Electric Car
william chan
Posts: 1,326
PJ Allen,
Your suggestion on using a cam for the gas pedal is ingenious !
I am always thinking of building an electric car this way.
If I cannibalize 4 electric scooter motors ( about 180watts 24 volts each ), what would be the best way to mount these motors
and couple them to the 4 wheels of a small car like a 660cc Daihatsu Mira?
Will the car be able to move?
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www.fd.com.my
www.mercedes.com.my
Your suggestion on using a cam for the gas pedal is ingenious !
I am always thinking of building an electric car this way.
If I cannibalize 4 electric scooter motors ( about 180watts 24 volts each ), what would be the best way to mount these motors
and couple them to the 4 wheels of a small car like a 660cc Daihatsu Mira?
Will the car be able to move?
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
www.fd.com.my
www.mercedes.com.my
Comments
4 motors, one for each wheel, "skid-steering"?
I used the cam idea to keep the·ferric-chloride solution moving in my circuit-board "etching tank"; one end is on a hinge and the cam raises/lowers the other end.
The enertiabike is due out soon.··A bit more practical than the "segway". ·www.enertiabike.com
The Kewet Buddy
http://www.elbilnorge.no/index.php?name=News&file=article&sid=7&bakgrunn=english
·uses a 13KW motor, and that car has been 'economized' down as much as they can to make it more affordable while still having a practical performance.
The 4 x 180W motors doesn't equate more than about 1HP.
The 'saving grace' with electric motors is that they can produce a lot more torque than a gasoline engine of the same rating. (They re also lighter and more compact.)
As for the idea of using 4 motors, that should be doable. You will probably need to have separate motor controllers for them, though, but that should help reduce loss when turning. (A differential isn't exactly a 100% efficient device)
I don't know the Mira model(only what I found on Wikipedia) but generally, the best place to mount the 4 motors would be in the hubs themselves. That would eliminate all axles and linkages completely.
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Post Edited (Gadgetman) : 4/6/2008 9:53:07 PM GMT
Although the engine/motor may be lighter in electric system the energy storage (batteries for electric and petrol for heat engines) for electric systems weighs a lot more so electric systems will usually end up heavier.
If you want to do some quick calcs this equation may be helpful
Power (watts)=force (newtons) * velocity (meters/sec)
or we can change force into mass * acceleration
Power (watts)=mass (kilograms) * acceleration (meters/sec/sec) * velocity (meters/sec)
Anyway, the Kewet Buddy I mentioned earlier weighs 400Kg without batteries, almost 800Kg with 10.5KWH of Lead-acid batteries, which together with a 13KW/72V motor gives it a range of 50 - 100Km(30 - 60miles, or so)
The Daihatsu weighs in at 590Kg or so(depending on model), with a gasoline engine.
Even if the engine and gearbox weighs in at 150Kg(I doubt it weighs much over 75Kg, really), and other systems like cooling also can be removed, it will be difficult to get it down to under 500Kg 'empty'
Add the weight of motor(s) and batteries, and it might just tip a ton.
That leaves the DMV or whatever national registry that exists where you live.
No, they probably won't make a fuzz about the conversion to electric, but they may want to talk about the weight and carrying capacity. (In short, the car must be 'recertified' and issued new papers.)
you may also need to talk to the imprter/distributor about the conversion work.
Some parts of the conversion may need an 'approval' from the manufacturer, and they usually prefer that these cases are routed through their representatives.
Anything that changes the brakes and suspension is 'iffy' without the right paperwork...
(Getting approval is easier than getting forgiveness)
Upping the engine power without the manufacturer's OK is one of the deadly sins, and will be rewarded with instant loss of license plates, but that's probably not an issue in this case...
Rebuilding a 2WD car to 4WD, though, IS something that definitely will need approvals.
I work for the Norwegian Public Roads Authority, and often come in contact with the 'DMV' equivalent here, and some of the stories...
These guys doesn't 'hate' hot rods, muscle cars or custom bikes. Some of them have 'rather nice' rides themselves. They are sticklers for correct paperwork and safety, though.
(In fact, a year or two ago, the department set up a hot rod exhibition at the 'motor museum'
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1. Four small motors, one for each wheel? or
2. One large motor in the engine compartment?
It seems that reduction gears are unnecessary with electric cars, is it true?
For electric cars, would brushless dc motors be better?
Gadgetman,
The electric car if successfully made would only be used for rides around the house, so licensing issues are not in my mind at the moment.
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www.fd.com.my
www.mercedes.com.my
Reduction Gears
Like Gadgetman and I indicated above, electric motors can produce useable power/torque at a lower speed than petrol engines. Whether you need reduction gears or not for either depends on the speed range you want and the RPM range that you engine produces useful power over. In a petrol car this range normally goes from about 1000RPM to about 4000RPM. In an electric motor it goes from 0 RPM to anywhere from 500RPM upto possibly 20,000RPM. However, in the ones you will be interested in it will probably be lower such as 1000RPM to about 4000RPM. But the power curve is fairly flat compared to petrol motors. So, depending on how fast and how steep a hill you want to go up will determine whether you need any gears. There are also some other things to consider like tire size. By the sounds of what you want though you won't need any gearing.
Brushless motors will be better (uses less power and is smaller) but the motor and speed controller will not be cheap.
Of course, a 4-engine conversion will require 'a lot' of rebuilding of the front and rear suspension.
In fact, I'd suggest that you first build a mock-up rig with just a seat, 4 wheels, steering and brakes, so that you can test the electronics and power requirements before going ahead with the real build.
(Make the rig so that you have a place to load up with sandbags to simulate the weight of the real car and batteries)
Who knows, you may find that the mock-up will·perform better than using a normal car...
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Try
www.sadik.net/gokart/
www.diygokarts.com/kart-plans/kart-plans-main.html
www.vintageprojects.com/go-kart/pdf/go-kart.pdf
www.kartbuilding.net/