I've been trying to get my heavy running again now that exams are all over, having wired up the drive I've found that the motors keep cutting out. I'm using a Vantec RDFR47E Speed Controller, one bosch 400 on each side, 10:1 gear ratio, 10" go-cart wheels and a 12v SLA battery.
It happens on the bench if I push it quickly to full forwards or reverse and also when the robot is on the ground if I don't bring up the power very very slowly and even then it cuts out when I reach about half speed.

Anyone got any idea what's going on?
I thought it could be current limiting but I can't believe my setup is drawing 70A continuous, 220A start-up.
Is it possible that the battery voltage is dropping bellow 9v (the minimum voltage for tr esc)?