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You can stop completely with reversed polarity braking, which isn't regenerative. Many fork-style trucks already do this, but it requires a skilled hand. (Foot?)

If you can give the regen phase a field strong enough to counteract the gravity-weight of the vehicle, it would remain still, but you'd have to maintain the field, which would kill your batteries in short order. (Compared to not using it.)

Unfortunately, I'm sure federal DOT requires that all vehicles have a mechanical service brake, and I think several states require a fluid-type brake as well for passenger vehicles in excess of N lbs.

Well, Ernie Rojers taught me a new term called "well to wheels", but the answer is a horribly complicated and incestuous mess.

http://ecomodder.com/forum/showthrea...-evs-8099.html

There are even those that will insist riding a bike is worse than driving for that matter, and the agendas are not very bashful.

Best you can do is pick your fuel and keep beating your high score.

I asked this same question to the EVDL a while back, and the Yodas of the list seemed to feel that system efficiency is in the 75% ballpark for a series DC conversion. That's batteries, controller, DC/DC, motor, contactors, etc.

Controller efficiency tends to be ~97%+ or similar, motor and charger are ~80-90% depending on the specifics . Everything else is variable and depends on driving route. Even if my lighting system draws 300W, at 60mph that's only ~5Wh/mile extra. Otoh, if I'm stuck in heavy traffic at a 5mph crawl, then my lighting system turns into a ~60Wh/mile draw, fairly significant. The same roughly goes for other electric accessories, albeit w/ different parameters.

Talking with the local guys, I believe the ranking would be:

3 phase AC
brushless DC (very close to 3 phase AC)
series wound DC
1 phase AC

Daox -
Is this inclusive of controller/hardware efficiency as well?

I.E. - Lets assume the 3 phase motor is the most efficient, but the 3 phase controller, on average, is only 80% efficient... would that not make the brushless DC motor and controller the clear winner?

I believe that's what Winfield1990 was inferring in the last question. Interested to know myself, as well.

Well, the controller component that sends power to the motor uses the same components for AC or DC (mosfets or IGBTs). So, I don't think it will really matter.

This is really getting specific, and for all intents and purposes I've heard that brushless DC is the same as 3 phase AC. You'll likely never notice a difference in efficiency between the two on the road.

But you gain the ability for regen, should you desire that, with 3 phase.

Thanks for the info!

Well, you could also regen with a permanent magnet DC motor too. :)

FYI you responded fast, I edited my response as I don't think the conversion of DC to AC will have a noticeable effect on efficiency.