amps and charge times on parallel first strings

[jtvt]

Hi

I was wondering if there was any consensus on max charging amps for a parallel first string such as a 4p16s of 280ah 3.2? Max current on an individual cell is 1c which would imply 4c for 4 parallel cells. Realistically that's into arc welding territory, but I'm thinking about additional solar arrays in order to reduce time to charge. Any real world experience? Any one using a high amp BMS?

EVE specs say standard charge time is 2 hr is 0.5c. IIRC, you normally size arrays with FLA so that the array can charge the FLA al least in 1 typical day and ideally in half a day. Maybe there should not be any expectation of charging a 4p16s in a day. Other than the published charge times, I have no sense of charge times on LFP. Is 0.25c rate 3 hrs?


thx

 

[snoobler]

Welcome to the forum.

0.25C is about 4 hours (you're providing 25% of the battery's capacity in an hour)
0.1C is about 10 hours (you're providing 10% of the battery's capacity in an hour)
0.05C is about 20 hours (you're providing 5% of the battery's capacity in an hour)

That's how "C" works. C is the Ah capacity of the cell/battery/whatever RELATIVE to the voltage.

A 4P16S comprised of 280Ah 3.2V cells is a 4*280 = 1,120Ah 12.8V battery.

Its C rate is 1120A
112A would charge it in 10 hours.