Motor options for ultra-light car (around 800 pounds), including dual motors

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Spectra Ce
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Joined: 08/20/2012
Points: 3

I am a bit confused about motor options due in large part to conflicting motor information on different websites.
I am looking for something a motor/controller combination will make my 800 pound mini-car cruise at 65mph without the motor/controller burning up and hit about an 80mph top speed.
Extra acceleration would be nice, but not necessary.
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About to motor/performance confusion...for example, the L91 Advanced DC motor has a supposed peak of 71HP at 120 volts, but many sites list conflicting information about how many amps are needed to attain 71HP (and some list as little as around 48HP assuming around 500a from, say, a 550a Curtis DC controller).

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Meanwhile, oddly enough, compare this much cheaper (and supporting Regen!) drive kit like this MARS/MOTENERGY kit with a EMC-RT200 motor
http://www.electricmotorsport.com/store/ems_ev_parts_kits_EMC-RT200.php

...it manages a not-much-less than 48HP (minimum peak rating I've seen for the L91 at 500amp) 38HP peak with 400amps at 72V and apparently gets exactly the same 11.5kw = about 15.5 HP continuous rating...plus it weighs and costs much less.

So why (and why do people) tend to use the motors like L91 for small cars and not higher-end PM motors?
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Side question:

Is there any way to safely link two motors to a gear that drives the rear-wheel (in a situation such as on the back of a motorcycle)

A) With one controller (ideal)
B) With two controllers

...and could I get a reliable 32HP continuous from such a setup?

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I am ideally looking for an option with at least 16 continuous KW output and re-gen.

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reikiman
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Joined: 11/19/2006
Points: 8454
Re: Motor options for ultra-light car (around 800 pounds), ...

Welcome to the site!

Because you're talking about a lightweight vehicle the motor system should be similar to but higher power than the motorcycles.

As I said to you on Facebook - mount the controller on a large heat sink, and good air flow over the heat sink. That's what I have in my car, and the controller stays cool, even with 40+ mile drives at highway speed.

You may be able to send questions to Advanced DC ... as for why chose a DC over brushless? In my case I had the choice between a big 9" brushed DC motor and more expensive AC systems. I went with the cheaper choice. It would be nice to have regen, that's for sure.

The motor you linked to is 39 hp PEAK .. what is the continuous rating?

There are race motorcycles using the AC15 or AC20 kits (see electric motorsports' site) and doing credible racing. For a bigger-than-motorcycle vehicle maybe the AC30 kit would be right.

As for joining two motors together.. I've seen these scenarios:-

  • mounting two motors face-to-face shaft-to-shaft with a gear on the common shaft - this setup depends on each motor running counterclockwise to each other, and may/probably needs timing change in the motor. I've seen this setup with one controller.
  • mounting two motors in the same orientation, a small chain/sprockets between the motors, and on one motor you have a second chain/sprocket going to the wheels. I believe this can also be done with a single controller. FWIW the MotoCzysz entry in the 2009 TTXGP Isle of Man had three motors in this arrangement, but that bike broke a couple miles into the race
  • One motor per wheel, on a three- or four- wheeler. This setup I've seen with dual controllers. There is an option with this setup to implement something like a differential by manipulating the power level of the controllers as you go around a corner.
  • mounting two motors with the output shaft of one motor sticking in the rear of the other ... this requires motors that are specifically designed for this.
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