I’m using custom 2/0 cables about ~5” in length and have been happy so far, but perhaps I’m not looking for the right thing.Don't underestimate this. I've directly observed the difference between cables and busbars. It adversely affected my BMS due to high voltage fluctuations in the cell-level readings, causing inappropriate balancing, SoC auto-adjustments, etc. I abandoned cables in favor of bus bars for these reasons.
Can you describe what measurements would expose the same problems you saw and what test / stress scenarios are most likely to expose those problems?
Reading your post more carefully, seems as though the primary issue is with BMS sense accuracy.
For my use case, I am bottom-balanced and use an active balancer only activated after battery is drained to ~3.125V / cell (25V) and no charge or discharge is occurring.
The battery never charges past 80% and I have no cells getting much past 3.350V (SCC never gets out of bulk/boost).
Since the passive balance of my BMS only kicks-in above 3.55V, I never charge up anywhere close to cell HVD of 3.75V nor discharge anywhere close to cell LVD of 2.1V, the cell sense of my BMS essentially never does anything (which my be why I’ve not seen the issues you ran into).
What was the magnitude of fluctuations you encountered in cell read and at what charge and/or discharge current levels?
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