Open Loop -different batteries different SOC

So I moved to an open loop setup with my Sol-ark 12k's. I figure there will be some period for the batteries to equalize. However, I am not sure if there is a problem or that I don't know what is suppose to be happening.

I have 1 Fortress 18.5 and 3 EG4 Powerpro batteries. All 2/0 wiring is the same length from the busbar and all connections are tight.

The inverter and the batteries agree for the most part on the voltage within 1/10h of a volt as you can see in the pictures. However, the Fortress state of charge (79.7%) is significantly lower than the EG4's which are all around 86% at the same voltage.

Sol-ark made a change yesterday morning, so should I give this a week to normalize or look at it as a problem i need to fix?

6% difference in estimated SOC isn’t significant.

Heck, it’s probably a rarity that they’re that close..

I’ve been open loop with my 12 k for two years, and for the first year and a half the SolArk was great at estimating SOC. Then it started being really bad, but it’s not a supported feature.

Voltage control (for your time of use settings) works great.

One battery at 80% and the other at 86% is not "significant" at that voltage which is below the knee.
They need to be charged to 54.8V minimum and let them float until they are 100% and the current drops off to below 1A.

..

BentleyJ said:

One battery at 80% and the other at 86% is not "significant" at that voltage which is below the knee.
They need to be charged to 54.8V minimum and let them float until they are 100% and the current drops off to below 1A.

Click to expand...

I guess I thought this was more significant than it was.

BentlyJ, do you mean I should sacrifice some time and first charge them to 54.8 one morning and then let them float charge all day up to 100%? How long do you feel I should allow for that to happen? Would this happen in a day?

The balancing function on the BMS needs time to work and even out the cells. That's why its usually better to use low charging currents so the absorption time is long enough at each cycle to effectively keep the cells balanced. That said, LFP shouldn't be float charged continuously as was common with lead acid.

According to the pics, charging current is 14.1A & 9.3A. When it drops off to 1 Amp on each battery, let them float for an hour. The SoC should be reading 95%+ by then.