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 Posted: Jan 22, 2012 - 02:22 PM |
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Joined: Feb 06, 2009
Posts: 836
Location: TN
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I have pictures I will post later.
It was a five week project from buying a parts car to driving. All for less than $2K at that time.
I cut the rear mount flange from a junk VW engine. To it I bolted a spacer to connect the electric motor. I used two sprockets and coupled by banding with a double row chain. This was done to get around my less than perfect machine work.
I used a small gear pump to maintain oil on the rear thrust bearing. I mainly used 2nd and 3rd gears of the 4-speed. The car would do 50 mph. Most driving was in town at 30 mph. The flywheel was cut down and the clutch was maintained. Depressing the clutch killed all power to the motor. Releasing the clutch would start the motor, this saved idle losses, mainly the field current that was about 20A.
I replaced the heavy gear oil with automatic transmission fluid since the area had cold winters. The car was significantly lightened. I used a 36 Volt 9 battery supply with an additional battery to run the controller, lights and other needs. I even added a modified JD generator to provide additional distance. That was not successful due to noise and vibration of the single cylinder engine. I could not drive with the distraction. |
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Posted: Jan 22, 2012 - 03:43 PM |
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Joined: Feb 06, 2009
Posts: 836
Location: TN
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Posted: Jan 22, 2012 - 03:56 PM |
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Joined: Dec 11, 2007
Posts: 6856
Location: Cleveland, OH
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Cool project!
I take it they named the "Knight Rider" car after you!
JC |
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Posted: Jan 22, 2012 - 04:49 PM |
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Joined: Feb 06, 2009
Posts: 836
Location: TN
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| No, but the KitCarlson nick name is from building three kit cars, the electric and several vehicle restorations. |
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It all starts with a mental vision.
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Posted: Jan 22, 2012 - 10:20 PM |
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Joined: Dec 15, 2005
Posts: 958
Location: Brazil
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Wwwoowww  , you did it on a really car (fusca, how we call this car in Brazil), really nice...
What was the motor power?
Today we discuss some design of the car... It will be to use on the unpaved streats... |
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Regards,
Brunomusw
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Posted: Jan 22, 2012 - 10:41 PM |
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Joined: Sep 04, 2002
Posts: 21276
Location: Orlando Florida
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| There is one other AVRfreak with his own EV... sgomes. I see sort of a trend in conversions... they tend to be more of the low voltage high current variety. The storebought EVs seem to use 330V DC. They think consumers want 200KW for good acceleration, rather than a puny 20KW for good endurance. I'm a cheapskate. I'd settle for something like a Miata with 3 mph per sec accel... .14 Gs. As long as it cost less per mile to drive than my beat up old Buick that gets 24 mpg on $3.40 per gal gas (14 cents a mile). Seems like .33 KWhr per mile x $0.15 per KW hr is 5 cents per mile. Somewhat better. |
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Posted: Jan 23, 2012 - 12:04 AM |
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Joined: Feb 06, 2009
Posts: 836
Location: TN
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The motor was rated 10HP continuous duty. Peak currents reached 400A, about 20HP. DC motors have huge torque at low RPM.
My technology was old school. If I did it today I might use a 3PH AC motor and variable speed drive. Just connect the batteries to feed the DC supply. Not sure how hard it would be to to get batteries from a Prius or Leaf. With all the safety regulations, it may not be possible to get license plates or insurance.
Even today hybrids and electrics are a novelty, uncertain economics even with federal and state subsidies. |
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It all starts with a mental vision.
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Posted: Jan 23, 2012 - 02:15 AM |
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Joined: Sep 04, 2002
Posts: 21276
Location: Orlando Florida
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| I think I'd try a little mazda pickup as a donor vehicle. I want to put a front bumper to rear bumper contractor rack on it with pv panels. You have a 2 or 3 HP charger during the day. And a little RV diesel genset in the back for a range extender. |
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Posted: Jan 23, 2012 - 03:27 PM |
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Joined: Dec 15, 2005
Posts: 958
Location: Brazil
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Quote:
My technology was old school. If I did it today I might use a 3PH AC motor and variable speed drive. Just connect the batteries to feed the DC supply
Well I thought about Ac motor, but I think is simple to run on dc motor, I mean to run it.. But I will quote the ac motor too..
And to make the dc voltage for the ac motor, I see some problem on it, how to get 110V x 1.414... |
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Brunomusw
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Posted: Jan 23, 2012 - 03:48 PM |
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Joined: May 28, 2006
Posts: 716
Location: Toronto, Canada
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Electric traction uses high voltage, I mean, not 12V in order to avoid high currents.
At 12 V, your solid state switch has at least 1V drop if not 2 or 3V. Multiply this with 50 - 100A and will get the loses on the switch. Plus the wires are bulky.
The automotive starter is not a good idea, it has high brushes friction, and you do not have a convenient access to its shaft. Most of them uses bushing, which are not suitable for many hours to be run. The good part is the modern ones uses planetary gear box which offer a high torque.
One way could be some DC motor, small diameter, long motor, and used at high speed with a toothed belt (like timing belt). High efficiency, quiet, low maintenance.
Another approach would be to have four motors, one per wheel, direct drive. You avoid many problems this way: differential, transmission, small size for the motors.
The project is challenging in many aspects: battery, weight, small space, small diameter for the wheels restrict you to use small and powerful gear / transmission, dust, water, moisture, all the ingredients for an automotive / military project.
And the benefits? An electric bike would be a nicer project.
George.
don't forget to add ABS  |
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Posted: Jan 23, 2012 - 03:52 PM |
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Joined: Feb 06, 2009
Posts: 836
Location: TN
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| I assume you are using batteries. Just place them in series, lots of them. It may worth investigating what the minimum DC supply voltage for the drive. There might be off the shelf e-car controllers by now. Batteries, motor, and controller = $$$$. |
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Posted: Jan 23, 2012 - 10:51 PM |
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Joined: Dec 15, 2005
Posts: 958
Location: Brazil
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Quote:
At 12 V, your solid state switch has at least 1V drop if not 2 or 3V. Multiply this with 50 - 100A and will get the loses on the switch. Plus the wires are bulky.
Good point...
Quote:
I assume you are using batteries. Just place them in series, lots of them.
Simpler way... |
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Regards,
Brunomusw
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Posted: Jan 24, 2012 - 02:19 AM |
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Joined: Feb 06, 2009
Posts: 836
Location: TN
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| Now I an thinking power tool, something like a large cordless drill. They often have a two speed gearbox, speed control, reverse switch, and powerful replaceable battery pack. They also have an adjustable torque clutch for driving screws. It could be used as a limit if something gets jammed. It might be a simple way to do a few tests. Just chuck it to an axle wheel. You might use two, one for each wheel for steering, with a couple free turning idler wheels. Similar to a zero turn mower. |
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