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gwbas1cyesterday at 2:24 PM3 repliesview on HN

It's easy to forget that most of the weight in an electric car is the battery. It's ICE cars where a lot of the weight is in the motor.

That being said, could this be adapted so that a 2.8lb motor produces 100 hp? That would allow putting a small motor in each wheel, thus completely eliminating axels, driveshafts, and allow recapturing the space they used to occupy. It also wouldn't significantly impact unsprung weight.


Replies

eightysixfouryesterday at 5:23 PM

First, no, it won't scale like that.

Second, don't forget that you're trading one complexity for another. Eliminate a drive shaft and you still have to get power to the wheel somehow, which means now you're running high power electrical cable in a very dynamic environment with exposure to the elements. On top of that, you need to cool the electric motor, so you're probably running some kind of fluid out to it. Not that it isn't a solvable problem, but it probably doesn't reduce the weight much, if at all, when the system is all added up. You'll find that while you eliminate an axle, you still need to mechanically connect the two wheels together (look at the rear subframe on an FWD car) for strength, which also reduces the weight loss. Then the steering on the front... etc.

Until a more significant change than this motor (where maybe a 2.8lb motor could produce 100hp without needing active cooling), we're better off with "inboard" motors still.

neuroelectronyesterday at 2:45 PM

Is it really easy to forget?

show 2 replies
pfdietzyesterday at 9:22 PM

So, this could be better in hybrid cars?