Don't know what happened. Just finished boarding and about to turn the board off when it started to smoke. Turned it off and still smoking. Was thinking about turning the garden hose on it but changed my mind. Ran into the house to get a screw driver to take the lid off but decided that was not a good option. If I was to take the lid off, I'd be providing oxygen for the fire. I figure I'd let it run its course. No flames but a lot of white smoke. After the smoke stopped, that's when I took the lid off. Seems like one of the batteries went belly up for whatever reason. The burnt up battery pack stayed hot for quite sometime before I could safely touch it. Got to say it was an exciting end to a great ride.