I connected it to another 12v battery via jumper cables, and let it sit for about 10 seconds. I then hooked the battery charger up and it charged. So I needed to trick the BMS with the other battery, i guess.

I would assume the BMS would keep it from 100% discharge, no? battery chargers wouldn’t recognize it, so I hooked it with jumper cables to another 12v battery and let it sit for a couple minutes, That woke up the BMS and it charged up again.