Lithium Iron Phosphate (LiFePO4) is a safe and durable type of lithium-ion battery. The battery helps to power many electric vehicles and solar electric systems.
The voltage on your LiFePO4 is the amount of electrical energy the battery can provide. The voltage level also decides whether your battery will work with some devices. As a result, we will discuss LiFePO4 battery voltage levels. We'll also see how to check and increase your battery's capacity.
Voltage Chart for the Different LifePO4 Battery Configurations
The voltage on your LifePO4 battery reduces as the charge level goes from 100% to 0%. So you can estimate the charge level from the voltage. We have added the voltage chart below as a guide. Understanding this chart can help you know the health of your battery.
|
State of Charge (SOC) |
3.2V (Single Cell) |
12V Configuration |
24V Configuration |
48V Configuration |
|
100% |
3.65V |
14.6V |
29.2V |
58.4V |
|
90% |
3.55V |
14.2V |
28.4V |
56.8V |
|
80% |
3.45V |
13.8V |
27.6V |
55.2V |
|
70% |
3.35V |
13.4V |
26.8V |
53.6V |
|
60% |
3.25V |
13.0V |
26.0V |
52.0V |
|
50% |
3.15V |
12.6V |
25.2V |
50.4V |
|
40% |
3.05V |
12.2V |
24.4V |
48.8V |
|
30% |
2.95V |
11.8V |
23.6V |
47.2V |
|
20% |
2.85V |
11.4V |
22.8V |
45.6V |
|
10% |
2.75V |
11.0V |
22.0V |
44.0V |
|
0% |
2.50V |
10.0V |
20.0V |
40.0V |
LiFePO4 Battery Charging Parameters
Correctly charging your LiFePO4 battery will improve its performance. These batteries do well in controlled voltage and current levels. For example, they store more energy and last longer. Applying the correct charging parameters will help maintain the health of your LiFePO4 battery.
LiFePO4 Battery Charging Parameters: Float, Bulk, and Equalize Voltages
LiFePO4 batteries have different needs for bulk, float, and equal voltage. For example, the bulk stage quickly charges the battery at a fixed current until a set voltage. The float voltage maintains charge to extend battery life and efficiency. The equalization helps to balance cells and ensure even charge.
|
Types |
3.2V (Single Cell) |
12V |
24V |
48V |
|
Bulk |
3.4V |
14.6V |
29.2V |
58.4V |
|
Float |
3.6V |
13.5V |
27.0V |
54.0V |
|
Equalize |
3.8V |
14.6V |
29.2V |
58.4V |
Pro Tips for Checking Charge and Discharge Rates
Tracking the charge and discharge rates can help you check your battery's health and performance. To check the charge rate, measure the current flowing into the battery during the charging process. To calculate the discharge rate, measure the current leaving the battery during use. Keep an eye on abnormal rates to ensure smooth battery operation.
LiFePO4 Battery Charging Parameters for Different Voltages
Your battery's charging parameters can vary depending on the specific battery model. Manufacturers provide a detailed charging guide for the different batteries. Refer to the product specifications to prevent damage.
State of Charge (SOC) and How to Measure It
The stage of charge (SOC) measures the available energy in a battery at any time. This quantity is expressed as a percentage.
How To Measure the State of Charge
There are different ways to check the battery’s state of charge. These ways include:
Voltage: Checking your battery's voltage is a simple way to verify the state of charge. But, this method can be inaccurate. This is because cell materials and temperature can affect the voltage. Still, you can get a more accurate reading by resting the battery for at least 4 hours before measurement. Some manufacturers recommend a 24-hour rest.
Specific Gravity: With this method, you will need a hydrometer to measure the SOC. It works by checking the liquid density based on buoyancy. This means you are tracking any change in the weight of the battery’s active chemicals while discharged. For example, one of these chemicals is sulfuric acid. This electrolyte reduces when you use the battery. As a result, the battery’s specific gravity reduces alongside.
Counting Coulombs: This works by measuring the current flowing in and out of the battery. Ampere-second (As) is the unit of measurement for charging and discharging rate.
How to Check and Increase LiFePO4 Battery Capacity
Your battery's capacity will impact its performance and durability. There are several ways to check this capacity. Here’s how to do it:
With a Multimeter: A multimeter checks the voltage of a LiFePO4 battery. You can infer the battery's capacity through the voltage. Set the multimeter to measure voltage. Then, connect it to the battery terminals. A reading near the battery’s nominal voltage shows good capacity. However, very low readings may indicate a bad or discharged battery.
With a Battery Monitor: A battery monitor can give you information about your battery’s capacity. They track parameters such as voltage, current, and energy discharged. It then calculates the remaining battery capacity. The latest models can estimate the battery’s health and lifespan based on your use.
With a Solar Charge Controller: Solar panel systems have a solar charge controller and a built-in battery monitor. These controllers help to regulate the charging process. Also, they show the battery's voltage and capacity.
App Monitoring and Control: Some battery models have an app to monitor capacity. You simply need an internet connection to monitor your battery from anywhere.
Tips for Increasing the Lifespan and Capacity of LiFePO4 Batteries
Some good practices will help you increase the lifespan and capacity of LiFePO4 batteries. Here are some tips for maintaining battery health:
Avoid Extreme Temperatures: LiFePO4 batteries perform best under moderate temperatures. Avoid exposing them to very hot or cold weather. This simple practice will preserve the capacity and lifespan.
Optimize Charging Parameters: Follow the manufacturer's charging voltages and current recommendations. Avoid overcharging your battery. Also, use a suitable charger for LiFePO4 batteries to ensure accurate charging.
Control Depth of Discharge (DoD): Lower discharges contribute to a longer lifespan. Avoid discharging the battery fully. Otherwise, this will stress the battery cells.
Store Batteries Properly: Store your idle LiFePO4 batteries in a cool and dry place. If storing for long periods, maintain a state of charge around 40-60%.
Avoid Overloading: Stay within the specified current limits during discharge or charge. Overloading the battery can cause overheating and damage.
Charge Cycle and Discharge Rates
Your battery's charge cycle and discharge rates are key information. This data determines the battery's lifespan and performance. A charge cycle charges a battery from 0% to 100%, then discharges it back to 0%. LiFePO4 batteries have a high number of charge cycles compared to other batteries. These cells can exceed 2000 cycles.
Depth of Discharge (DoD) and Why It's Important
Depth of Discharge (DoD) is about the discharged capacity of the battery compared to its overall capacity. This value measures how often a battery is used. A higher DoD results in a shorter lifespan.
It's good practice to avoid discharging the battery completely. Or this will wear down the battery’s cells. Manufacturers often recommend a maximum DOD value. This measure improves battery life and performance.
Conclusion
Knowing your LiFePO4 battery voltage, charging parameters, State of Charge, and Depth of Discharge will help you get the best from your battery. We have also shared tips for increasing your battery's capacity.
You can read other helpful LifePO4 battery tips from the Goldenmate Energy blog. Also, you can order high-quality LifePO4 batteries from our online store.
