When reading the battery specifications, you may have noticed that the charge and discharge current of the LiFePO4 battery cell is indicated by “C”.

What is C rating?
A C rating is a rating of how quickly a battery can release energy. This rating is combined with the capacity of the battery to determine the maximum discharge.

This is very important when you are considering battery selection for your solar electric system. Especially if you have some high power heating type appliances, they tend to pull a lot of current from the battery side the moment they are turned on.

How do you calculate the C rating?
Let’s take the EVE 3.2V 280Ah LFP battery cell as an example.


In the specification, the charge/discharge current is 1C and the maximum charge/discharge current pulse is 2C (3s).

So,
Continuous charge/discharge current = 280Ah x 1C = 280A.

Maximum charge/discharge pulse current = 280Ah x 2C = 560A.