After 2 years and 22 thousand miles, I finally decided to add a chill plate to my controller and use water cooling. This makes the controller run much cooler. :-) I had been using a large heat sink with a fan to cool the controller but there were times when the controller got up to 70C. I used a small radiator with fan used on computers to cool the controller and it works great. You don't need an automotive grade radiator to water cool your controller. We'll see how things work out in the summer months.