The Next discussion would be Fusing and E-stops.
From Dimension Engineering:
We prefer that you fuse the motors rather than the battery leads, or if for safety reasons you need to fuse the battery that you do it at a much higher current than the motors. The reason is this:
Because Sabertooth is a regenerative driver, it relies on having a battery to put regenerated energy back into when you command a stop (and at other times). If you draw enough power to blow a battery fuse, all of a sudden the Sabertooth has nowhere to put the energy. It will see the fault, though, and try to stop the motor. It doesn't, however, have anywhere to put the energy (the mechanical energy of the vehicle and the electrical energy carried in the windings and the caps). So blowing a battery fuse will sometimes kill the driver -- which we would replace under warranty, but it's still annoying for all parties.
The better way to do it is to fuse the motor leads. If a motor fuse blows, the motor will freewheel, the Sabertooth will sit there contentedly, and the only thing you will have to replace is the fuse. A very large fuse (100 amps) on the battery lead will protect the wiring in the event of a battery lead short or motor driver failure.
This appears to handle fusing unless there are any other opinions.
So killing the power to the Sabertooth is a bad thing but the motor circuit could be broken giving me a simple but expensive option of a dual 60 amp switch or relay if this practice will not bruise the controller.
Being as I will probably be using Packetized mode Any other E-Stop will be generated by software. This is bad practice in the industrial world and could be bad on a large rover.