stableblade,

I'll take some pics tomorrow of the battery in the heli...I have been taping a 1cm thick piece of high-density foam rubber on the end of the pack to keep the it insulated from the motor. This is the battery I have been using...

http://www.hobby-estore.com/11-1v-2200man-battery.html

It is a perfect fit in all dimensions and at 175g it also perfectly balances-out the 36! Because it's a snug fit, you might need to file down the spots inside the frame where it was broken after being molded - otherwise it can gouge the battery! Basically, the battery slides all the way back to where the frame narrows...and the front just touches the stock canopy. The height and width are a perfect fit inside the frame, also.