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electric/hybrid plug-in


Guest AlK

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Guest AlK

O.K. I admit I am no rhodes scholar, however I have been perplexed about 1 aspect of the electric/hybrid vehicles. We all hear about severe short ranges on electric vehicles, and then you have to recharge it. Now when I was a child I of course had a bicycle. On that bike I had a search light and that light was run by a little electric generator that had a friction wheel that rode against the front wheel of the bike. So as you rode in the evening or at night the little generator would produce electicity to make the light shine. Since there are 4 wheels on an electric/hybrid vehicle, why can't they put some sort of generator on the vehicle to recharge the batterys as you drive.

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I'm dumb to even say this Al, but what the heck.

Somewhere in my pitiful learning years, someone explained that there is always a loss of energy when producing or regenerating energy. Evidently, to generate enough electricity to recharge your batteries would take a very heavy load on your generating device, which would suck more power from your batteries....ummmmmm, or something like that. blush.gifsmile.gif

Now, let's see what the electrical experts have to say about it. wink.gif

Wayne

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">why can't they put some sort of generator on the vehicle to recharge the batterys as you drive. </div></div> Because you cannot create or destroy energy. Whatever energy the generators are producing is being provided by the main propulsion engine/motor. So whatever you put back into that main engine was only what you took out in the first place, less friction and efficiency loss.

You can however recapture some energy by a dynamic braking arrangement where you convert enertia and/or gravity into electricity whenever you decelerate, which is put back into the battery. It helps with the milage but it alone won't keep the batteries charged....Bob

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Guest AlK

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bhigdog</div><div class="ubbcode-body"> <div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">why can't they put some sort of generator on the vehicle to recharge the batterys as you drive. </div></div>

[quote} Whatever energy the generators are producing is being provided by the main propulsion engine/motor. So whatever you put back into that main engine was only what you took out in the first place, less friction and efficiency loss.Bob </div></div>

Bob

not arguing with you because I do not have the knowledge, what I am talking about is a generator on each wheel much like the generator I had on my bike. If 4 wheels are generating energy, that energy is going to the batterys and not the main engine. in an electrical motor the main engine drives the wheels. In my process those wheels drive the generators, the generators generate energy that goes back to the batterys.

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Alk, I remember those generators too. I also remember that you had to pedal a little bit harder when the generator was against the bicycle tire. The added friction on the wheels from the four generators would eat up a little bit more of the motor's energy than they would produce because they are not 100% efficient.

There is still no free lunch, and there is no such thing as a perpetual motion machine.

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What ever energy the generators are producing from the wheels was first provided to the wheels by a gasoline engine or a motor. So if there are generators on the wheels more gasoline must be burned moving the car to make up for what the generators are "stealing". Same thing if it's an electric car. More energy must be taken out of the batteries to drive the generators than the generators can produce. It's kind of like buying dollar bills but paying $1.25 for each one.

The problem is because of friction and inefficiency the generator on the wheel scheme uses more energy than it gives back for a net loss.

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Most of the current hybrids use braking to generate electricity for the very reasons you mentioned. Since generating power puts a load on the 'motor' (remember when carbureted engines dropped about 50-75 RPM when you turned the A/C on) they use the braking action as a good time to run the generator.

By the way, at least one electric car company is working with electric companies to see if their systems could handle a LOT of electric cars being plugged in during the day...on top of everything eles.

Just as electric utilities are paying people rebates to go to upgraded (less usage) appliances and do other things to cut down on the load on the grid, someone seemed to finally notice that plugging in a bunch of cars could be an issue.

Hmmmm......

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Since there are 4 wheels on an electric/hybrid vehicle, why can't they put some sort of generator on the vehicle to recharge the batterys as you drive.

</div></div>

They do. When coasting in drive in a full hybrid (Civic, Insight, Prius, Camry, Fusion/Milan, etc.), the differential directs motion to the generator/motor to charge the battery. (Generally when coasting the engine is off.) This function works even with partial throttle, reversing into a drive mechanism for the wheels when demand dictates. The motor/generator can power the car on it's own, or with the engine. When driving at a steady state (as on an interstate) it's typical for the hybrid system to switch back and forth as needed.

Braking multiplies this same transfer of kinetic energy to the generator/motor (charging the battery MUCH more) in proportion to braking demand.

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Guest EMF-Owner

This is the first stage of braking on my 1912 Rauch & Lang Electric car. When I pull the control handle back past neutral (for lack of a better term) the motor is converted to a generator which slows the car and charges the batteries.

As has been said already, putting generators on all the wheels would be the same as driving with brakes dragging. The motor would have to work much harder using more energy to overcome the braking affect of the generators.

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