I've been running VTA using a LiPo for a while, and am finding 1 LiPo more than sufficient! I have a 4200 mah pack and when I recharge between rounds, only about 1000 mah is going back in before it is peaked. In theory I could use that for both qualifiers and the main if I really had to... I don't though as it is only taking about 20 minutes to re-peak. Your mileage will vary running a faster class/motor