У вашего броузера проблема в совместимости с HTML5
When upgrading your power wheels battery to something other then the stock, you need to make sure the motors stay cool, and these clip on heat sinks are an easy way to keep them cooler then stock.
Here is where I got them on hobby king. Just make sure you get the MM for the motor you are putting these on, however the 36mm should work fine, but the 40 might even work better.
http://hobbyking.com/hobbyking/store/__38006__Dr_Mad_Thrust_Series_Alloy_Motor_Heat_Sink_for_36mm_size_motor.html