Quote:
Originally Posted by BrianG
To determine your average power output:
- Figure your battery capacity in Amp-minutes. Amp-minutes = Ah X 60.
- Measure your runtime (in minutes).
- Divide amp-minutes by runtime. This is your average current draw.
- Multiply the average current draw by the nominal battery voltage (1.2v/cell for NiMH, 3.7v/cell for lipo, and 3.3v/cell for A123 cells).
- Your burst power will be roughly 6x the average power.
This is your average power. However, since cars are "peaky", there will be actual spikes far greater than that and valleys smaller than that, but it at least gives you an idea.
So, let's say you have a 4s setup that gets 20 minutes of runtime on 8Ah batteries.
Amp-minutes = 8Ah X 60 = 480Am.
Average current draw is 480Am / 20min, or 24A.
Average power = 14.4v X 24A = 345.6 watts.
Burst power levels would be somewhere around 2,000w (345.6x X 6). |
Very Nice Brian. I like this.
Seems like there is always going to be alot of variables that are either hard to put a value on, or ones that are hard to figure into the equation.
Wouldn't efficiency have a big impact on this?