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Reinen

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Because it's also known as regenerative braking.
And interestingly, it's more efficient to climb up a mountain and regenerative brake back down than it is to travel the same distance on flat ground.
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Gee-pah

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I’ve always wondered if you have an electric vehicle and you’re in 2wd on the highway. Why can’t they design those 2 free rolling front (or back) wheels or axles to recharge your battery? If you think of the concept of a generator isn’t it an ice engine turning magnets inside an armature? Why can’t the wheels or momentum of the vehicle do the same thing?
Or make some kind of a 5th rotating small tire below the vehicle with suspension so it can handle bumps. This free turning wheel would be just to produce electric for the vehicle battery?
@DaveNH @Reinen

Hey Steve:

I think Dave answered your question, but in a way that, IMHO, some color commentary might benefit from--no offense to Dave.

While I like your way of thinking, one irrefutable law of physics is that when energy is transferred from one system to another--and I bet you know this--the transfer is never 100%.

Some energy is lost to the environment. Notice I didn't say "destroyed:" as energy is neither created nor destroyed, just transferred or moved.

Given this fact, to add any device to a moving part that might convert, say, rotational energy--such as that of moving wheels--into the electricity of one coil rotating around another (your basic electrical generator) would create frictional forces that would slow that wheel to a point that the energy source to move that wheel (e.g. an ICE engine, or an electric vehicle's battery) would have to provide more power than that gained by the generator attached to the wheel.

Now--in the case of braking, such ideas work great in that they relieve the frictional wear of the brakes and generate power. The problem though is that in maintaining speed or acceleration in a non-road downgrade, such systems would expend more energy than they'd produce.

I hope this helps. :) But know I like the way your brain works!!
 
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Reinen

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@DaveNH @Reinen

Hey Steve:

I think Dave answered your question, but in a way that, IMHO, some color commentary might benefit from--no offense to Dave.

While I like your way of thinking, one irrefutable law of physics is that when energy is transferred from one system to another--and I bet you know this--the transfer is never 100%.

Some energy is lost to the environment. Notice I didn't say "destroyed:" as energy is neither created or destroyed, just transferred or moved.

Given this fact, to add any device to a moving part that might convert, say, rotational energy--such as that of moving wheels--into the electricity of one coil rotating around another (your basic electrical generator) would create frictional forces that would slow that wheel to a point that the energy source to move that wheel (e.g. an CE engine, or an electric vehicle's battery) would have to provide more power than that gained by the generator attached to the wheel.

Now--in the case of braking, such ideas work great in that they relieve the frictional wear of the brakes and generate power. The problem though is that in maintaining speed or acceleration in a non-road downgrade, such systems would expend more energy than they'd produce.

I hope this helps. :) But know I like the way your brain works!!
You're absolutely right, front wheels generating while rear wheels power will only put you behind. The difference lost to friction and heat.

BUT if you drive up a long steep hill then drive back down, regenerating the entire 2nd half, you will regenerate to a point greater than the energy you would have used traveling the same distance on flat ground. Not back to 100% of course, but more than flat ground travel. EVs are surprisingly conducive to mountainous travel.
 

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You're absolutely right, front wheels generating while rear wheels power will only put you behind. The difference lost to friction and heat.

BUT if you drive up a long steep hill then drive back down, regenerating the entire 2nd half, you will regenerate to a point greater than the energy you would have used traveling the same distance on flat ground. Not back to 100% of course, but more than flat ground travel. EVs are surprisingly conducive to mountainous travel.
..and your conserving physical wear and tear on your brakes...a double win!!!
 

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..and your conserving physical wear and tear on your brakes...a double win!!!
And no burning brake pad smell at the bottom of an 8 mile road with a 1 mile elevation change (which I'm all too familiar with). A triple win!
 

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Thanks Andy and Reinen. I guess if it were that easy someone would have done it already. I'll stick to plumbing.
 

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EV's are only the future because manufactures have completely limited our options to only that. Hydrogen cars are a better solution I wish were talked about more.
 

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EV's are only the future because manufactures have completely limited our options to only that. Hydrogen cars are a better solution I wish were talked about more.
Perhaps someday (perhaps not) Hydrogen will be a better fuel than battery based technology, but it just isn't today. From the energy needed to separate hydrogen, to the amount of energy per volume it carries, to its safe containment: it's just not there yet.

Manufacturers are being forced by the EPA to act now, and right now, electric is a more viable alternative.
 

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EV's are only the future because manufactures have completely limited our options to only that. Hydrogen cars are a better solution I wish were talked about more.
Perhaps someday (perhaps not) Hydrogen will be a better fuel than battery based technology, but it just isn't today. From the energy needed to separate hydrogen, to the amount of energy per volume it carries, to its safe containment: it's just not there yet.

Manufacturers are being forced by the EPA to act now, and right now, electric is a more viable alternative.
For the record, “Hydrogen cars“ are still EVs at their core — FCEV, fuel cell electric vehicle. They often even have batteries to store any excess energy created until it’s needed, but of course they’re much smaller than those in BEVs (battery electric vehicles).

There are FCEVs available today, though only a handful. I think part of the reason they’re not more popular is that neither the technology nor the infrastructure is nearly as mature/reliable/tested as existing battery technology and power distribution infrastructure (and I say that while also saying that battery technology has a ways to go, too).

I do think it’s unlikely we will see too many FCEVs in the consumer vehicle space. I personally suspect it will probably shake out like diesel vs gas, with FCEVs filling the same niche as diesel engines and BEVs being the norm In the US.
 
 



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