I am currently running a 6s system in a 550 size helicopter. The batteries that i have been using are 2x Hitronex 3s 4100 mAh 11.1V 3s1p 50c. I seem to keep cooking these batteries, i try to land at about 70% discharge, let them cool and charge again. however after only a few flights one of the two packs gets hot and expands at this point i am binning the battery and replacing with new. I am now at that point again of needing to replace the batteries and thought that a change of battery is the way to go. I noticed that flight Test use Turnigy batteries. I have been looking at the Turnigy nano-tech 5000mah 3S 35~70C Lipo Pack, These seem to be the about the same price as the other batteries that i have been using but what are they like? are they reliable? Flight Test: Why do you use them? Any in put would be great thanks.