When the phone is connected at mhl, battery falls with 30-40% for a move time. Otherwise the real problem is after disconnecting with mhl. Then battery lose 60% in less 1 hour, until phone is turn off, and when i touched it is very hot. But when i restart the phone after use mhl there is not such problem. Im with stock rooted rom, cos CM dosnt support good mhl second screen, even on CM11.