Battery for bicopter

You have two issues to deal with, capacity and maximum amperage rating of the battery. C rating was mentioned above, and that is the relationship between the mah capacity of the battery, and the maximum sustained amperage it can deliver.

A 30C battery with 1200mah capacity would be capable of delivering 1.2 x 30=36 amps for 2 minutes (less the amount you need to leave in the battery to not have it drained fully).

I would start with figuring out your maximum current draw, and do the math for both how long the battery can last at that draw, and whether the amperage drawn is within the C rating of the battery.

I only find some lipo batteries can actually deliver at their C rating without sustaining damage. Some of the cheap ones can't, and become damaged quickly.