How to controllers fail?

[MMMM]

My question is: how do controllers fail? Do they only fail because of heat build up? I can fix that with a fan. If we make the truck do lots of wheeles and brake it a lot, will this cause a power spike and burn something up? It seems to me that if these things only fail because of burning up, a good fan could prevent this.

[RC-Monster Mike]

Generally, voltage/amperage spikes are controller killers. Usually, failures don't happen from heat buildup (controllers are thermally protected), but from wiring issues or bad connections. A long set of wires connected to a lot of cells is a recipe for controller death. I have had Schultze controllers go before I even had the car on the ground and they blamed the motor connectors (BS if you ask me). Keep the wires short and make sure the solder joints are quality. This as well as selecting the right controller for the job will lead to a long controller life. A fan never hurts (I always run fans on my controllers).