(Inset: controller mounted on the heatsink)

Controllers can get pretty hot when they're worked hard or for a long time. For longevity, it's best to mount them on a heat sink.

I scavenged this aluminum sink from a dead 12 volt electronic cooler. It's half of the cooler's Peltier device.

The base of the controller was smeared with thin layer of thermal conductive grease to ensure good heat transfer between the controller and the heat sink.

My experience after taking the controller's temperature (with my hand) many times after driving: it gets warm, but never hot. (Never so warm that it's uncomfortable to touch.)