Is Regen being activated while coasting on low gear setups?

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LEVer   10 kW

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Is Regen being activated while coasting on low gear setups?

Post by LEVer » Apr 24 2016 4:17pm

If you have a geared setup that is 4:1 or lower (meaning 5:1, 6:1, etc.), is the regenerative braking being activated when you go to neutral especially when travelling at high speeds or going downhill?

Where does all of those amps go that the motor is now generating? I've heard of instances where the ESC will turn on even when disconnected from the battery when riding downhill. Is this where the drag comes from in belt setups, and not really from the belt itself?

EDIT: I suppose I should be more specific. Is Regen being activated "more or sooner" while coasting on "low-er" geared setups? Has anyone done a 1:1 belt-driven setup and experienced any drag?

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Re: Is Regen being activated while coasting on low gear setu

Post by Ptown_Cruiser » Apr 24 2016 7:38pm

As far as I understand it, no. When you backdrive the motor it creates voltage difference between the phase leads, however, (at least in the case where the esc is on and in neutral) the mosfets are switched off, and so there is "infinite" resistance between phases. In the absence of a finite load no current can flow according to V = IR. So, basically a voltage is being generated that corresponds to the speed of the motor, but no current is actually flowing.

As far as the esc turning on when you back drive the motor I have definitely seen this happen, and it is related to this phenomenon somehow (the voltage potential that is created), but I don't really know how. At this point you are back driving the mosfet, and the gate of the mosfet is probably (maybe?) floating. I think it all gets a little squiffy here...

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Re: Is Regen being activated while coasting on low gear setu

Post by LEVer » Apr 24 2016 11:15pm

That's a really good explanation on why the ESC's turning on when going downhill even when they are not plugged in to the battery. I'd still like to know why a 4:1 gear-ratio has less coasting ability than a 2:1 gear-ratio. Is it the belt, is it mechanical or electrical? Why do the magnets feel like they are "grabby" when the motor spins more while coasting? Should they "not" grab when turned on, in neutral and not producing anything? You'd think that the bigger wheel pulley will easily overpower the smaller motor pulley and just keep them spinning, but this is not the case.

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