Understanding WCP Drive Train Calculator

[Chris is me]

Originally Posted by Oblarg

One major flaw of the WCP drive calculator that you should take note of: the "max pushing force" and "max current draw" calculations both use static wheel COF instead of dynamic. This is very misleading, as if you're actually traction-limited, you'll be spinning the wheels and the static COF only matters for a moment until the wheels slip. So, if you're trying to see if your current draw in a pushing match is sustainable without tripping a breaker, the numbers they give are not correct.

This isn't quite as black and white as you make it out to be.

Three cases to consider:
1. Less than your maximum pushing force is required to displace whatever you are pushing. In this case, your wheels don't slip, they start moving before that happens.
2. More than your maximum pushing force is required. You're already not pushing them, whatever. In fact once you start to slip you'll draw slightly less current than the max!
3. Right on the borderline. Behavior varies around here; the winner of the pushing match if head to head is usually who carried more momentum into the push.

The bigger deal that isn't modeled is the effects of voltage drop under load on pushing force and current draw. This is significant.

I think it's plenty reasonable to model at static CoF - unless you have a low gear that's mega low and you're pushing boulders (grippy boulders, made of rock, not foam), your wheels probably won't slip before you move anyway.