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So I'm fairly new to all this EV stuff and as I wait patiently for my Bolt to arrive, I've been reading up on solar and wind power for the home. While researching wind power, I see many wind turbines using things like permanent magnet generators to produce the power off the wind as the turbine turns. So this got me thinking - why aren't there any permanent magnet generators (or similar) built into all 4 wheels of EV's? Regenerative braking works to recharge the batter as the car is slowed down, but on wind turbines, just the rotation of the blades produces the power.

Colour me curious.....
 

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I was trying to come up with an elegant response to this, but basically the reason why is the conservation of energy. It requires energy to turn the wheels or the blades in the case of the wind turbine. Adding a generator into the wheels would require more energy to turn the wheels (the additional energy required would be more than the amount of energy being returned by the generator).
 

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I like to think with products like cars its all a chess game, they want to do enough but not too much. There's planning that happens years well ahead of a models release so you bet Chevy already has things scheduled for specific years as long as competition evolves as they projected.
 

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So I'm fairly new to all this EV stuff and as I wait patiently for my Bolt to arrive, I've been reading up on solar and wind power for the home. While researching wind power, I see many wind turbines using things like permanent magnet generators to produce the power off the wind as the turbine turns. So this got me thinking - why aren't there any permanent magnet generators (or similar) built into all 4 wheels of EV's? Regenerative braking works to recharge the batter as the car is slowed down, but on wind turbines, just the rotation of the blades produces the power.

Colour me curious.....
Are you implying that perpetual motion is possible?

Turbines in the wheels would work no better than mounting a windmill on the roof. Either of those are going to produce drag, and it will cost more battery power to keep the car moving than is recaptured.

Plus, adding unsprung weight is generally not a good thing. In wheel motors have are rarely used for that very reason.
 

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Because having a separate generator on each wheel would not product any more power than having a motor connected to two wheels, like the Bolt.
The energy generated from braking is related to the amount of slowing of the vehicle, and spreading that over four generators would not make any more juice than two or even one.
 

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On a different note, I'm surprised that vehicle manufacturers haven't yet begun using in wheel motors instead of axle motors. Although this would increase the unsprung weight of each wheel, if the vehicle isn't a sports car, I'm not sure it would make much difference on handling while greatly increasing packaging efficiency as well as allowing for all wheel drive.
 

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On a different note, I'm surprised that vehicle manufacturers haven't yet begun using in wheel motors instead of axle motors. Although this would increase the unsprung weight of each wheel, if the vehicle isn't a sports car, I'm not sure it would make much difference on handling while greatly increasing packaging efficiency as well as allowing for all wheel drive.
In addition to the unsprung weight issue, it's a cost issue. One motor with a simple gearbox/differential is likely a lot cheaper than four motors. There is also the safety factor. What happens when the controller malfunctions and applies asymmetrical thrust to the wheels?
 

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On a different note, I'm surprised that vehicle manufacturers haven't yet begun using in wheel motors instead of axle motors. Although this would increase the unsprung weight of each wheel, if the vehicle isn't a sports car, I'm not sure it would make much difference on handling while greatly increasing packaging efficiency as well as allowing for all wheel drive.
The design and maintenance issues with having the motors exposed to the elements inside the wheels of an automobile would make the motors very expensive to build. Plus the drive motor does provide regenerative braking quite effectively.
 
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