balance. That, of course, isn’t exactly the fault of the BMS, but it does highlight its <a href="https://cellsaviors.com/blog/active-passive-balancing">limitations of passive balancing</a>.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image&quot;,&quot;height&quot;:294,&quot;url&quot;:&quot;https://lh7-us.googleusercontent.com/Oah7inocrU3_X16oFLqVM7vUUeya_0c6SYhqNmAicK2qKTX6JLfzQd8bAXFm5OweQCoS2Qy3hvp-wLs-FizR7YF_8ncwUlOHPst5Ii_PNw3xI9P4vNpX9pISDRV9eQ5yTmgX0E-u1PILfmIGZdALWDQ&quot;,&quot;width&quot;:587}" data-trix-content-type="image" class="attachment attachment--preview"><img src="https://lh7-us.googleusercontent.com/Oah7inocrU3_X16oFLqVM7vUUeya_0c6SYhqNmAicK2qKTX6JLfzQd8bAXFm5OweQCoS2Qy3hvp-wLs-FizR7YF_8ncwUlOHPst5Ii_PNw3xI9P4vNpX9pISDRV9eQ5yTmgX0E-u1PILfmIGZdALWDQ" width="587" height="294"><figcaption class="attachment__caption"></figcaption></figure><h3>Smart BMS Failures: Misconfiguration and Power Draw</h3>Moving on to the more complex, smart BMS, these systems offer configurability and the ability to handle more current. However, this sophistication comes with its own set of challenges. Misconfiguration is a common pitfall; for instance, setting a BMS to handle a discharge current higher than its capabilities can lead to burnt-out MOSFETs and system failure. Additionally, smart BMSs tend to draw more power than their simpler counterparts. If a battery is left unused for extended periods, the continuous power draw of a smart BMS can deplete the battery to levels where the <a href="https://cellsaviors.com/blog/wake-up-bms">BMS can no longer function, essentially "putting it to sleep."</a> This state, while reversible, renders the battery useless unless addressed.<h2>BMS Failure Contributing Factors</h2>It's also important to consider the battery cells themselves and their configuration. Different <a href="https://cellsaviors.com/blog/safest-chemistry-cells">cell types have various disadvantages and safety profiles</a> that can impact BMS performance. For instance, pouch cell batteries are known for their fragility and risk of explosion, factors that can complicate BMS management. Similarly, how cells are configured, such as in series or parallel arrangements, can influence the BMS's effectiveness and risk profile. For example, <a href="https://cellsaviors.com/blog/series-lithium-batteries#google_vignette">connecting lithium batteries in series</a> without considering the BMS's capabilities can lead to over-volting and failure​​.<h2>Preventing BMS Failure</h2>Understanding <a href="https://cellsaviors.com/blog/bms-lithium-batteries">how to choose the right BMS</a>, its limitations and proper configurations are super important in preventing failures. For simpler BMS, ensuring the system is not overstressed and that cells are well-balanced is key. For smart BMS, proper configuration according to the manufacturer's specifications and <a href="https://cellsaviors.com/blog/testing-and-grading-lithium-ion-cells">regular monitoring to prevent deep discharge</a> are vital steps. Additionally, <a href="https://cellsaviors.com/blog/pick-best-cells-battery">choosing the right type of battery cells</a>, considering their safety profiles and suitability for the application is paramount.We hope this article helped you learn all about what causes a BMS to fail, thanks for reading!

What causes BMS to fail

Is it better to store lithium batteries charged or uncharged

Find out how to store lithium-ion batteries properly to keep them working well. Learn why keeping them at a nominal voltage level is important to the health of the cell.

The Best Way to Store Your Lithium Batteries

Storing lithium-ion batteries at a charge level around their <a href="https://cellsaviors.com/blog/nominal-voltage">nominal voltage</a>, approximately 3.6 to 3.7 volts, is considered the optimal practice for extending their lifespan and maintaining performance. This middle-ground approach mitigates the risks associated with storing batteries at full charge, which can accelerate wear due to increased self-discharge rates, and the dangers of fully discharged, which can lead to irreversible damage in the event that voltage drops below a safe threshold.By storing batteries in this "Goldilocks zone", you ensure that they remain in a safe and stable state, which minimizes stress and <a href="https://cellsaviors.com/blog/lithium-batteries-degradation">degradation over time</a>. Additionally, it's crucial to store batteries away from extreme temperatures and humidity, regularly check their voltage, and use a smart charger to maintain them at the ideal storage charge, aligning with best practices for battery health and longevity.<h2>The Chemistry of Charge: To Store Charged or Not?</h2>When a lithium-ion battery is fully charged, it operates at its peak potential. For a single cell, this means a voltage of 4.2 volts, and for a 3S battery configuration, it equates to 12.6 volts. At this state, every cell, regardless of its make or age, undergoes a natural process known as internal self-discharge. This phenomenon is an inevitable consequence of the imperfect manufacturing processes of lithium-ion batteries, leading to minor energy transfers between the battery's positive and negative electrodes.<h3>The Problem with Storing Fully Charge</h3>As batteries age or sustain damage, the rate of self-discharge increases, significantly impacting performance. This degradation occurs because the internal resistance, which ideally should be infinitely high, is merely very high, allowing for some energy leakage based on the battery's voltage and resistance levels. <a href="https://cellsaviors.com/blog/lithium-battery-storage">Storing lithium batteries</a> at full charge exacerbates this issue by keeping cells at a more reactive voltage range than necessary, thus potentially accelerating wear.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image&quot;,&quot;height&quot;:288,&quot;url&quot;:&quot;https://lh7-us.googleusercontent.com/TGmi-Mh6lcSNMvAHTdxtsmPhUbsXtKPp4a4ah-TAVnrBVzfown-ah84sQVZ5WE4z5BbV5MAAK7OC6a7TfPnJ4We87AkoJIjhGnybDZxNQhD7wMyh_RkRVZpKfmbIE7i6EEXFf2zdlgUv8agC-csgkOg&quot;,&quot;width&quot;:573}" data-trix-content-type="image" class="attachment attachment--preview"><img src="https://lh7-us.googleusercontent.com/TGmi-Mh6lcSNMvAHTdxtsmPhUbsXtKPp4a4ah-TAVnrBVzfown-ah84sQVZ5WE4z5BbV5MAAK7OC6a7TfPnJ4We87AkoJIjhGnybDZxNQhD7wMyh_RkRVZpKfmbIE7i6EEXFf2zdlgUv8agC-csgkOg" width="573" height="288"><figcaption class="attachment__caption"></figcaption></figure><h3>The Risks of Storing Fully Discharged</h3>On the other hand, storing batteries in a fully discharged state (around 2.8 volts, near the low voltage cutoff) also poses risks. Over time, the battery's voltage naturally declines, and if left unchecked, can drop below safe thresholds, leading to irreversible damage. This is particularly problematic if the battery is left connected to any device, as even the slightest parasitic load can hasten voltage decline. It is possible to <a href="https://cellsaviors.com/blog/recover-low-voltage-cells-batteries">revive low voltage cells</a> but in some cases, you cannot, and in all cases, some internal damage will have taken place.<h2>The Goldilocks Zone: Storing at Nominal Voltage</h2>The consensus among battery experts suggests that the <a href="https://cellsaviors.com/blog/best-battery-storage-voltage">optimal storage voltage for lithium-ion batteries</a> lies just above their nominal voltage of 3.7 volts. Storing batteries at around 3.8 to 3.9 volts strikes a balance, ensuring that even after natural discharge, the battery remains within a safe voltage range conducive to long-term storage. This practice mitigates the risks associated with both full charge and complete discharge, ensuring the battery remains in a stable state.<h3>Why Nominal is Optimal</h3>At nominal voltage, lithium-ion batteries reside in the safest and most stable portion of their charge curve. This means that over time, the battery's voltage will likely settle in the vicinity of 3.7 volts, a level that poses minimal risk to the battery's health and longevity, assuming it's stored under appropriate conditions (away from direct sunlight and high humidity environments).<h2>Practical Tips for Battery Storage</h2>Avoid Extreme Conditions: Regardless of the charge level, always store your batteries away from extreme temperatures and humidity to prevent unnecessary stress and degradation. For more tips on keeping your batteries warm, check out <a href="https://cellsaviors.com/blog/lithium-batteries-warm">How To Keep Batteries Warm.</a>Regular Check-ups: Periodically check the voltage of stored batteries to ensure they remain within safe limits. This is especially crucial for batteries stored for extended periods.&nbsp;Consider Usage Plans: If you plan to use the battery soon, storing it closer to full charge may be practical. However, if long-term storage is intended, aim for the nominal voltage range to optimize longevity.&nbsp;Use a Smart Charger: Invest in a charger capable of setting specific voltages so that you can accurately bring your batteries to the ideal storage voltage. Take a look at our&nbsp;<a href="https://cellsaviors.com/blog/18650-21700-chargers-testers">Best Cell Tester And Chargers 18650/21700</a>&nbsp;article&nbsp;for some options of charges that will hold cells at storage voltage.By adhering to these guidelines, users can significantly extend the lifespan and maintain the performance of their lithium-ion batteries, ensuring they deliver reliable power when needed. Understanding and respecting the delicate chemistry of these batteries is key to maximizing their potential and safety.

Is It Better To Store Lithium Batteries Charged or Uncharged

Find out how battery level indicators tell us how much power is left, using easy-to-understand visuals. Learn how they work, even when the battery's power doesn't drop in a straight line, to keep us informed before we need to recharge

Understanding Battery Charge Level Indicators

When it comes to lithium-ion batteries, understanding the state of charge based on voltage alone is a bit like trying to find your way in the dark without a flashlight. Sure, you know if you're fully charged at <a href="https://cellsaviors.com/blog/min-max-voltage-18650">4.2 volts or empty at the low voltage cutoff around 2.8 volts</a>, but the journey between these two points? That's where it gets murky.A Lithium-ion battery’s voltage does not simply fall linearly. Instead, its voltage drops pretty quickly when being used from a full charge. Then, it reaches somewhat of a plateau where the voltage drops slowly. Then, at the end of the discharge curve, the voltage falls rapidly again. This makes it a bit tricky to nail down the exact percentage of charge left just by looking at the voltage.&nbsp;Also, you can probably tell how charged your ebike is just by how it performs when accelerating. It's like trying to guess the RPM of your engine by how it sounds; you can get a rough idea, but wouldn't a tachometer be a more reliable indicator? If you're interested in constructing your own bike battery, you check out our guide on <a href="https://cellsaviors.com/blog/build-ebike-battery">How To Build A Lithium Ion Ebike Battery</a>.This is where battery level indicators come into play, acting as our much-needed gauge. These clever little devices give us a visual or numerical representation of how much juice we've got left before needing a recharge. But if the voltage curve of lithium-ion batteries is as nonlinear as a mountain road, how do these indicators manage to give us a reading?<h2>Battery Level Indicator: Simplification Tactic</h2>Most battery level indicators sidestep the complex reality of voltage curves by pretending things are simpler than they are. They operate under the assumption that the battery's voltage drops linearly with use. While this method is not perfectly accurate. For example, it may indicate a 50% charge when your battery might actually be somewhere between 30% to 60%. Even considering this limitation, a simple solution like this is surprisingly effective for most practical purposes.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image&quot;,&quot;height&quot;:303,&quot;url&quot;:&quot;https://lh7-us.googleusercontent.com/yaVeauW_lzi0JAZNFC63fCQvRnECUPy42bddag_lsatnUMH8hWjV1A0molWsQqYLd7lEScftrGRjN2eBMqieLDg2Ly2Ac31tIw0WvUvfjZ063cWnj_zi6xYta0kEVrdfhV3N6N_NvjmusAE7SqGvlAY&quot;,&quot;width&quot;:624}" data-trix-content-type="image" class="attachment attachment--preview"><img src="https://lh7-us.googleusercontent.com/yaVeauW_lzi0JAZNFC63fCQvRnECUPy42bddag_lsatnUMH8hWjV1A0molWsQqYLd7lEScftrGRjN2eBMqieLDg2Ly2Ac31tIw0WvUvfjZ063cWnj_zi6xYta0kEVrdfhV3N6N_NvjmusAE7SqGvlAY" width="624" height="303"><figcaption class="attachment__caption"></figcaption></figure>These indicators use the battery's voltage and map it out across a series of LEDs or other display elements. Each LED represents a specific charge level milestone such as 25%, 50%, 75%, and so on. Some indicators might get a bit more sophisticated, using colors or varying the number of lights to give a more granular look at the battery's state.<h2>Beyond Simple Voltage Reading: Coulomb Counting</h2>For those seeking precision, there's a more advanced technique called coulomb counting. This method doesn't just consider the voltage; but it also takes into account the current flowing in and out of the battery, calculating the total charge transferred over time. By tracking how many "coulombs" of charge have been used or replenished, these indicators can offer a much more accurate picture of the battery's state of charge.Coulomb counting requires a bit of digital brainpower, typically in the form of a microcontroller, and some custom algorithms to account for the battery's behavior. It's like having a smart fuel gauge that learns how your car consumes gas over different routes and adjusts its readings accordingly.<h2>The Truth About Battery Guages</h2>No matter the method, it's super important to understand that all battery level indicators are approximations. The very nature of <a href="https://cellsaviors.com/blog/best-battery-chemistry#google_vignette">battery chemistry</a>, combined with the variety of use cases and conditions, means that achieving perfect accuracy is a tall order. Even the highest-end indicators require calibration and adjustment at some point.<h2>How to Make Your Own Battery Level Indicator</h2>For the DIY enthusiasts and tech tinkerers out there, <a href="https://cellsaviors.com/blog/creating-a-simple-battery-level-indicator">making your own battery level indicator</a> can be a rewarding project. It offers a hands-on way to understand the principles we've discussed and apply them to real-world applications. Whether you're looking to create a simple LED display or dive into the world of coulomb counting, there's a wealth of resources and guides available to help you get started.&nbsp;One such guide we've prepared walks you through the process of creating a battery level indicator tailored to your needs. Whether you're aiming for simplicity or precision, our guide offers step-by-step instructions, tips for selecting the right components, and insights into the underlying science behind battery charge monitoring. Explore more do-it-yourself ideas from our articles, like <a href="https://cellsaviors.com/blog/diy-powerwall#google_vignette">building your own Powerwall</a>, <a href="https://cellsaviors.com/blog/diy-bench-power-supply">crafting an adjustable bench power supply</a>, <a href="https://cellsaviors.com/blog/plan-portable-power-pack">creating a portable power pack/station</a>, and <a href="https://cellsaviors.com/blog/diy-power-bank">building your own power bank</a>Understanding how a battery level indicator works demystifies one of the many small wonders of our electronic world. By translating the complex behavior of lithium-ion batteries into something we can easily read, these indicators help us manage our devices more effectively, ensuring we're never caught off guard by a dead battery.For those interested in taking matters into their own hands, building a battery level indicator is a great way to deepen your understanding of battery technology and electronics. So why not check out our guide on how to make a battery level indicator and embark on your next DIY project? Explore more do-it-yourself ideas from our articles, like <a href="https://cellsaviors.com/blog/diy-solar-system">setting up a home solar power system</a> and <a href="https://cellsaviors.com/blog/lithium-charger-diy">assembling a lithium battery charger</a>.

How Does a Battery Level Indicator Work

Learn how to make a simple solar system at home with our guide. We cover all components and assembly processes, from traditional to basic setups.

Easy Steps to Make a Home Solar System

Building a simple solar system at home can be both a rewarding and sustainable project, offering you a glimpse into renewable energy generation.&nbsp; This article will guide you through the process of assembling both a traditional small solar setup and a very basic, limited solar system, ensuring that the information is accessible and straightforward. You can also check out our more detailed guide on <a href="https://cellsaviors.com/blog/diy-solar-system">building a DIY solar system</a> for more comprehensive insights and tips.<h2>Traditional Simple Solar Setup Components</h2>For those looking to harness the sun's power more substantially, a small traditional solar system can be the way to go. Here's what you'll need:<ul><li>Solar Panels: Aim for multiple panels, each with at least 100 watts capacity, totaling a minimum of half a kilowatt. Ideally, you should target at least a kilowatt of usable power.</li><li>Charge Controller: Essential for managing the power flow from the panels to the battery and preventing overcharging. There are two main types:<ul><li>PWM (Pulse Width Modulation): More straightforward and cost-effective, suitable for simple systems.</li><li>MPPT (Maximum Power Point Tracking): More efficient but complex, optimizing the power output by adjusting the electrical current.</li></ul></li><li>Battery Bank: To store the energy collected by your solar panels. Lithium-ion batteries are recommended for their efficiency and compact size, although they require <a href="https://cellsaviors.com/blog/bms-lithium-batteries">a BMS (Battery Management System)</a> for safe operation.</li><li>Inverter: Converts DC electricity from your solar panels and battery into AC electricity, usable by most household appliances.</li><li>Wiring/Cabling: To connect all components safely and efficiently.</li></ul>If you want to make a simple solar system at home, understanding the nuances of each component—from solar panels' capacity to the technical specs of charge controllers and batteries—is super important. The right setup not only maximizes energy capture but also ensures a stable, efficient power supply for various needs.<h2>Basic Solar Setup Components</h2>For those who prefer simplicity or have limited needs, a very basic solar system can be assembled with fewer components:<ul><li>Smaller Scale Solar Panels: Fewer and possibly less powerful panels, depending on your energy needs.</li><li>Simplified Charge Controller: A <a href="https://cellsaviors.com/blog/mppt-pwm-solar-charge-controller">PWM controller or even a MPPT</a> compatible regulator could suffice for basic needs, directly connecting the solar panels to the battery.</li><li>Smaller Battery Bank: A smaller lithium-ion battery. It doesn’t have to be massive, just large enough to store a kilowatt-hour or two of energy.</li><li>Direct Usage: Instead of converting to AC, power DC appliances directly from the battery or use a simple DC to DC converter for necessary voltage adjustments. There are <a href="https://cellsaviors.com/blog/buck-boost-converters">two main types of converters</a> used for this purpose: a buck converter, which steps down the voltage, and a boost converter, which steps up the voltage to meet the requirements of different devices.</li></ul>This minimalist solar configuration exemplifies how the adoption of renewable energy can be accessible and adaptable, catering to the unique needs and constraints of individuals who wish to embrace a more sustainable lifestyle with a straightforward and efficient solar solution.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/jpeg&quot;,&quot;filename&quot;:&quot;assembly-and-safety.jpg&quot;,&quot;filesize&quot;:52946,&quot;height&quot;:370,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/YXPC7brZHBvLeYCaBMaYg8gTQq305kgDlK5Qut10.jpg&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/YXPC7brZHBvLeYCaBMaYg8gTQq305kgDlK5Qut10.jpg&quot;,&quot;width&quot;:736}" 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/YXPC7brZHBvLeYCaBMaYg8gTQq305kgDlK5Qut10.jpg"><img src="https://admin.cellsaviors.com/storage/YXPC7brZHBvLeYCaBMaYg8gTQq305kgDlK5Qut10.jpg" width="736" height="370"><figcaption class="attachment__caption">assembly-and-safety.jpg 51.71 KB</figcaption></a></figure><h2>Solar System Assembly and Safety</h2><ul><li>Mounting Solar Panels: Place your solar panels in a sunny location, ensuring they are securely mounted and angled to capture the maximum amount of sunlight. Additionally, it is important to <a href="https://cellsaviors.com/blog/clean-solar-panels">keep your solar panels clean</a> to maintain efficiency; dust, debris, and other obstructions can significantly reduce their performance.</li><li>Wiring: Connect your panels to the charge controller, which then connects to the battery bank. The inverter is then connected to the battery, converting DC to AC power for home use.</li><li>Safety Measures: Ensure all components are correctly rated for your <a href="https://cellsaviors.com/blog/how-to-size-wire-fuses-and-nickel-strip-for-a-lithium-battery-pack">system's voltage and current requirements</a>. Always follow the manufacturer's installation guidelines and consider professional help for complex setups.</li></ul>When you are making your simple solar system, attention to detail in the installation process can mean the difference between a totally successful project and something you end up regretting.<h3>Practical Tips</h3><ul><li>Energy Efficiency: Start with energy-efficient appliances to reduce your total power requirements as much as possible.</li><li>DC-DC:&nbsp;When possible use DC to DC power converting to AC comes with higher losses.&nbsp;</li><li>Maintenance: Regularly check and maintain your system to ensure optimal performance and longevity.</li></ul>Creating a simple solar system at home can be an enriching project, offering sustainability and independence from the grid. Whether you choose a traditional setup or a basic system, solar power provides a green alternative to conventional energy sources, reducing your carbon footprint and potentially saving on energy expenses.

How to Make a Simple Solar System At Home

38120 and 18650 cells are very different from each other in several ways, each has its place though, we go over that here!

18650 vs 38120 Cell Differences

18650 battery cells are commonly associated with NMC (Nickel Manganese Cobalt Oxide) chemistry, and 38120 battery cells are generally LFP (Lithium Iron Phosphate) chemistry. It's important to note that this isn't always the case. Compared to 18650 cells, 38120 cells can handle a lot more current. While it's true that 38120 cells commonly have capacities in the 8 to 9 amp-hour range, their size reduces their packing efficiency to the point where you will end up getting much more capacity using smaller 18650 cells.&nbsp;<h2>18650 Vs. 38120 Chemistry and Construction</h2><h3>18650: NMC Chemistry and Construction&nbsp;</h3>The 18650 battery, typically associated with NMC (Nickel Manganese Cobalt) chemistry, is a prevalent choice in numerous high-drain devices and applications, such as laptops, power tools, and electric vehicles. NMC batteries are celebrated for their high energy density, which allows them to store a substantial amount of energy in a relatively compact form. NMC chemistry cells have an extremely high packing efficiency, 3 of the <a href="https://cellsaviors.com/blog/highest-capacity-18650">highest capacity 18650 cells</a> would have more capacity than the 38120 cell at about 1/3rd or the space.&nbsp;This characteristic is particularly important in applications where space and weight are significant constraints. However, NMC chemistry is not perfect. One of its primary issues is thermal stability. Under extreme conditions, such as overcharging or high-temperature exposure, NMC batteries can present safety risks, including the potential for thermal runaway. This aspect necessitates careful management and protective measures to ensure safety in their use.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/jpeg&quot;,&quot;filename&quot;:&quot;38120 vs 18650 packing efficiency.jpg&quot;,&quot;filesize&quot;:72713,&quot;height&quot;:453,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/eP4b7Dn1eUuvIJAcBNYUXXLmxqJpd4GazLsWXV24.jpg&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/eP4b7Dn1eUuvIJAcBNYUXXLmxqJpd4GazLsWXV24.jpg&quot;,&quot;width&quot;:916}" 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/eP4b7Dn1eUuvIJAcBNYUXXLmxqJpd4GazLsWXV24.jpg"><img src="https://admin.cellsaviors.com/storage/eP4b7Dn1eUuvIJAcBNYUXXLmxqJpd4GazLsWXV24.jpg" width="916" height="453"><figcaption class="attachment__caption">38120 vs 18650 packing efficiency.jpg 71.01 KB</figcaption></a></figure><h3>38120: LFP Chemistry and Construction&nbsp;</h3>On the other hand, the 38120 battery is often linked with LFP (Lithium Iron Phosphate) chemistry. LFP batteries stand out for their exceptional robustness and inherent safety features. They are notably less susceptible to overheating and are characterized by higher thermal stability compared to their NMC counterparts.This makes them an ideal choice in scenarios where battery failure or malfunction could lead to severe consequences. LFP batteries are particularly favored in applications that demand high levels of reliability and safety, such as in some medical devices, <a href="https://cellsaviors.com/blog/diy-powerwall">DIY powerwalls</a>, and certain types of electric vehicles. Their resilience to temperature extremes and less reactive nature under stressful conditions contribute to their growing popularity in sectors where safety cannot be compromised.White 38120 only indicates the size of the cell and not the chemistry or brand, it's important to consider the fact that a company called Headway almost exclusively uses this format. So, when someone says <a href="https://cellsaviors.com/blog/38120-battery">‘Headway cells’ or ‘Headways’, they are talking about 38120 cells</a> that use LFP chemistry. One of the best things about Headway cells is the absolutely absurd amounts of current they can handle. These cells can do 120 amps each continuously and up to 240 amps for short amounts of time! This makes them favorable for uses like car audio battery banks, where there are large amounts of current outrush to power large amplifiers. They will also experience a large current inrush from the <a href="https://cellsaviors.com/blog/alternator-charge-lithium-battery">car alternator charging the battery bank</a>.<h2>18650 Vs. 38120 Assembly and Maintenance</h2><h3>18650: Welding Required</h3><a href="https://cellsaviors.com/blog/building-a-battery-pack-from-18650-cells">Assembling a battery pack with 18650 cells</a> typically requires <a href="https://cellsaviors.com/blog/spot-weld-battery">spot welding</a>. This is because soldering can damage the cells due to the high heat involved. Spot welding ensures a reliable connection while minimizing the risk of damaging the battery.<h3>38120: Simpler Assembly</h3>The 38120, on the other hand, can be assembled using nuts and bolts, making them more accessible for DIY projects and easier to maintain. This feature is particularly advantageous for users who prefer to assemble and repair their own battery packs without specialized equipment.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/jpeg&quot;,&quot;filename&quot;:&quot;headway cell assembly.jpg&quot;,&quot;filesize&quot;:99071,&quot;height&quot;:516,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/RqHUsQ4W3khJEr6kpeernV5s9L1dmqil3krjoaEI.jpg&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/RqHUsQ4W3khJEr6kpeernV5s9L1dmqil3krjoaEI.jpg&quot;,&quot;width&quot;:467}" 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/RqHUsQ4W3khJEr6kpeernV5s9L1dmqil3krjoaEI.jpg"><img src="https://admin.cellsaviors.com/storage/RqHUsQ4W3khJEr6kpeernV5s9L1dmqil3krjoaEI.jpg" width="467" height="516"><figcaption class="attachment__caption">headway cell assembly.jpg 96.75 KB</figcaption></a></figure><h2>18650 Vs. 38120 Performance Metrics</h2><h3>Capacity</h3>When it comes to capacity, the 18650 and 38120 batteries have different offerings. The 18650 typically has a capacity range that can cater to high-drain devices. However, the actual capacity can vary based on the specific chemistry and design of the cell.The 38120, while generally larger in volume than the 18650, does not always translate this into a proportionally higher capacity. This is largely due to the differences in the energy densities of NMC and LFP chemistries.<h3>Current Capability</h3>The current handling capability is where the 38120 really shines. LFP chemistry allows these cells to handle high current demands, making them ideal for applications like electric vehicles and large-scale energy storage, where rapid discharge and charging are common.On the other hand, while 18650 cells can handle significant currents, they are typically outperformed by 38120 cells in this aspect. This limitation is partly due to the NMC chemistry and the cell's physical size.<h3>Cycle Life</h3>The cycle life of a battery is a critical factor in determining its long-term value and suitability for certain applications. LFP cells, like the 38120, generally offer a longer cycle life compared to NMC cells, like the 18650. This is because LFP chemistry is more stable over repeated charging and discharging cycles. It's not uncommon for LFP cells to last for thousands of cycles before their capacity significantly degrades. With both cell types and chemistries you can <a href="https://cellsaviors.com/blog/get-more-cycles-from-lithium-ion-cells">increase cycle life</a> by employing some proactive measures.&nbsp;In contrast, 18650 cells, although they offer a high initial capacity, tend to have a shorter cycle life <a href="https://cellsaviors.com/blog/lithium-batteries-degradation">degrading quicker over time</a>. This means that over time, their ability to hold a charge diminishes faster compared to LFP cells.<h2>38120 vs 18650 Closing Thoughts</h2>When it comes to choosing between 38120 and 18650 batteries, the decision ultimately hinges on your specific needs. If you're prioritizing a compact and lightweight solution, 18650 batteries are the way to go. They offer a sleek and space-efficient design that's perfect for applications where every inch and ounce matter.On the other hand, if you require high serviceability and the ability to handle substantial current loads, 38120 batteries are the better choice. These larger batteries offer the advantage of robust performance and can tackle demanding tasks with ease, making them the preferred option when space constraints are not a concern. So, the choice boils down to your specific requirements and priorities in power solutions.

Differences Between 18650 vs 38120

Looking for the best cell or battery pack capacity testers for your project? We reviewed the best hobby grade testers we could find.

Best Lithium Battery Pack & Cell Capacity Testers

In the ever-evolving world of technology, batteries have become a cornerstone of our everyday devices. Whether it's for smartphones, laptops, or even electric vehicles, the need for reliable and efficient batteries is more crucial than ever. However, the key to harnessing the best performance from these power sources lies in understanding <a href="https://cellsaviors.com/blog/testing-and-grading-lithium-ion-cells">how to test capacity and overall health</a>.&nbsp;This is where <a href="https://cellsaviors.com/blog/battery-capacity-test">battery capacity testing</a> comes into play. Battery capacity testers are essential for anyone looking to gauge the performance of their batteries, especially for those operating under 5 volts or at higher voltages. In this article, we delve into some of the best battery capacity testers available in the market, tailored for different voltage requirements and packed with features to cater to a variety of testing needs.If you are looking for the best cylindrical cell format you can check out our article on <a href="https://cellsaviors.com/blog/18650-21700-chargers-testers">the best 18650 and 21700 testers</a>.<h2>Best Battery Capacity Testers For 5V and Under:</h2>These <a href="https://cellsaviors.com/blog/accurate-battery-test">battery testers are highly accurate tools</a> for testing single-cell prismatic batteries. They are brand new and widely used for this type of battery testing. Their robust performance is demonstrated by years of flawless operation in large testing cabinets with dozens of these units.<blockquote>[[ aff type=aff ~ link=`https://batteryhookup.com/discount/CS5?redirect=/products/zketech-ebc-a40l-capacity-tester-0-5v-40a-charge-discharge` ~ title=`Battery Cell Capacity Tester` ~ image=https://admin.cellsaviors.com/storage/battery-capacity-tester-5v.jpg ~ description=`Great for testing large-capacity single battery cells. Use our link to save 5% now! ` ~ height=small ~ buttonText=`Check Price`&nbsp; ]]</blockquote>Key Features:<ul><li>Programmability for full control and chart creation.</li><li>Capability to charge, discharge, and recharge, providing accurate battery capacity assessment.</li><li>Suitable for testing lithium batteries like LiFePO4.</li><li>Voltage range: 0-5 volts.</li><li>Current range: 0-40 amps.</li><li>Includes a USB adapter for computer connectivity.</li><li>Ability to save test parameters for easy access.</li><li>Equipped with 10 gauge wires, recommended for up to 30 amps for prolonged testing.</li><li>Ideal for testing at 0.2C rates (e.g., 8 amps for a 40Ah battery).</li></ul>Usage:These testers are versatile, allowing for both battery testing and charging. They are effective in capturing the performance characteristics of batteries, by providing a visual representation of charge and discharge curves. It's essential to conduct tests in a safe area, considering the inherent risks associated with battery testing.Power on the tester and connect the included USB adapter from the tester to your computer, then open the EB Tester software on your computer. In the 'Comm Setting', select the appropriate Com Port (usually between 3-9) and click 'connect'.Go to the 'Cycle Test' tab, then select 'Setting' at the bottom right of the screen. Program the steps and parameters of your test within the 0-5v and 0-40a range.Example for a 3.2v 100Ah LiFePO4 battery:Step 1: Set Mode as C-CV (Constant Voltage), Current at 20 amps, Voltage at 3.65v, Cutoff at 0.2 amps.Step 2: Choose Mode as D-CC (Discharge Constant Current), set Current at 20 amps, Voltage cutoff at 2.5v.Step 3: Set Mode as C-CV, Current at 20 amps, Voltage at 3.2v, Cutoff at 0.2 amps.After setting the parameters, select 'OK'. Connect your battery to the alligator clips and click 'Start'. Monitor the testing process through the graphical representation of amps and voltage on the chart. The tester will charge, discharge, and recharge the battery according to the set parameters. The capacity will be displayed in amp hours and watt hours.Note: The wires included with the tester are rated for up to 30 amps. It is advisable to limit the testing current to 30 amps for extended periods to prevent overheating and potential damage to the unit.<blockquote>[[ aff type=aff ~ link=`https://batteryhookup.com/discount/CS5?redirect=/products/zketech-ebc-a40l-capacity-tester-0-5v-40a-charge-discharge` ~ title=`Battery Cell Capacity Tester` ~ image=https://admin.cellsaviors.com/storage/ battery-capacity-tester-5v.webp ~ description=`Great for testing large-capacity single battery cells. Use our link to save 5% now! ` ~ height=small ~ buttonText=`Check Price`&nbsp; ]]</blockquote><h2>Best Battery Capacity Testers For Up To 30V:&nbsp;</h2>The ZKETech EBC-A20 Capacity Tester is highly praised for its reliability and versatility, allowing full control via a computer connection. It's capable of charging, discharging, and recharging batteries to test their capacity. The tester works with a range of voltages and currents for charging (0-19 volts, 0-5 amps) and discharging (0-30 volts, 0-20 amps), making it suitable for a variety of battery types, including 24v batteries (requiring a separate charger for charging).<blockquote>[[ aff type=aff ~ link=`https://batteryhookup.com/discount/CS5?redirect=/products/zketech-ebc-a20-capacity-tester-30v-5a-charge-20a-discharge` ~ title=`Battery Cell Capacity Tester` ~ image=https://admin.cellsaviors.com/storage/30v-battery-capacity-tester.webp ~ description=`Great for testing large-capacity battery packs and cells with a max voltage of 30V. Use our link to save 5% now!` ~ height=small ~ buttonText=`Check Price`&nbsp; ]]</blockquote>Software and Setup: To utilize the tester, users must first download the necessary driver and software, with a specific process for Windows computers in S-Mode. Connection to a computer is achieved through a USB adapter, where users can then access the software to set up and program test parameters. The software's user-friendly interface allows for easy programming of various test steps, catering to different battery types and requirements.Testing Process: Here is an example of <a href="https://cellsaviors.com/blog/steps-battery-testing">how the battery testing process works</a> for a 12v LiFePo4 battery. The tester performs a full charge up to 14.6v, a discharge down to 10v, and a recharge to 12.8v. The entire process is monitored and controlled via the software, with the ability to customize test parameters as needed.Results and Applications: The tester not only displays the battery capacity post-test but also provides a detailed charge and discharge curve, which is crucial for understanding battery performance. The software allows for saving test parameters and customizing the curve title. The unit is also suitable for single-cell testing all the way up to testing batteries in an 8s configuration. However, it is noted that the software is not compatible with Mac computers.Overall, the tester is a highly effective and user-friendly tool for in-depth battery testing, suitable for a range of applications and battery chemistries. Specs: Power Supply:<ul><li>DC 19V-20V, 3.5A or above</li></ul>Voltage Setting Range:<ul><li>0.00-30.00V, stepper 0.01V</li><li>Maximum voltage in charge mode: 18V</li></ul>Current Setting Range:<ul><li>Discharging: 0.10 to 20A in steps of 0.01A (automatic adjustment if power exceeds limits)</li><li>Charging: 0.10-5.00A, stepper 0.01A (maximum current depends on power supply current)</li></ul>Testing Modes:<ul><li>DSC-CC (Constant Current Discharge): For battery capacity testing, discharge current remains constant.</li><li>DSC-CP (Constant Power Discharge): Ideal for simulating constant power equipment, discharge power remains constant.</li><li>CHG-CV (Constant Voltage Charge): Suitable for lithium and lead-acid batteries, charge voltage remains constant.</li></ul>Auto Mode:<ul><li>Supports charge-discharge-charge auto circle tests, recommended for capacity testing.</li></ul>Accuracy:<ul><li>Voltage: Between 0-4.5V, accuracy is 0.003V, ± 0.5%; Between 4.5-30V, accuracy is 0.01V, ±0.5%.</li><li>Current: 0.10-20.00A, accuracy is 0.01A, ± 0.5%.</li><li>Capacity: &lt; 10Ah, accuracy is 0.001AH; 10-100Ah, accuracy is 0.01Ah; &gt;100Ah, accuracy is 0.1Ah.</li></ul>Display:<ul><li>LCD shows voltage, current, time, capacity, energy, etc.</li></ul>Computer Connection:<ul><li>Can be connected to a computer through a designated USB adapter but is not compatible with Macs :(.</li></ul><blockquote>[[ aff type=aff ~ link=https://batteryhookup.com/discount/CS5?redirect=/products/zketech-ebc-a20-capacity-tester-30v-5a-charge-20a-discharge ~ title=`Battery Cell Capacity Tester` ~ image=https://admin.cellsaviors.com/storage/30v-battery-capacity-tester.webp ~ description=`Great for testing large-capacity battery packs and cells with a max voltage of 30V. Use our link to save 5% now!` ~ height=small ~ buttonText=`Check Price`&nbsp; ]]</blockquote><h2>Best Battery Capacity Testers for Higher Voltages&nbsp;</h2>The Eyes.sys Electronic Load Tester is a versatile battery capacity tester, it can handle a wide voltage range from 2-200V.&nbsp; It is on the lower end of the price range offering an affordable option for battery testing.<blockquote>[[ aff type=aff ~ link=https://amzn.to/3NOc1Ye ~ title=`Battery Capacity Tester` ~ image=https://admin.cellsaviors.com/storage/180w-battery-capacity-tester.jpg ~ description=`Great for testing large-capacity battery packs and cells with a max voltage of 200V. This is also the lowest-cost capacity tester that we recommend. ` ~ height=small ~ buttonText=`Check Price`&nbsp; ]]</blockquote>This battery tester features four different operating modes: constant current, constant voltage, constant power, and constant resistance. It also includes an added feature of auto-generating data reports, enhancing its usability. The tester is equipped with Bluetooth functionality, a 2.4” HD color large screen, offering clear and convenient display options for users.For safety and accuracy, the Eyes.sys tester is built with three intelligent safety protections that monitor the discharge status in real time. This feature ensures reliable performance and enhances safety during testing. The inclusion of an external wired NTC thermometer allows for dual temperature measurement, both inside and outside, providing a comprehensive assessment of the battery's condition.Operating Modes:<ul><li>Constant Current</li><li>Constant Voltage</li><li>Constant Power</li><li>Constant Resistance</li><li>Data Report Feature: Auto-generating data reports for enhanced usability</li><li>Display: 2.4” HD color large screen for clear and convenient viewing</li><li>Safety Protections:<ul><li>Three intelligent safety protections</li><li>Real-time discharge status monitoring</li></ul></li><li>Temperature Measurement:<ul><li>External wired NTC thermometer included</li><li>Dual temperature measurement (internal and external)</li></ul></li><li>Additional Features:<ul><li>Tests charging speed and quality of various charging and data cables</li><li>Flexible input wiring interface for DIY connections</li></ul></li><li>Applications: Versatile use in different testing scenarios for batteries and cables</li></ul><blockquote>[[ aff type=aff ~ link=https://amzn.to/3NOc1Ye ~ title=`Battery Capacity Tester` ~ image=https://admin.cellsaviors.com/storage/180w-battery-capacity-tester.jpg ~ description=`Great for testing large-capacity battery packs and cells with a max voltage of 200V. This is also the lowest-cost capacity tester that we recommend. ` ~ height=small ~ buttonText=`Check Price`&nbsp; ]]</blockquote><h3>Conclusion</h3>Battery capacity testers are super important tools that are equally as useful for professionals and hobbyists alike. These testers give you the ability to see what your normal senses simply cannot. They offer a comprehensive insight into the health and performance of batteries, which is critical in a world increasingly dependent on battery technology.The ZKETech EBC-A40L is the best battery capacity tester for low voltages and single cells. The ZKETech EBC-A20 is the best battery capacity tester for batteries that are 30V and under, making it perfect for 12V batteries of just about any chemistry. The Eyes.sys Electronic Load Tester is the best battery capacity tester for higher voltage batteries.&nbsp;Whether you are testing a single cell or <a href="https://cellsaviors.com/blog/building-a-battery-pack-from-18650-cells">DIY battery pack</a>, the right capacity tester can make a significant difference in optimizing battery performance and longevity. With these tools, users can confidently assess and maintain their batteries, ensuring they get the most out of their electronic devices.We hope this article helped you in picking the best battery capacity tester for your needs. Thanks for reading!

Best Battery Pack Capacity Testers

Nominal voltage of a battery pack or cell is an important concept to understand, in this article we cover it in detail. 

Nominal Voltage - What Does It Mean

If you're delving into the world of batteries, you've likely encountered the term "nominal voltage." Don't be intimidated by its technical-sounding name; it's a fundamental concept that's easy to grasp. And besides, the whole reason it exists in the first place is to make things easier to understand.&nbsp;A nominal voltage is basically just the average voltage that the battery will be close to during most of its operation. While the nominal voltage isn't the entire story, it provides enough information to know what devices are compatible with what batteries. So, a 24-volt battery won't always be at 24 volts but a 24-volt inverter does not have to run at exactly 24 volts either. As long as the battery and device you are running have the same nominal voltage, they should work together without issue.In this article, we will elaborate on what a nominal voltage is, how it can be used, why the concept of a normal voltage is important, and go over nominal voltage for common cell chemistries.<h2>What's Nominal Voltage Anyway?</h2>Nominal voltage is basically a convenient compromise. It's a value that represents the middle ground of a battery's operating voltage over its discharge cycle, without having to plot the entire discharge curve. This single figure is much easier for the average consumer to use when comparing battery-operated systems to the batteries that will be used to operate them.&nbsp;An interesting thing to note about battery nominal voltage is that the nominal voltage is the <a href="https://cellsaviors.com/blog/best-battery-storage-voltage">best voltage for storing a battery pack</a> at.&nbsp;<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image&quot;,&quot;height&quot;:468,&quot;url&quot;:&quot;https://lh7-us.googleusercontent.com/LKBjkdj-CmGwyKbqBbi65WnFX17aMDZNBze6Ow34yFRck0HfhigYgUCen4I_fbV0t1El5R7vbYgxwpVOJ7cqwR-f-mqLccVtVXvcMnA2f4gpkrG-A5Kj1i3ArJDOZWMDdnkKs5bRx6b7tYJOy275fKc&quot;,&quot;width&quot;:624}" data-trix-content-type="image" class="attachment attachment--preview"><img src="https://lh7-us.googleusercontent.com/LKBjkdj-CmGwyKbqBbi65WnFX17aMDZNBze6Ow34yFRck0HfhigYgUCen4I_fbV0t1El5R7vbYgxwpVOJ7cqwR-f-mqLccVtVXvcMnA2f4gpkrG-A5Kj1i3ArJDOZWMDdnkKs5bRx6b7tYJOy275fKc" width="624" height="468"><figcaption class="attachment__caption"></figcaption></figure>Basically, it’s just a lot easier to grasp a single voltage rather than a range of voltages. The actual voltage of a battery can fluctuate due to various factors such as its current state of charge, the load it's under, the temperature, and its age. A battery's voltage when fully charged will be higher than its nominal voltage, and as it discharges, the voltage will drop, often dipping well below the nominal value before the battery is considered dead. This fully charged voltage and discharged voltages are the voltage range for instance an <a href="https://cellsaviors.com/blog/min-max-voltage-18650">18650 cell has a min voltage of 2.5 and a max voltage of 4.2</a> assuming its NMC chemistry.&nbsp;For instance, a 12-volt 3s NMC lithium-ion battery's resting voltage when fully charged is 12.6 volts. It will drop too well into the 11-volt range as it's being discharged which makes its nominal pack voltage 10.8V. We still refer to it as a 12-volt battery because when using NMC cells, <a href="https://cellsaviors.com/blog/series-lithium-batteries">3 cells in series</a> is as close as you can get to a 12V lead acid battery voltage range.&nbsp;<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image&quot;,&quot;height&quot;:468,&quot;url&quot;:&quot;https://lh7-us.googleusercontent.com/JiG_hWO1CFcl3WR6Ng53LHVpN5nxcc_7qYXlHLzTj98gEKa9sOjCSkuedlHknxfhxFes4n1yJYsatr8i7EAU4YPsTb9-JfUonglKoW64mLFtfe8icCTHF1Ll-YG6vfqDc5mW3_hT6ixIOQJ85ZfOBpc&quot;,&quot;width&quot;:624}" data-trix-content-type="image" class="attachment attachment--preview"><img src="https://lh7-us.googleusercontent.com/JiG_hWO1CFcl3WR6Ng53LHVpN5nxcc_7qYXlHLzTj98gEKa9sOjCSkuedlHknxfhxFes4n1yJYsatr8i7EAU4YPsTb9-JfUonglKoW64mLFtfe8icCTHF1Ll-YG6vfqDc5mW3_hT6ixIOQJ85ZfOBpc" width="624" height="468"><figcaption class="attachment__caption"></figcaption></figure>While nominal voltage might seem like an annoying oversimplification, it turns out to be a handy little shorthand to understand a battery's operating range without getting bogged down in the details.&nbsp;<h2>Why's Nominal Voltage Important?</h2>Nominal voltage serves as a dependable reference point. It plays a crucial role in determining how batteries are grouped for a particular device, ensuring that the device receives the correct amount of power. Imagine your gadget requires 12 volts to operate. If you know the nominal voltage of your battery, you can easily calculate how many of them you need to <a href="https://cellsaviors.com/blog/series-lithium-batteries">connect in series</a> to achieve that precise voltage level.First of all, the concept of a nominal voltage simplifies the design process of electrical systems. Engineers and technicians can select components that are compatible with the nominal voltage, thus ensuring that each part functions within its intended voltage range. This reduces the risk of overvoltage or undervoltage, which can lead to inefficiency, potential damage, or even safety hazards.Also, a nominal voltage is vital for the standardization of electrical components and appliances. It allows manufacturers to produce batteries, devices, and other electrical components that are universally compatible with standard systems. This standardization is what enables consumers to purchase a battery or device off the shelf and confidently expect it to work with their existing setup.<h3>It's Not Just About One Battery</h3>Remember that when you're using multiple batteries together, such as in a <a href="https://cellsaviors.com/blog/plan-portable-power-pack">DIY portable power station</a> or an electric vehicle, the nominal voltage of the entire battery pack is what matters. This collective voltage depends on the number of batteries you have and how they are connected.&nbsp;For example, if you have 10 NMC lithium-ion cell groups in series, its nominal voltage is going to be 36V.&nbsp;<h2>Why Voltage Varies And Why We Need A Nominal Voltage</h2>Nominal voltage gives us a baseline understanding of a battery's performance under typical conditions. It's like the average temperature of a city over a year – it tells you what to expect, but the actual daily temperature might vary.When <a href="https://cellsaviors.com/battery-pack-designer">designing a battery pack</a>, the nominal voltage is a key factor to consider, especially when the application requires a specific voltage to operate efficiently. The nominal voltage is determined by the voltage of individual cells and how they are connected. For example, if each NMC (Nickel Manganese Cobalt) lithium-ion cell has a nominal voltage of 3.7V, then connecting them in series will sum their voltages. In a scenario where you need a 48V battery pack, you would need to connect 13 cells in series (13 cells x 3.7V per cell = 48V). This is a common setup for light electric vehicles, such as <a href="https://cellsaviors.com/blog/build-ebike-battery">e-bike battery packs</a>, which often operate at a nominal 48V.<figure data-trix-attachment="{&quot;contentType&quot;:&quot;image/jpeg&quot;,&quot;filename&quot;:&quot;example of 48v battery pack nominal voltage.jpg&quot;,&quot;filesize&quot;:80990,&quot;height&quot;:409,&quot;href&quot;:&quot;https://admin.cellsaviors.com/storage/JsD0GCHUemYhaYJX4Ifj6LWJCMK0nXOqMvuJy4l2.jpg&quot;,&quot;url&quot;:&quot;https://admin.cellsaviors.com/storage/JsD0GCHUemYhaYJX4Ifj6LWJCMK0nXOqMvuJy4l2.jpg&quot;,&quot;width&quot;:497}" 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/JsD0GCHUemYhaYJX4Ifj6LWJCMK0nXOqMvuJy4l2.jpg"><img src="https://admin.cellsaviors.com/storage/JsD0GCHUemYhaYJX4Ifj6LWJCMK0nXOqMvuJy4l2.jpg" width="497" height="409"><figcaption class="attachment__caption">example of 48v battery pack nominal voltage.jpg 79.09 KB</figcaption></a></figure>For more demanding applications, such as larger electric vehicles or more robust portable power stations, a higher nominal voltage is often required. To achieve a 72V nominal voltage, you would need to connect 20 NMC lithium-ion cells in series (20 cells x 3.6V per cell = 72V). This higher voltage can provide increased power and efficiency for the system it's designed to run. It's important to note that the battery management system (BMS) is essential in both cases, as it ensures that the battery pack operates within safe parameters, maintaining the longevity and safety of the pack. The BMS will manage the charging and discharging of the cells to prevent overcharging or deep discharging, which can be harmful to the battery's health. Furthermore, the <a href="https://cellsaviors.com/blog/how-bms-balances-battery">BMS will work to keep the battery in balance</a> to help extend the pack's life.Charging and Discharging: During charging, the voltage of a battery increases, often exceeding the nominal voltage. Similarly, when discharging, the voltage drops below this level.Battery Chemistry: Different battery chemistries have different nominal voltages. For example, a standard lead-acid battery typically has a nominal voltage of 2 volts per cell, while a nickel-cadmium (NiCd) cell has a nominal voltage of 1.2 volts.<h2>Real-World Examples of Nominal Voltage in Action</h2>Electric Vehicles (EVs): EVs use large battery packs. Let's say each cell has a nominal voltage of 3.6 volts (common for lithium-ion cells). If an EV requires a 400-volt battery pack, you would need about 112 cells in series (400 volts / 3.6 volts per cell). This series configuration increases the voltage to meet the vehicle's requirements.Portable Power Stations: These often use <a href="https://cellsaviors.com/blog/lifepo4-nmc-chemistry-comparison">lithium-ion (NMC) or lithium-iron phosphate (LiFePO4) batteries</a>. For a power station with a nominal voltage of 24 volts, if using LiFePO4 cells with a nominal voltage of 3.2 volts, you'd need 8 cells in series (24 volts / 3.2 volts per cell). In contrast, using NMC cells requires just 7 cells in series to be considered a 24V battery. This is due to its higher 3.6 volt nominal voltage.Solar Power Storage: In a <a href="https://cellsaviors.com/blog/diy-solar-system">DIY solar power system</a>, <a href="https://cellsaviors.com/blog/connect-solar-panels">batteries store the energy collected by solar panels</a>. If the system is designed for 48 volts, and you're using 12-volt AGM (Absorbent Glass Mat) batteries, you would need four of these batteries in series to achieve the required voltage. In this case, the actual voltage is going to be way higher or way lower than 48 volts because 48 volts is just the normal voltage of this particular system.&nbsp;<h2>Nominal Battery Voltage By Cell Chemistry</h2>Each type of battery chemistry has its own nominal voltage, which is essentially the average voltage a battery maintains during most of its discharge cycle. So, it’s important to consider this when you are working with a given battery.Keep in mind the numbers below are single-cell nominal voltage. So a battery with 13 cells in series would be 13 times the nominal voltage of one cell to give you a pack nominal voltage. &nbsp;<h3>Here is a handy list of nominal voltages for the most common cell chemistries:</h3>NMC (Lithium Nickel Manganese Cobalt Oxide): 3.6 voltsLFP (Lithium Iron Phosphate): 3.2 voltsLead Acid: 2.1 voltsLTO (Lithium Titanate Oxide): 2.4 voltsSodium Ion: 2.1 voltsLiCoO2 (Lithium Cobalt Oxide): 3.7 voltsNiMH (Nickel-Metal Hydride): 1.2 voltsNiCd (Nickel-Cadmium): 1.2 voltsLiMn2O4 (Lithium Manganese Oxide): 4.0 voltsLi-S (Lithium-Sulfur): 2.15 volts<h2>Conclusion</h2>Nominal voltage is more than just a numerical value; it's an important property of an electrical system and understanding it will ensure the efficient and safe operation of battery-powered devices. By understanding the nominal voltage, you can easily know what other systems your battery can safely work with.&nbsp;So, nominal voltage is a fundamental concept that empowers you to make informed decisions about battery configurations. It’s important to remember that the nominal voltage is by no means the entire story.We hope this article told you everything you needed to know about nominal voltages, thanks for reading!

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