Drive Train Calcs - Not trusting my results

[Chris is me]

Originally Posted by Nemo

It is highly dependent on several factors. Let's say I assume the following:
CoF = 1.2
Drive efficiency = 0.80
Carpet-wheel efficiency = 0.93
Enough resistance to cause voltage to drop to 7.8 V / 6.7 V for 4/6 CIM drive
Charged battery voltage = 12.8 V

4 CIM is traction limited at about 11 ft/s
6 CIM is traction limited at about 14 ft/s

Change any of the conditions I listed, and you get an appreciable change. I encourage you to download the spreadsheet and start messing with the numbers along the left side.

It is really important to note that these calculations are for traction limited at *stall*, not at 40 amps or max power. If you're trying to gear for traction-limited pushing, you definitely want to gear slower than this.

For Carl's data above - note that 20 uses KoP wheels in their drive. Your mileage will vary with higher and lower traction wheels, and even different wheel diameters!