Increasing discharge current for a SuperPack

DIY
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1

Hello

We have a yacht and recent battery problems. Its a 12v system with 2 x SuperPack 12v/200ah batteries in parallel. If the max. continuous discharge per battery is 70A and peak is 100A (10s) then, when set-up in parallel, shouldn’t discharges double - ie continuous 140a and max 200A (10s)?

We’re having other (possibly unrelated) issues whereby our Balmer MC-614 regulator is not telling the Balmer alternator to kick in (for fully-charged superpack batteries) when we have a large current discharge (ie when anchoring or using electric winches) so without that 100A (or so) charging current from the alternator, our superpack batteries are shutting down when the anchor winch draws more then 80/90A for a few seconds.

The batteries are connected ‘diagonally’ (see 3. Battery bank wiring) to a (+) busbar. I’m wondering whether the batteries (+) should each be separately wired to the (+) busbar to double the internal BMS discharge allowance? We’ve had two marine electricians who haven’t been able to help.

Thanks for your help.

2

The specs of the battery are terrible. Maybe you could parallel with a 16V 500F Maxwell Supercapacitor or a high-current Lithium starter battery like a NOCO Lithium NLP30 700A. I have had a parallel battery bank only draw from one battery before, but that did not bother me because the one doing work had the largest BMS. I believe it might have something to do with pressure from one battery stopping the discharge MOSFET from closing after they are fully charged. The other parallel batteries to contribute after a while, but not immediately.

See if you are pulling current from both with a clamp meter.