.

[Christ]

I was not aware of that?... I was under the impression that regen was only truly feasible (with any sort of charge efficiency) using 3 phase AC drive.

[gone-ot]

...with SO-O-O many variables, I'm thinking the only viable comparison is TOTAL efficiency, ie: (nu) = (energy.OUT)/(energy.IN)

...so, electric vehicles will obviously "gain" from their regeneration, which gasoline engines cannot do. However, to coast to the BOTTOM of the hill, you gotta climb to the TOP of the hill first!

[Christ]

The way I understand it, regen is basically a waste if you drive like Darin. Just don't get him brake pads for Christmas... they'll go on the shelf.

[Ryland]

All motors need to have some kind of polarity switching, some of them do this with brushes, some do it by drawing A/C, of course some A/C motors also have brushes that run on a commutator instead of an armature, if I remember correctly a commutator is solid and an armature is segmented.
If I understand it correctly a brush less 3 phase motor is your best choice for effecintcy because of their overlapping windings, their lack of high resistance brushes and their high power to weight ratio.
as far as metal for wire in the windings go, copper is strong, cheap-ish and holds up well, silver would be nice and if you want to wind a motor with sliver wire, go for it.

[Daox]

There are so many variables as everyone has stated here winfield. With AC, you can eliminate the transmission and reduce those losses. It all depends on how it is setup. Any motor out there can be made to generate torque at whatever rpm you want by rewinding it.

Are you looking to build the most efficient EV possible? Is this just an exercise on paper? If its the former, sooooo many other variables come into play like rolling resistance and aerodynamics. These are infinitely more important than a percent or two of drive system efficiency.

[dcb]

It is hard to rule out the cost difference between the brushed motors (considering surplus and controller simplicity, paul has a controller kit for $200) and BLDC/induction.

[Daox]

The website is right and wrong. In general what they say is true. However, any motor can be modified to operate efficiently at any rpm. If you are going so far as to rewind a motor or adjust the brush timing, you can change how the motor performs. Unless you have a lot of money to put into a motor, you won't be doing any of this. If you do have the money, thats very cool! Keep reading and learning.

[Daox]

Yeah, that is very far out of my realm of knowledge. I know things can be done, I don't know how to do them though.

The person I'd recommend would be Jim Husted. His website is Hi-Torque Electric. He knows quite a bit about modifying motors, at least DC motors.

[Allch Chcar]

Originally Posted by Winfield1990

So why did you say with AC you could run it without a transmission since DC you could do the same

3 phase AC = no multi-geared transmission.
That alone makes the efficiency favor AC.
Most AC motors are designed with a flatter torque curve
whereas DC motors tend to peak really low then fizzle.
I've seen cheap AC namely the golf kart series motors with peaky efficiency too. And all AC motor graphs I've seen lose a lot of efficiency once they start to pass 5k RPM.
Brushless DC can do regen too but I've yet to seen one over 30kw.
As for drag racing, I've seen more favoritism towards DC. Most production cars in the works are going with AC and Sports cars just use larger AC motors. So if you wonder which is better for daily drivers, an AC motor with 1 speed transmission would get the most range. Finding one affordable for the DIY is possible, the monster Golf Cart motors should be big enough for a compact. If you're going to build one, good luck with that .

[Clev]

Originally Posted by Allch Chcar

3 phase AC = no multi-geared transmission.
That alone makes the efficiency favor AC.
Most AC motors are designed with a flatter torque curve
whereas DC motors tend to peak really low then fizzle.

Plus, most production AC EV motors are good to 15,000 RPM. The Advanced DC is good to about 5,500-6,000 RPM. Longer power curve means less need for a transmission.