When I plug this in to charge my iPad 2, it functions for about 5 minutes. Then it starts to cycle off and on. The longer it runs, the faster the cycling becomes. When the iPad gets above 80% charge, it stops cycling. I suspect the current draw from an iPad is too great and the unit heats up, causing some protective device to shut it off until it cools down. Then it comes back on. If I take it out, it is quite warm.