Drive system jerkiness is all fixed. The problem was the AX3500 and not a Vex compatibility issue. The board had a dry joint on the main power control tab which was causing a short. The speed controller thought the battery was low which cause the fail safes to kick in and turn everything off to avoid damaging the Mosfetts.
I’d gone back and forth on the phone with RoboteQ for a few days, and finally they just overnighted me a new board which fixed the problem instantly. While I was removing the cables to send the old board back the tab connector popped off the board totally.
In the process of troubleshooting the problem, they also convinced me to reconfigure my batteries to have a dedicated 12V supply to the board rather than using a single shared 12V supply for everything. They explained that the symptoms I was seeing were very similar to a low battery problem due to the motors drawing too much current.
I’m probably going to keep the batteries separate for now, but will have to rethink the wiring and my fuse block as I was hoping to just get away with one battery feed which also made charging easier.
The real worrisome thing is he’s way too fast and really dangerous. He can zip around at lightning speeds and can plow through most obstacles because of his weight. I may need to have a fast/slow switch.
He’s also shacking himself to pieces and has already dropped several screws.