# High Voltage Altlernators



## ElectriCar (Jun 15, 2008)

I'm wanting to have an alternator rewound to product 130V or so. If I could get my hands on one it would be very easy to do regen. The AC could be converted to about 180VDC for my 144V pack. I'm in dire need of a cheap regen as I live in a hilly area.

Not only would the regen recapture some of the forward inertia but it would also drastically reduce the power consumption of the vacuum pump as I wouldn't need to use so much brake.

Anyone know someone who could do something with an automotive alternator like that or where I could get a 120VAC alternator?


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## ElectriCar (Jun 15, 2008)

Don't know why I didn't think of this before but why couldn't we use a large alternator like a 200A unit and run it through a 2 or 3kw inverter. Most inverters are rated for a higher peak for a short time so a 2kw unit should be ok.

It might be a 10% or so loss in the conversion but that's irrelevant really. Just wonder how much energy that would help me recover on a coasting slowing to a stop.

Most of my driving is city and in hilly terrain.


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## alicia21 (Feb 19, 2009)

ElectriCar said:


> I'm wanting to have an alternator rewound to product 130V or so. If I could get my hands on one it would be very easy to do regen. The AC could be converted to about 180VDC for my 144V pack. I'm in dire need of a cheap regen as I live in a hilly area.
> 
> Not only would the regen recapture some of the forward inertia but it would also drastically reduce the power consumption of the vacuum pump as I wouldn't need to use so much brake.
> 
> Anyone know someone who could do something with an automotive alternator like that or where I could get a 120VAC alternator?


great tips. I enjoyed reading this


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## ElectriCar (Jun 15, 2008)

Does anyone have any input about using this huge alternator to feed an inverter connected to the charger? I just wonder if the charger can handle being energized so much. ??? Also my Zivan NG5 takes maybe 2-3 seconds to begin outputting to the pack.

Chargers aren't cheap so I'm hesitant to try such. It would be an easy do though with the most challenging part being mounting the alternator. Maybe not challenging so much as time consuming.


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## ElectriCar (Jun 15, 2008)

Anyone know where to get a 120V alternator? Not a generator from Northern tool as it must have constant RPM.


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## Harold in CR (Sep 8, 2008)

Check yer Pm's.


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## Coyote X (Feb 22, 2009)

http://www.scribd.com/doc/487913/Alternator-Secrets

It is easy to make an alternator output pretty much any voltage you want


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## ElectriCar (Jun 15, 2008)

Coyote, I understand how alternators work for the most part, I just don't know how to rework one to make 120V instead of 13-14V. I think the number of turns determines the voltage.

120VAC is a good voltage for charging a 144V pack. When rectified and connected to a bridge rectifier (badboy charger) you'll get a lot more than 120V. Remember that 120V is RMS voltage. The DC potential near 170V. The formula is 1.414 X RMS voltage. Though you won't see that when connected to your pack unless it's fully charged. The voltage will creep up with a badboy as the pack charges as it will with an alternator - rectifier rig.

Thanks for the link though I'd much rather pay someone who knows what they are doing instead of FUBAR'ing one myself only to have to buy another core!


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## Coyote X (Feb 22, 2009)

The link shows how to modify the voltage regulator to make it output whatever you want. It just starts out with the theory and stuff at the start.

I will probably modify the alternator on my car to output 12V or 72V so I can charge my battery pack if the need arises.


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## Harold in CR (Sep 8, 2008)

Question. If you have an Alternator, rated at 100 Amps-12Vdc, that's 1200 watts. IF you change the voltage, doesn't the amp output go down, to maintain that 1200 watt rating ??? Seems that a 200 Amp-12V Alternator is a LOT larger frame, to accomodate the larger windings to get the larger output ???


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## ElectriCar (Jun 15, 2008)

You ever rewind one? I just contacted my motor rewind company and they're going to get back to me about it. Wasn't sure anyone knew enough to do it. If they can't do it I may tackle it if I decide to proceed.

I really want to have some sort of regen and my routes typically are a steady stream of dips and hills. I actually started taking measurements with the GPS yesterday and from what I saw I travel anywhere from 3 tenths to 3/4 mile between major hills while the road elevation typically varies 50-100'. During those trips between the larger dips and hills, the elevation also varies maybe 5-20' for smaller dips & hills along the way.


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## Coyote X (Feb 22, 2009)

Harold in CR said:


> Question. If you have an Alternator, rated at 100 Amps-12Vdc, that's 1200 watts. IF you change the voltage, doesn't the amp output go down, to maintain that 1200 watt rating ??? Seems that a 200 Amp-12V Alternator is a LOT larger frame, to accomodate the larger windings to get the larger output ???


100 amps at 12Vdc alternator could be modified with a new regulator to put out 100 amps at 120Vdc but it would take a lot more horsepower to turn it and the belt probably won't be strong enough so it would need a chain or gear drive. I have always used a rough estimate of 1hp = [email protected] = 300W. [email protected]=4hp, [email protected]=40hp. The bearings probably won't be happy taking that much horsepower but with a gear drive they might not have that much stress on them. There is no chance a belt would handle that though.


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## DIYguy (Sep 18, 2008)

40 HP is no problem for belt drive. You just have to select the correct belt(s)/sheaves or pulleys for the application. Belts are used for several hundred horsepower applications.


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## Voltswagen (Nov 13, 2008)

ElectriCar
You may be able to find one in a scrap yard. My brother was an EMT years ago (1970's) and I think I recall him telling me that their Ambulances were equipped with 120v Alternators to run their equiptment.
Check on that.
Roy


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## Roy Von Rogers (Mar 21, 2009)

Take a look at this....

http://www.windbluepower.com/Permanent_Magnet_Alternator_Wind_Blue_Low_Wind_p/dc-540.htm

Roy


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## ElectriCar (Jun 15, 2008)

Thanks for posting the link. This is exciting as I haven't found anything like it yet. Just have to make it work only when coasting and ideally find one with an electrical field so the output can be switched on and off and limited to a desired voltage, depending on ones pack. 

What would happen with this thing making 350V at 2500rpm? I wonder if the pack would absorb all the voltage thus limiting the output to just above the pack voltage like a charger.

Thanks for posting the link!


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## Roy Von Rogers (Mar 21, 2009)

ElectriCar said:


> Thanks for posting the link. This is exciting as I haven't found anything like it yet. Just have to make it work only when coasting and ideally find one with an electrical field so the output can be switched on and off and limited to a desired voltage, depending on ones pack.
> 
> What would happen with this thing making 350V at 2500rpm? I wonder if the pack would absorb all the voltage thus limiting the output to just above the pack voltage like a charger.
> 
> Thanks for posting the link!


I considered how one would control regen on such an alternator. I'm aware that one can do this electronicly or via relays, but the first thing that came to mind was an electric clutch, like the one used in an automotive a/c compressor. But not sure which would be the larger load on the storage system.

Roy


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