Andrew, we have got 2 of those 5Amp (without heatsinks) H-Bridge controllers and have fitted them to 2 of our featherweights. They dont have failsafes, but I dont see why as its only a simple change to the software, I did concider re-programming them but found an easier way, but as it stands you would need failsafes, a PCM type Tx & Rx would do but they are more expensive than the standard ones.

As for the Heatsink, my brother came up with the Idea of using a standard PCs CPU heatsink and cutting it in half and bolting them threw the MOSFETS, these heatsinks are very cheep and on one of them he added a small fan too.

We altered them to work with a 0V-2.5V-5V signal to control the motor speed as they were slightly jumpy with the RC servo signal and the steering reverses going backwards, but so far we are happy with them and will test them out in combat at Sheffield.

One is running on 33.6V with 30V drill motors and the other is running on 19.2V with 12V drill motors, both have a 30Amp fuse on the batteries and has not blown them as of yet.

Current rating is a little difficult to figure out, If you have a 200W motor and your Gear ratio and traction can only deliver 100W before the wheels start spinning then it wont use any more then the rest is wastefull. But if it needs 300W of power to start the wheels spinning then your motor will try and deliver 300W and start to overheat, in time it would burn out if overstressed for too long. So its better to have an overrated motor and not use the power to be on the safe side but at the expense of wasted weight.

The lower the voltage you use the higher current needed for the same power output, also high voltage motors are more effeicnt and as they use less current they also generate less heat.