How Much Electricity Does an EV Need?

by Haman

  1. How much electricity (watts) does the motor consume to run an electric car?

  2. How much voltage do I need to run a motor? Is there any range, or can I put as much as I can?

  3. How to increase the RPM of a motor? Is it by increasing the volts?

  4. Does a small generator provide the required power to run the motor?

  5. I am planning to use a 3phase AC motor (double shaft)…. Any suggestions to use different kind of motors?

Hi, Haman -

  1. The Ford Ranger conversion in "Build Your Own Electric Vehicle" uses 0.44 kWh/mile. I'd say it's pretty typical.

  2. If you're using an AC motor, the good AC conversions I've seen have run at 300 volts or so, using 12v batteries. People have run these motors at 120 volts, but are not happy with the acceleration. (Update: See the HPEVS AC-50 motor. It works fine at 120 volts.)

    DC conversions seem to have variable voltage, depending on how fast people want to go, how heavy the donor car is, what kind of bone structure it's got to support battery weight, and how much money they've got to spend on batteries. 120 volts will give you a pretty snappy car.

  3. When you ask about RPMs, are you asking about torque, does more voltage equal more torque? If so, then the answer is yes, pretty much.

  4. A generator will provide the quantity of power you need to run your electric motor, but not the rate of power you'd want for acceleration. So keep your batteries, and use your generator as a charger.

  5. You don't have that many choices, really. If you're going to use a 3-phase AC induction motor for your conversion, the best option is a traction motor, one that's used to move something. The best ones for cars seem to be coming out of old manufactured electric cars, like the Ranger EV, for example. That one's made by Siemens, I believe.

    Other choices include series wound DC motors, and brushless DC motors like the Rav-4 EV's motor.

  6. Good luck with your project, Haman!


Comments for How Much Electricity Does an EV Need?

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a few questions on EVs
by: Cjevy grillz

iim from Zimbabwe and I'm pretty much interested in building an EV, what I wana know 1s
1( his much distance can I travel using an ordinary EV let's say using a DC motor..
2) is there a way I can replace e motor controller with a device that can wrk the same eay as motor controler becouse myt not afford to buy aotor controller.

how do amps come into play
by: Anonymous

Say you run 120 volts how many amps does it call for. I dont know much about these electric motors but do know som electrical knowledge to me your voltage would stay the same but the more speed or load u put a motor under the less resistance in the electrical path and demand for amps would increase. Take a 2500 pound car with a 120 volt electric motor at 80 mph how many amps is that motor calling for. One of the last comment made it seem like the more volts the more power. You can take a transformer double your volts but now you have half as many amps. So i guess im asking how many amps do electric car motor call for

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