ORIGINAL: CGRetired
I have a pair of 1200mah NiMH packs in this plane. I operate them in parallel, each having its own switch and going to a separate channel on the RX. I also use Voltwatch on the Venus II.
I think using two batteries in parallel is very cheap insurance and a very good idea. I have the exact same set-up on my planes. On my 40-size I have a pair of 750 mAh NiMH packs and the Voltwatch. I have never managed to run them down. I would guess they would easily last for 3 or 4 hours of flying, maybe much more.
The extra switch, extra battery, and Voltwatch should only cost about $40