Help diagnose cut-out please!

[bjm522]

So there's a rail running from battery (-) to a bunch of rectangular components (resistors?) in parallel, then to another rail which runs to controller (-). I'm assuming this is the shunt. I can't see any obvious damage to any component there.

in the second pic, left is charger -, middle is controller, right is battery. I'm sure you're familiar with this BMS.

 

[bjm522]

Directly powering the controller has solved the problem.

I'll keep the BMS in there for charging/balancing and use the CA for lvc function. The BMS shuts off at 2V/cell; should I set the CA to cut out at ~40V to make damn sure none of the cells go under because of a little imbalance?

I'll check the BMS in detail to see if I can solve its problem, and just order another one if I can't find it.

Thanks again soooo much for all your help. It's good to have it back up and running again.

 

[fechter]

If that works, then I would certainly measure the individual cell voltages after a run to make sure one isn't getting destroyed.

You could also bypass just the shunt portion of the BMS and possibly still have cell level LVC protection.

 

[frogblender]

Did you find out what was wrong with your BMS?

I seem to be having a similar problem, but I'm in the early stages of debug.
40A Infineon Controller, with HS3548 rear, 48V10Ahr LiFePO4 (ebay "Sun-Thing28")

 

[bjm522]

Yeah, one of the circuits was bad, likely from a short. The resistance across cell 1 control circuit was a lot lower than the others, when it should have been the same. Replaced BMS and everything works fine.