Battery Life
 

How long should a 220SCH 1.2V 2200mAh NiMH battery last in a TM AK 47 while playing?

1.2V...?


Unless that is a typo, that battery won't even turn over the mechbox.

thats per cell and there are 7 cells it is a large battery.

8.4v large. If the AK is stock that battery will easily last all day.

usually... 1mah = 1bb on a normal-ish gerbox....

Depends on other things too. Is it a stock TM or does it have a different spring?

it is a stock TM AK. I went out and bought a backup battery just in case.

The math goes something like this in a perfect world. You will never get the same results from the math in practice.

Amp hours / amps drawn (or max amps dischargable) * 60 = total continuous runtime in minutes

To calculate rounds

Total Continuous runtime in minutes * 60 (seconds) * BPS = Total rounds in battery

That number is going to be very optimistic for a couple reasons. First when your motor starts up it draws considerably more current than that (see here), and conversely when your let off the trigger all that accumulated inertia in the system is lost. Also you can't actually use all of your battery's capacity before you drop the voltage too low for the Motor to turn over or in the case of a LiPo reach the cut off.