Understanding and apply of LiFePO4 soc chart

What is soc and how is battery soc measured

soc for batteries stands for “State Of Charge” and this can be described as a measure of the level of energy present within a battery at any particular point in time. This value is usually expressed in percentage with 100% indicating a fully charged battery while 0% indicates a completely depleted battery. This information indicates how long the battery can perform before needing to be charged or completely replaced.

The soc of any battery can be measured in several ways, some of which include the voltage method, the internal impedance method, the specific gravity method, and the coulombs counting method. As stated, the voltage method is the most common as it is the most straightforward and doesn’t require complex equipment or calculations. A high voltage value indicates a full battery while the lowest possible voltage indicates the battery is depleted.

How to check a battery using an LiFePO4 soc chart

With a LiFePO4 battery being one of the highest functioning lithium batteries available, it is possible to determine its charge level using a LiFePO4 soc chart. This chart simply indicates the voltage level of a LiFePO4 battery and its corresponding capacity in percentage.

Therefore, in order to know the charging state of the LiFePO4 battery, you need to use a voltmeter or multimeter to get the current voltage level of the battery and get the corresponding numbers in the LiFePO4 soc chart. For instance, if a 12V LiFePO4 battery displays 13.3V on the voltmeter, you can simply check that it corresponds to 80% on the LiFePO4 soc chart.

What does low state of charge mean

As we’ve established, a state of charge simply indicates the electrical energy levels of a battery with values presented in percentage. So in essence, a low state of charge translates to low energy levels within the battery which would mean a low battery percentage. In dealing with a LiFePO4 battery, a LiFePO4 soc chart would indicate what voltage levels mean a low state of charge for the battery.

What factors will affect the soc of the battery

Where the soc of a battery is involved, there are several factors that affect or determine the energy levels or performance percentage of the battery. Some of these include;
● The application or usage of the battery as this affects how fast or slow energy is being pulled out of the battery.
● Battery chemistry affects the efficiency of the battery itself and how well it performs. For instance,The change of LiFePO4 battery soc will greatly differ from that of a lead-acid battery.
● The temperature of the battery affects the battery’s performance and in turn, the battery’s soc.
● The battery’s maintenance would determine the efficiency of battery chemistry, its temperature, and finally its soc.

How do I know the soc of a LiFePO4 battery

The soc of a LiFePO4 battery can easily be determined using the battery’s voltage alongside a LiFePO4 soc chart for reference. The voltage of the LiFePO4 battery can be known using a voltmeter or multimeter and after that has been determined, you can check the corresponding capacity level of the battery on the LiFePO4 soc chart to determine its soc.

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How do you charge battery according to LiFePO4 soc chart

Charging a LiFePO4 battery is a fairly straightforward activity but a more important aspect of it is knowing the appropriate levels to charge it to. Every battery has a recommended voltage level which it must be charged to reach maximum capacity while maintaining ultimate battery health. The appropriate voltage or percentage levels to which a LiFePO4 battery must be charged can be determined on a LiFePO4 soc chart.

For instance, the LiFePO4 soc chart indicates that an 80% charge for a 12v lithium ion battery is at 13.3V, 26.6V for a 24V battery, and 53.1V for a 48V battery.

Comparison of different batteries soc chart

Different batteries have different soc charts and this is because not all batteries charge and discharge in the same way. For instance, a LiFePO4 battery has a much smaller discharge range between voltage levels and this can be seen in the LiFePO4 soc chart.

For instance, a 12V Lithium battery has its 100% soc at 14.6 or 16.8v. Meanwhile, for a 12V lead-acid battery the 100% soc is at 13.4V and a NiMh battery has its 100% soc at 14.4V. The voltage level between each battery’s soc differs.

What is the difference between soc and DOD

soc simply signifies “State of Charge” and tells the energy levels of the battery. On the other hand, DOD or “Depth of Discharge” is It refers to the percentage of the current actual capacity to the theoretical capacity, which is a completely different concept from soc. The size of the DOD depends on the number of cycles of the battery. For example, if a LiFePO4 battery is used for 4000 cycles, the DOD still has 80% of its actual capacity, and compared with other batteries, the working voltage of LiFePO4 battery is more stable.

What will be the battery voltage when its soc is 100%

The voltage of a battery when it has a soc of 100 differs across a wide range of battery types and voltage sizes as well. For a 12V LiFePO4 battery, a 100% soc will be between 14.6V on the LiFePO4 soc chart. The actual voltage is different according to the lithium ion battery manufacturers, and the parameters of the battery produced may be slightly different.