A Guide to Better Understanding the LifePO4 Battery Voltage Charts

LiFePO4 (Lithium Iron Phosphate) batteries are commonly used these days for various applications. And it is one of the most preferred when it comes to solar panels. That is why familiarity with the battery voltage chart is essential. 

The voltage of LiFePO4 batteries is relatively flat. This  means that it does not really change that much across a wide variety of charge and discharge setups. If you want to learn more about the terms found in a LiFePO4 battery voltage chart, then this article is for you.

Nominal Voltage

For a fully charged LiFePO4 cell, the ‘nominal voltage’ that you find in the chart is the average voltage. LiFePO4 batteries’ nominal voltage is around 3.2 volts per cell. And the battery’s charge and discharge levels can be calculated relative to this nominal voltage. It is vital to closely monitor the LiFePO4 battery performance by considering the nominal voltage.

Charge Voltage

The charge voltage for LiFePO4 batteries is typically 3.6 to 3.8 volts for every cell. This means that you have to charge LiFePO4 batteries within this voltage range. This way you can ensure an effective and safe charging.

Discharge Voltage

The discharge voltage for LiFePO4 batteries is around 2.5 to 3.2 volts per cell. To prevent over-discharging, do not let the battery go below the minimum voltage. Doing so can lead to capacity degradation. It will also reduce the overall lifespan of the battery.

Flat Voltage Curve

LiFePO4 batteries have a flat voltage curve during the cycle which means that it remains constant until it reaches the end of the discharge cycle. This allows for a more stable and consistent power supply. It will provide a steady voltage output for all the connected devices.

State of Charge (SOC)

The LiFePO4 battery voltage chart will give you an estimate of the proper battery charge. You can have an idea of the battery’s state of charge (SOC) by monitoring its voltage and then comparing it to the chart. And for more accurate SOC monitoring, use a BMS that can measure its voltage and other factors.

Temperature-Compensated Voltage

You always have to remember that LiFePO4 battery voltage can be greatly affected by environmental temperature. At colder temperatures, the battery voltage may drop and it may rise in warmer temperatures. It is important that you also take this into consideration when looking at the voltage values provided by the battery manufacturer.

Voltage Drop

The voltage of the LiFePO4 battery starts to drop faster toward the end of its discharge cycle. This means that the battery is close to its fully discharged state. Monitor the battery voltage during discharge. To prevent possible damage, never remove it beyond the recommended minimum voltage.

Understanding the LiFePO4 battery voltage chart can greatly help if you want to closely monitor the battery’s charge. This will also prevent overcharging and over-discharging. As a result, this can extend the battery’s lifespan. However, if you are still not sure how to read the chart, it is best that you consult the battery manufacturer’s specs and instructions.