No power under load

Hey guys, I’m having an issue with one of the 30q packs I have. It’s running through a bms. I charged it to 100%. Then checked the cell groups voltages, they show increasing multiples of 4, as I think they should. Plug it in, motors spin up fine. But try riding it, and I get 0 torque, not even enough to keep moving after a push. I swapped for another identical pack I have from same manufacturer, everything runs fine. So I opened up the non working pack, I see no visible defects, how do I trouble shoot from here? I suspect it’s the bms. Should I try bypassing it as step one? What’s step two?

1 Post vesc settings

2 check solder joints

3 what are you using to turn your board on?

The board works fine with an alternate identical battery, so the vesc is not suspect and been configured and working for over a year. The bms has a built in power switch and temperature sensor. The welds and sodder points inside the battery look intact.