I apologise for jumping into an old thread. I am also building a robot using a Roboteq AX2550 and 2 Magmotors (S28-400) for the drive. I was worried by the problems that Ceros had had. Could you tell me how you finally resolved the issue? I wondered whether the answer might be to reduce the maximum current per channel to 60 amps, or put fuses in the motors feeds - perhaps at 80 amps or perhaps 120 amps to protect both the controller and the motors. The Roboteq manual talks about 'flyback', caused by the motor impedance which means that the current to the motor can be significantly higher than the current from the battery. How do other roboteers get around this problem?