# Motor question



## Jon (Jun 18, 2008)

First, I'm a newbie. I want to build an EV someday and I already have a donor vehicle. A 2001 Suzuki Swift 5sp that gets around 40 mpg so I'm in no hurry to convert. I'm waiting for lithium batteries to come down in price, but if I find a good deal on components I could start collecting them now. I wanted to build an AC system since I have an all freeway commute of 20+ miles each way and I was thinking about using a Solectria AC24EV drive system. The motor is rated at 43Kw max/14Kw continuous weighing 84 lbs. Then I saw an Unused Azure Dynamics(solectria) AC55 EV drive system for sale. The AC55 specs are 78Kw max/34 continuous and weighing 234 lbs. What would be the advantages/disadvantages of an over 2.5 larger motor?


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## major (Apr 4, 2008)

Jon said:


> What would be the advantages/disadvantages of an over 2.5 larger motor?


Hi Jon,

Advantages---more power, more torque, longer run time/less cooling requirements, maybe a little higher efficiency, more durable, etc.

Disadvantages---bigger, heavier, higher cost.

Bigger motor might eliminate need for multispeed transmission. You'd have to look closely at this.

A lot depends on your performance expectations.

You seldom see someone sorry they went for higher power in the motor.

Regards,

major


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## TX_Dj (Jul 25, 2008)

Jon,

If you're looking to keep your cost down (and it sounds like you are) then a DC powerplant may be a more appropriate choice. These systems are typically cheaper, though slightly less efficient overall.

If you used a 9" series-dc motor and a 500a controller with at least 120v pack voltage, I think you would have more than enough power to suit your needs, with far better than 40 mpg equivalent economy... and that's all from lead acid batteries. If you sink the remaining costs associated with the AC drivetrain into the battery price, you can come close to making up the difference with the amount one would pay for lead acid batteries in that car.

How many miles per day (on average) do you drive? How many miles maximum do you drive in one day? How many miles maximum in one trip, and how long do you stop over between those trips?

These are all important questions to consider in conversion. A majority of americans drive less than 25 miles per day. I drive at least 25 miles per day (commute round trip). But on some days I drive as much as 65 miles, but that is broken up in 12.5 - 38 - 12.5 with about 4 hours between each trip, which is a good amount of time to put some kWh back into the pack.


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## Jon (Jun 18, 2008)

Thanks for the replies. My commute is 22 interstate miles each way with an 1/2 mile 8% down hill at the end. My thinking is that if I want to commute at 55 - 60 mph then I should have a high voltage system at around 150-200 volts and if I want enough batteries for a round trip commute my Metro won't carry enough lead batteries. So, I need to wait for prices to come down on lithium batteries or a good flux capacitor to be developed. Price is not so much of an issue as long as my wife doesn't find out that I spent 20 grand on a hobby. If I could spread out the purchases she would be more accepting of my quest.


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## sailfish11 (Sep 15, 2007)

Jon, not sure if the used AC55 you wrote about is the one on Ebay. If so, one thing to consider is that AC motors need to have specific controllers(inverters) paired with them. As far as I can see (and I've looked a LOT), Electro Automotive is the only place you'll be able to get the controller that goes with that motor.

EA will sell you the controller, but if the motor is older (as the one on Ebay), you'll have to first send it to Azure Dynamics to have it rebuilt up to current specs (otherwise the controller won't work with it). That costs about $800. Then you can use EA's controller.

Since you're not in any hurry, maybe this is a good option for you and you can save ~$1200 off the price of a new motor. But before you buy, you should definitely check into what else you'll need to do to make it a useable motor -- maybe the one you're looking at comes with a controller.


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