FoxESS Community - Owners & Installers Forum

Hi,

We've just had a couple of EP11 installed and I'm trying to understand how to treat them well. It seems one of the key factors is charging them too quickly, and there is a figure C which you can use to measure this. C seems to be the current which will fully drain the battery in one hour.

As Watts = Volts x Amps, Amps = Watts / Volts, which for the EP11 (10360 watts, nominal voltage 384V) gives

Amps = 10360 / 384
therefore
C = 27Amps

This is the figure given for capacity in Ah on the attached (scrappy) photo of the EP11 EU 2023/1542 document. But in this document they call it 0.2C.
It seems we want to target something close to 0.2C as the charging current to prolong life, but shouldn't 0.2 C be 27 x 0.2 = 5.4Amps?

Hey,

I don't believe you've got the C rating correct, more info as to how to work it out here:https://www.power-sonic.com/blog/what-i ... -c-rating/

But I can save you the reading, on the EP11 battery, they recommend 13 amps DC charge/discharge or less.

Depending on your situation, you might want to lower it to 10amps as long as it doesn't prevent you fully charging in a cheap overnight window or limit your solar charging.