I had a cheap 2200 15c 4s battery actually catch fire in flight in one of my EP gliders after about a 30 second burst of power at launch. Fried the ESC and crashed the glider. The battery was ejected at impact, made a flying streak in the sky, and left a 1' burn spot on the grass. The glider has repaired and is flying well. I still use canopy that got burned and show it to the newer electric flyers what can happen when a battery catches fire.