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Comment by rootusrootus | Hacker News Reader

It still boggles my mind how much power a modern electric motor gets from such a small package. I'm so used to big engines weighing hundreds of pounds making maybe a couple hundred horsepower. Now we have electric motors making quite a lot more (and not to mention insane torque) that I could easily pick up with my hands.

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There are motors with peak efficiency about 90%. The first one of those I ran into was fifteen years ago. Which means not only is it possible but the patents will have expired, if not now then soon.

Power density has gone almost too far. There’s one pancake motor I’ve seen recently where the shape of the enclosure is dictated by mounting concerns. You have to be able to mount the motor to something it can’t tear apart. If they shrunk that motor another 20% then it would be half housing. I’m not sure where you go from there. Thinner? Motor per wheel?

Motor per wheel sounds interesting. As I understand it’s not ideal for handling because of unsprung weight. Maybe that will change? Would be very excited about the prospect of converting cars to purv (somehow)

Motor per wheel doesn’t have to be in the wheel. Could be through a very compact axle, maybe with a fixed gear box to get the angle right.

What would be wild (and probably wildly impractical) is an inductive coupling between the motor (inboard, unsprung) and the wheel.

What if the shock absorber piston shaft were actually an axle?

Huh I know nothing about cars. How would the angle affect the gear box? Isn’t that just for getting the right torque ratio?

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