diy solar

diy solar

3 x 4s batteries need charging question answered


Retired Traveler with a yen for solar and LIFEPO4
Dec 10, 2020

I am down to the last items with a long awaited battery bank. I have now 3 fully configured 4S batteries (280 AH each). :eek:

Putting them in parallel, using 0 GA wire to connect them.

(I was going for 4 batteries, but one has Gremlins, and also space in limited.) :alien: :cry:

So , i will have about 840 AH total capacity. What I want to know is correct wiring for a charger across the whole pack. In other words one charger of say 60A used for charging all cells. Please respond with issues, concerns or suggestions. :unsure:

P.S. I did look this topic up, so if there is a thread about this please be gentle and point me to it! :rolleyes:
The 60A charging current will split 3 ways (20A each battery) if they are at equal SOC. I have a similar set up (a 280Ah with 2-277Ah). Mine are wired with equal length wire to a common bus rather than battery to battery jumper. I see some imbalance, the 280Ah seems to hog charge/discharge with smaller loads, so it may discharge 10A but when I lift the load it will get a bump charge from the others. The battery voltages will track together, the current will shift a little between batteries. With you having 3 batteries of the same age/capacity they should track pretty close.