I run both LiIon and A123 batteries. So far, no issues with the LiIon. However I did manage to burn out 5 Hitec servos using freshly charged unregulated A123 packs(2 Hitec 5645s and 3 Hitec 5955s). These were 2s2p (30c) 4600mah, A123 Racing batteries. Lucky for me the plane (1/4 scale Corsair) never left the ground.