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05-20-2008, 12:41 PM
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#1
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Registered Member
Join Date: May 2008
Posts: 9
Country: United States
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Electric Power Car NO BATTERY NEEDED!!
I have an idea to build an electric power vehicle that runs off of a portable generator. I will be driving 60 miles per day round trip to/from work. My thoughts are to use a mini truck so the gen can be mounted in the rear. The mini truck can be lightened up considerable by removing the rear bed among many other things. I am thinking of using some sort of AC electric motor probably a 220 volt? And mount it to the transmission to hopefully get more speed for highway. I have a 5500 watt gen that has a 220 output. I am wondering if the 5500 watt gen would be enough to power an electric motor large enough to run a car @ 60 mph down the highway? Does anyone have any knowlegde if this will work and how big of a gen I will need?
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05-20-2008, 12:49 PM
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#2
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Join Date: May 2008
Posts: 26
Country: United States
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Sounds really inefficient, but good luck to you.
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05-20-2008, 02:36 PM
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#3
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Registered Member
Join Date: Oct 2007
Posts: 68
Country: United States
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5500 watts is about 7.4 horsepower assuming no losses. I'm not sure how much power you need, but you don't have it.
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05-20-2008, 03:32 PM
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#4
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Join Date: Jan 2006
Posts: 2,444
Country: United States
Location: Tiverton, RI
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If you want to run any kind of safe speed think 55,000 watts at a minimum since the electric motor doesn't develop a lot of Horse Power at low rpms you may need even more power. The generator is not going to operate any more efficiently than a bigger motor in the vehicle already. You are trying to move too much vehicle and that can't be done efficiently unless you make it more efficient at converting gasoline to mechanical energy. Even with a small bank of powerful output Batteries and the generator you still are limited to the gas motor in the generator and the size of the vehicle.
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05-20-2008, 03:43 PM
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#5
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Registered Member
Join Date: Feb 2008
Posts: 1,652
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at 100% efficiency, that would get you to about 55mph in a 1500lb vehicle with a low Cd and RR.
In reality, it's barely gonna be safe in city traffic. 7HP is about what they put in electric motorbikes.
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05-20-2008, 05:36 PM
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#6
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Join Date: Apr 2008
Posts: 6,624
Country: United States
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Burning gasoline to make rotational motion, converting that to electricity, and then converting that electricity back to rotational motion is very lossy. Such a design would not offset the losses by the increased efficiency of being able to run the gas engine at its optimum RPM/load combination.
Electric cars gain effiicency from storing power in batteries and recovering power with regenerative braking. The Prius combines those gains with a specifically-designed gas engine + generator combination, and of course the low drag (aero, RR, etc) design.
You're not going to beat the big budget R&D departments of major manufacturers by throwing a generator on a rusty Mitsubishi Mighty Max. Don't get me wrong, it's not impossible for a grassroots effort to beat big money R&D; it's pretty common, actually. It's just not common in this particular sector, and especially unrealistic the way you described.
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05-20-2008, 06:53 PM
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#7
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Join Date: Nov 2007
Posts: 742
Country: United States
Location: Columbus, IN, USA
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not to mention the cost of implementing a variable speed AC motor reliably as you need here.
I'll tell ya first hand, you can't lighten a mini-truck much (unless it's a newer one with lots of interior) the bed ain't much. 2 average size guys can lift a full-size short-bed pickup bed without much trouble. I'd say 150 lbs tops. a minitruck bed is maybe 120 if even...
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05-21-2008, 06:56 AM
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#8
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Registered Member
Join Date: Mar 2006
Posts: 1,325
Country: United States
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My 1,400 pound electric car draws 4,000 to 6,000 watts while going 35mph down a flat road and 22,000 watts for a few seconds while starting from a dead stop, unless you over size your generator to the point that it uses more gas then you could imagine then you are going to need a decent size battery pack that can handle the possible 40,000+ watt draw you are going to need in a truck to get moving from a dead stop.
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05-23-2008, 12:56 AM
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#9
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Team GasMisers5!
Join Date: Nov 2006
Posts: 440
Country: United States
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There are some instances when running a generator with an electric motor can be more efficient than an ICE.
This would particularly be the case if you are cruising at 50mph in a very aerodynamic car. Most of the fuel will be going to overcome engine resistance. If you had a motor-generator combination, you could get much better economy.
If you were really going to do this, you would need to KEEP the original engine, attach EXTREME (Aerocivic-style) aero mods, also get low rolling resistance tyres, and reduce weight as much as possible.
Acceleration would be carried out using the normal engine, cruising would
be using the electric motor (and you would need an electric start generator).
You should find out the gallons-per-hour for the generator. I once looked into this and found that I would be able to get 80mph using this system, from the GPH of a generator at 50% load and an electric motor.
In reality, I would advise keeping your current car, optimising it with aero mods, better tyres, and driving style changes (the most important bit!). A manual transmission swap can make a huge difference if you have an auto.
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05-31-2008, 11:52 PM
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#10
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Registered Member
Join Date: Oct 2007
Posts: 698
Country: United States
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Sounds like you want to re-invent the Owen Magnetic car... http://en.wikipedia.org/wiki/Owen_Magnetic
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