BMS shutdown, reset, new problems....

[ptnick@gmail.com]

I have a hard tail bike with a BBSHD and a MIGHTY MINI 52V battery. I've used it for five months with no problems whatsoever. I love it ! BUT when I took it off the charger yesterday I discovered that the BMS had shut off, likely from plugging the battery into a non-energized charger. (won't do that again). I learned in this forum how to reset the BMS by feeding charge current into the output wires of the battery pack and that was successful.

THEN, when I went to reconnect the fully charged battery pack to my motor there was a large spark and the BMS shut down again. My motor connectors are all XT90's with spark arrestors. I can still
reset the BMS by the same method, but the spark reoccurs, the BMS disconnects, and I seem to be stuck.. Please please help.

All wires are polarity color coded, no short circuits, yet big sparks.

thanks!
Nick

[max_volt]

I understand some bms need to be disconnected from the cells for proper reset. Plus the circuit could be inspected for defect.

[ptnick@gmail.com]

I’ve checked with a voltmeter to see if somehow polarities had changed or if there were an obvious short, and found nothing.
Question: when you check the motor leads for continuity should the circuit be open or continuous? How else might I check the
circuitry? Thanks!

[OhmsLaw]

It looks like the XT-90 has some sort of mechanically switched resistor to provide the spark arrest feature. I’m surprised it is not an MOV but then there would be a huge lollipop sticking out of the connector. Anyway, maybe the switch broke or the resistor blew out.