After you've been running your electric RC for awhile you have to stop and have a cool down period. Even if you have an extra battery pack charged up and ready to go, you need to give that motor a little rest. That's something my son has trouble comprehending sometimes. As a result, I've had to replace some internal components that got overheated. One of these is the electronic speed controller or ESC. Just like the battery pack and motor, the ESC needs a rest too. My son's Traxxas Stampede has a had a couple of meltdowns that resulted in replacing the electronic speed controller. His ESC has a heat sink designed to draw off heat from the delicate electronics inside but that's not always enough.

Remember, in the long run you'll have a lot more runtime if you include sufficient downtime during playtime (my wife came up with that clever line so blame her if it makes you groan!).