Electronic Gears?

[Thalass]

Hey folks.

It has been pointed out to me that in an ICEmobile your accelerator pedal does not go the whole way in for full speed - you push it down untill the revs get to where you want, then you change gears and pull it out again.

Now for an EV you have only one gear (in an AC conversion, at least), so I was wondering if anybody had trouble maintaining an accurate speed with such a relatively small range of movement?


I was thinking that perhaps you could have a circuit that put a DC bias on the input voltage to the motor controller. So, say 'first gear' has no bias, and full pedal movement gives you 0v to 4v, then 'second gear' gives you 5v to 8v, then 'third gear' gives you 9v to 12v. That way your speed range is stretched over three pedal movements, which ought to make it easier to maintain a set speed - a higher resolution per km/h.


Has anyone had this kind of trouble? Is something like this even needed?

[a4x4kiwi]

I had the same concern. but was going to cross that bridge when I got the EV going. As you suggest, a relay could be switched depending on speed to bias the pot apropriatly. Kind of like my reverse circuit.

A Picaxe micro could do this reasonably easily depending on how the speed sensor is handled.
(see my blog for schematic of reverse circuit)

Cheers, Mal.