Cell deviation under load

[Ucatchmydrift]

Hi, finished top balancing 8 x 280ah eve grade a cells earlier.
Now rigged up in series at 24v. Connected to the inverter and pulling about 55a/1400w to test it all.

I have a jk bms all setup correctly as far as i know.

Is a cell deviation of about 0.020- 0.030mv normal whilst under load?
(after top balancing to 3.65v, the cell deviation was 0.001mv) - so pretty good at a guess.

Under about 100amp/2200w load its 0.060 - 0.100mv.. Seems alot, but im a newb, so not sure?

Thanks... ?

 

[Ucatchmydrift]

Left a nut off one of the busbars lol ???

Now deviation is about 0.020 - 0.030 under load of 1.4kw
And about 0.045 under load of 2.2kw..

Sound acceptable?

Thanks ?

 

[100 Proof]

If you were pulling that kind of a load without one cell contributing, it is probably at a higher state of charge than the rest. You might want to rebalance the pack, or at least take that one cell and bring it down to parity with the rest of them.

 

[Ucatchmydrift]

If you were pulling that kind of a load without one cell contributing, it is probably at a higher state of charge than the rest. You might want to rebalance the pack, or at least take that one cell and bring it down to parity with the rest of them.

Yes i was thinking that, but each cell has two nuts on each terminal, which will have helped.. Do you think the deviation figures are ok?

 

[Pierre]

Your cells delta is quite acceptable. Will get better as pack gets exercised.

 

[Ucatchmydrift]

For example:
and the inverter! :

 

[Ucatchmydrift]

Your cells delta is quite acceptable. Will get better as pack gets exercised.

Ok thanks thats good to know ?