Finally took the plunge into Lipo batteries for my AEG, for the past year I have been using a add on bag strapped to the stock with a 3700mAh large Nimh battery powering my gun. This gets quite heavy after a while and was a bit overkill!
I got two Vapex 7.4v 1300mAh 20C stick batteries, they fit perfectly in the stock tube and still allow me to slide it nearly all the way down. The plan was to swap them over at lunchtime so could get a days use out of them but in fact after checking the voltage it was quite obvious that one would last all day
The only downside to Lipo’s is the way they have to be charged and maintained. A specialist charger is required to balance the charge to both the cells to ensure the best performance. It is also advisable to charge the batteries in a fireproof bag as they have been known to swell up and burst into flames, but this only really happens if you abuse the basic rules of charging them
Manny Villalba 