Keeping battery bank balanced: Relibatt RE12-100BL

[ADDvanced]

Hey all, I have a fairly simple system in my bus, it's 200watts of solar on the roof, a renogy 40A mppt charger, and two Relibatt 100Ah batteries.

I charged both batteries with a walmart battery charger (set on lithium) and THE CHARGER said both batteries were 95% full, so I topped them both off to 100% (again, charger stated this).

A week later, I installed them in the bus. One of the cool things about these batteries apart from the self heating function, is the built in bluetooth to see what the battery is doing. I installed the app, and one said 65%, the other said 50%. I wired up the 65% battery into my system, and just used that for a night without the second battery, to try to drain it close to where the other one was at.

Once I had both batteries at 50%, I hooked them both up (parallel). The issue is today, after a day of charging one battery is showing 64% and taking 5.7A, and the other battery is showing 56%, and only taking 3.8A.

I guess I'm not sure why they are getting further apart, or why the battery that is further ahead is taking more current. Appreciate any help, this forum is badass and I have learned so much!

 

[sunshine_eggo]

Run them to 14.4V and hold for two hours.

Critical that all battery connections are properly torqued and the main leads are attached across the bank, i.e., (-) terminal on battery 1 and (+) terminal on battery 2. If you connect both main leads to a single battery, that battery will bear the lion's share of the discharge and charge current.

They will also draw different current based on their SoC. IMHO, the batteries are not reporting a calibrated SoC yet.