I had my inline power meter out today and tried out a few full-power readings.
First off, my non-airsoft.
Stryker high-speed plane - 250Watts
Typhoon aerobatic plane - 150Watts
Now, on to airsoft.
ICS MP5 on full auto.
7.2V 3300MaH Sub C battery - 72 Watts @ approx 10 amps
8.4V 3700MaH Sub C battery - 96 Watts @ approx 11 amps
9.6V 1700MaH RIS battery - 92 Watts @ approx 9.5 amps
What I found very interesting was that the 7 cell battery outperformed the 8 cell battery. I knew it was possible - I just wasn't expecting it.
Using these figures, I could fire full-auto on the 7.2V battery for 20 minutes solid.
I tried again on my ICS M16 and got the same result. My CA M4 wasn't too much different, so I quit comparing. Robert Goulet's are 10Watts.
Food for thought.
(I use an Eflite power meter that shows Volts, Amps, and Watts. I have it setup with inline Dean's connectors. This handy device gives me instant readings for my R/C stuff so I can make easy tweaks powered on.