RE: radio upgrade
Like Dave said, NiMh's can false peak. I never fast charged over 1C, and typcally was closer to .5C. Another thing to help detect a false peak is to use a charger with a display that lets you know how much charge went into the pack, rather than one that just has blinking lights, ect. If you typically put in say 500mah when you charge, but it for whatever reason kicks off at 150mah after the same amount of flying time, you know it false peaked.