milliamp draw based on lipo size/type/c/mah

[fdproductions]

was wondering if anyone has seen a ecalc type of tool or formula for mAh draw based on Lipo by the minute. Basically something strange is going on inside my z15 wiring so I've elected to rebalanced gimbal and run an independent transmitter with a small baby sized 3s 35c 850 mAh lipo, but I'm looking for a tool to gauge how much air time I can get out of the set up. so far it seems to be running pretty flawless, not running any components on the top plate of gimbal, running a much lighter lens than the 12mm to compensate for the added weight of the gh4, lipo, transmitter...:02.47-tranquillity:

here are the links to my components I'm running:

http://www.tmart.com/Boscam-TX58-80...aign=product&gclid=CIjQg8fbgsACFQINaQod4yAAOg

http://www.ebay.com/itm/like/390866722741?lpid=82

TIA