FM boobytrapped your board! STOCK BATTERY CONNECTIONS ARE REVERSED! A reminder and explanation. Do not connect a stock XR battery to anything other than a stock BMS without understanding polarity.
Current flows in a direction and you will always see a positive and negative (black & red) wire for power. XT30,XT60 & XT90 connectors are commonly used in electronics and have a proper way of being installed. The pointed end should be negative (black) and the square end is positive (red). Many manufactures of these connectors will even label them with a - & +
A history lesson and one of FM’s shadiest moves:
The Plus had no repair blocks and the world was good. The Plus battery was small and external battery mods were on the rage. The XR was released with better range and with it we started seeing the anti-consumer side of Future Motion. They installed the XT60 from the battery to the BMS reversed. Why? I will let you make your own conclusion.
VESC builders are doing the right thing by keeping XT60s as they should. This means you need to buy or make a XT60 adapter to disarm FM’s booby trap. Thanks FM!
Side note: we are all learning, but if you are building a VESC, you should understand the concept of polarity and know how to check it with a multimeter. This is electronics 101 and you can get basic multimeters cheap on Amazon