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1370 Views 24 Replies 7 Participants Last post by  brian_
Hi, new to the forum. I want to convert a 1976 Fiat Spider 124 to an electric vehicle. Looking for a motor and would like suggestions. I am thinking of some kind of 48 V series wound DC motor with about 100 ft lbs torque and about 15 HP. Forklift motor maybe? I will drive through the 5 speed transmission that is in the car now. Probably LiFe batteries running 48 V. Also looking to see what kind of instrumentation is available. Some plug and play display for current, voltage and battery capacity. Will also want to monitor temperature.
I have not searched the forum yet so all the answers may be there. Just wanted to get the ball rolling. Probably start a thread on my project. I am in Windsor Colorado.

Thanks
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Large electric motors have plenty of torque at stall (Only need about 100 ft lbs) for initial acceleration. For passing at highway speed (High RPM) not so much. Check out a DC motor torque curve. Also, the 11.2 KW is only during level 65 MPH cruise, not average city and highway usage.
Torque gets you to ~30MPH, past that, 11KW is gunna be lethargic as a brick wall. Even the slowest communist car had a paltry 20KW gas engine and it wasn't meant to go over 40MPH anyway.

Torque is what you feel, but KW is what actually makes you go faster. They had steam engines that made 10,000ftlbs of torque but only 10HP because they only spin at like 50-90RPM. Trust me, one of those isn't outracing the poor 1,000ft-lbs of torque of a high end Tesla.

In terms of hydrogen fuel cell or supercaps, not really viable for either. Supercaps are hideously expensive in the sizes you'll need and well working with high pressure Hydrogen sounds like a safe time. If you want range extending: a series or parallel hybrid system will be the easiest bet, although still very complicated.
 

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His math is solid and he seems to have an understanding of margining for grades and acceleration. Keeping the gearbox should give him around 0.5g in 1st gear with 100ftlb at the flywheel, which is not your commie car acceleration. He's not out to build a 2 second 0-60 car...good on him for the discipline not to feel he has to.

That car is tiny and light, so good for low rolling resistance. 1/3 that of your beloved "Tesla", which the Model S uses 20kW at 60mph.
 

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In terms of hydrogen fuel cell or supercaps, not really viable for either. Supercaps are hideously expensive in the sizes you'll need and well working with high pressure Hydrogen sounds like a safe time. If you want range extending: a series or parallel hybrid system will be the easiest bet, although still very complicated.
Supercaps are necessary to work with the impedance of a fuel cell for vehicle propulsion.

While I hate hydrogen as a greenwashed way to sell methane, it's clear OP knows his poop and you do not.
 

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One more thing...parotting "Leaf" all over the forum as a preferred choice is noble, yet misplaced, in a car like this that has a solid beam axle in the back...way too much butchery to make it IRS to work a Leaf drive unit, unlike a Porsche or FWD car. Using just the motor about halves its output rating when driving a transmission input shaft.
 

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I am in the process at looking at the possibility of a Hydrogen Fuel cell with a High Power storage capacitor. I do not believe that Lithium is the ideal way to go in the future. Hydrogen has a higher power density but presently requires large volume for storage and there is very little infrastructure.
You have just departed from the world of do-it-yourself EV conversions into either a commercial world with funding in the millions of dollars, or just into a fantasy. People have built fuel-cell road vehicles for decades, and there are always several serious projects building more variants of them; they generally don't use supercapacitors and they are not done with hobby budgets. There's a project currently underway here in Alberta building two trucks with 63,500 kg (140,000 lb) gross combination weight rating to tow B-trains of semi-trailers with 700 km range, with a project budget of CDN$18M... all as a way to use natural gas without carbon emissions.

If you want a hydrogen fuel cell electric hybrid car, just buy one from Toyota, Honda, or Hyundai... it would be a better car at lower cost, and much safer, even if you did some DIY replacement of the perfectly functional lithium-ion battery in that vehicle for an ineffective bank of capacitors.
 
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