Noah,

I'm definitely no math expert, but from what I can see, your calculations look OK in the sense that they show the batteries relative power output per cell versus relative weight.

I don't think wattage is the term you want to be using though which is probably what's throwing people off.
I'm not completely sure but I don't think you can get a batteries output in wattage without an active load since wattage, as was stated, is a measure of power consumption, not capacity.

The reason i'm not completely sure is that, and this is something that just now occurred to me, technically the 2200 mAh rating assumes a 1 milliamp load to begin with since that's how the capacity ratings are derived, so maybe you can assume a nominal watt output without a physical load just for theory purposes as you have done to gauge relative battery power.

Basically, your original calculation may prove correct, in a round-a-bout sort of way, at least on paper. In the real world it wouldn't apply since you wouldn't be obtaining wattage from the battery end, as the load would be coming from the motor, not the battery.

I don't know the proper answer to this question. Perhaps some one more well versed in electric and battery theory will be able to chime in.

As for the rest of your post, most controllers that ship with these helis are only built for 3 cells, if you've got one capable of 16 volts, then you're golden in that you don't need a new controller. Less expense on your part .

As for motors, my own personal experience in both using and selling brushless motors has been that load current is far more important than voltage, and most motors will work much higher than their mfg. rated voltage, but won't work much higher than their rated loaded amperage.

That said, the big difference between a motor designed for 3 cells versus 4 cells is in mechanical design and general efficiency. On 4 cells, the motor will be spinning quicker, which means the bearings not only need to be rated for a faster speed, but things like the magnets need more attention to ensure they don't dislodge during flight from increased centrifugal force. Cooling is also important since the higher RPM means more overall friction and thus heat buildup. motors designed for higher voltage usually yield more power at that voltage setting too since they're more efficient in that RPM range.

Most motors can be pushed passed their rated voltage without much trouble in my experience. How long they last, though, will vary wildly on manufacturing quality. Even from the same company, some motors are built better than others. Some can be pushed way out of range and operate flawlessly for their lifespan, others will fail after a few flights or simply refuse to work.

Case in point, i've got a motor here that i've been using in plane conversions that was originally rated for only 4 cells. I'm running 6 cells through it (22V), power output is excellent, motor stays only warm to the touch after a flight. No failure so far . Have had to replace the bearings once already though.


Anyways, for your setup, keeping track of headspeed would be the easiest way to do this. Shoot for 2500 - 2800 rpm. You will naturally get a lower draw current using the 14 volt battery versus 11 volt as long as you keep the headspeed within reasonable levels. Lowering the draw will result in prolonged flight time, which means you've got an efficient system.