RPAT. I am no expert, and have limited experience, but have found a solution that works great for me. First of all, this is what I have tried:
7.2V 350 mAh Battery (nicd) - Could climb once, descended and could't get more that 10 feet off the ground again. Eeks.
7.2V 600 mAh Battery (nicd) - Slightly better performance than above, but flight time of about 5 minutes before she became dangerously unfly-able. The bird stall easily, speed is your friend.
9.6v 720 mAh Batter (nimh) - Good performance, ran at 80% throttle after takeoff due to my concern over high voltage. Plane flew better....but I wasn't totally impressed...
7.2V 2100mAh Thuner Power LiPoly - WOW, great performance. Flies for over 20 minutes before I chicken out and land (ESC set too low, dont want to overdrain pack). I did some measurements and found something weird!!! My current draw is MORE with the LiPoly at 7.2V than my nimh at 9.6V!!! (7.75A MAX)
Sooo, I now love and impress folks with my A10 on LiPoly. I couldn't see myself going back. Combine the huge storage for long flights with lighter weight, and the plane is now happy.
I know this wasn't a cheap solution, but it is what works for me. BTW, my A10 has no wheels and I threw on a relatively heavy coat of paint. I mean honestly, I didn't buy the plane for anything other than looks!!!
Chris