BSLBATT battery packs SOCs all over the place.

[Super Fly]

Hello

Can some you all chime in here so I can get your opinions. I am testing 8 X 5KW BSLBATT (Powerline USA version) battery packs. These are all connected in parallel via 2 bussbars.
The issue here is that if they get fully charge, the SOCs of all the batteries will be relatively close between 90-100%.
Once the battery pack starts to get to about 70%, the SOCs start to run all over. Seems some batteries are depleting faster than others. Attached is a perfect example of what is happening.
I supect some of these battery packs do not have grade A cells as the manufacturer said or they are very poor quality.

Give me you opinion guys.

 

[BentleyJ]

The first test should be to verify the actual current on each battery. You will need a clamp on DC ammeter, sometimes referred to as a Hall effect sensor. If it is determined that the batteries are not being discharged at equal currents with a constant load on the whole set, then you need to start looking for high resistance connections. An IR camera may be helpful also.

 

[Super Fly]

The first test should be to verify the actual current on each battery. You will need a clamp on DC ammeter, sometimes referred to as a Hall effect sensor. If it is determined that the batteries are not being discharged at equal currents with a constant load on the whole set, then you need to start looking for high resistance connections. An IR camera may be helpful also.

What I am doing now is a full charge where pack is at 100 SOC and then will monitor it from there.

 

[Super Fly]

all balanced now. lets view 6 hours later.