I have an issue with a victron 150ah LiFePO4 (600ah bank of 4 at 12v) not balancing after several attempts. It balances after about 6 hours on hook-up via the multiplus 3000/12/120 but as soon as we boat off it won't balance the next time I charge via engine or geni/multiplus, and BMS shuts down due to one cell (always the same one) going OV at 3.76v
The guy (pro) who fitted the system (now unwell) thinks its a duff battery and has asked that I swap 1 and 4 over to see what happens (cell 4 in battery 1 is the issue)
Now having a look my black BMS cables aren't wired like anything I've seen.
All diagrams I can see the left black cable of Battery1 goes to the left BMS port; the right black cable or B1 goes to B2 left cable; B2 right to B3 left, B3 right goes to battery 4 left and lastly battery 4 right to BMS right port (a 4 battery version of this link https://www.victronenergy.com/blog/2019/07/11/new-veconfigure-manual-new-detailed-marine-schematics-and-dvcc-explained/)
Mine goes B4L-B2R; B4R-B3L; B3R-B1L; B2L-BMSL; B1R-BMSR
I can't find anything wired vaguely similar ANYWHERE. The only possible reason I can see why it was done this way is that my left hand black cable is too short to go to the BMS left port and needs the 2m victron (https://www.victronenergy.com/accessories/m8-circular-connector-male-female-3-pole-cable-2m) extension cable
Q1) is my wiring enough to mess with the cell balancing?
Q2) should I buy the extension cable and wire it as per the diagrams I can find regardless of whether I have a duff battery on not?