New motors that are high KV – probably means that if you didn’t change your VESC settings then the previous motor min values are now producing too little breaking torque. Either that, or your BMS tripped and wouldn’t accept the return voltage. Definitely share your Vesc settings.
Were you close to a full charge? Brakes will fail with a smaller battery at or near full capacity. The vesc has no where to dump the extra energy so it jusy wont brake.
Ive had this happen to me on a 10s3p with 97% battery it was quite the scare. I believe someone makes a product now to fix this problem with smaller batteries.
You said your battery could do 20 amps total or per motor? I see you have it set as 30 per motor for a total of 60. What configuration and cells does it use? lipo/liion?
Your “absolute maximum current” is set to only 30A, I would suggest resetting it to the default value which is a bit above 100A if I recall. A sudden current spike from breaking could have easily passed that.
Also, I noticed that you have dual VESCs over canbus (I assume that’s how the Flipsky dual works since it has 2 usb ports). Make sure you have the same motor settings for both, and also this means your battery current limits are too high! Assuming your battery is from Samsung 30Q cells (which are good for 20A per cell), your battery limit should be 20A per VESC, and charging (“battery current max” aka regenerative breaking) limit should be like 10A per VESC. (Which is still 2.5x higher than rated for the cells, but hey you have a small battery and breaking is important, just try to be easy on it to preserve longevity of the battery)
I wonder if it really was the BMS or something that cut off as you were trying to put too much amps into it.