Battery Technology / Electric Vehicles

[colin340]

Originally Posted by John Gutmann

Not to shoot down your idea, but have you considered starting out with trying to convert maybe a go kart? This way it is smaller scale and less expensive. This way you can learn the same amount as you go along with spending less money. Then if/when you move to a automobile you know more. And maybe you can use the go kart to ask for sponsors too?

I like your idea, I have been wanting to do it for a long time, but as with any project money is the issue. How much working are you planning on doing? Becuase if you go with a motor pre wheel design there is going to be alot more work compared to just dropping an electric motor and transmission in. You will also nood to make a ton of parts. I have never personally done this but I have looked at alot of stuff online and for one person, a college student none the less, it is going to be a TON of work.

-John

good idea but is there a way to make it street legal

i found this http://blog.modernmechanix.com/2006/04/03/build-your-own-street-legal-kart/

[artdutra04]

Originally Posted by Qbranch

First off, what battery technology is the best? The most economical? Longest Lasting? I hear NiMH is good, but whats your say?

With batteries, weight is your biggest enemy. Keeping that in mind, I'd go with the Lithium-based battery trend that all consumer electronics have been going with as of late, as they are among the lighest of batteries.

Originally Posted by Qbranch

What kind of transmission? Leave the auto in and find a motor with a torque curve to match? Manual tranny electrically actuated? CVT?

Chances are, you probably won't need a traditional car transmission if you are using electric motors. Internal combustion engines develop their highest torque at high RPMs, and the highest torque in a car is needed when you first get it moving (e.g. slow RPM). That is why you need transmissions in a car with 3, 4, 5, or 6 gears.

With an electric motor however, you get your highest torque at zero RPM, which is perfectly suited for getting the car rolling. In an electric car, you probably won't need anything more complicated that a 2-speed transmission, if that. (The Tesla Roadster only has a two speed transmission, however it can run entirely in second-gear if the driver wants.)

Also, you'd get much better results if you use 4 small electric motors (one driving each wheel), than one giant one going through an auto/manual transmissions, differentials, etc. Most modern electric trains no longer have traditional locomotive units, but rather powered wheelsets spread along the length of the train, as this helps with the weight distribution and efficiency of the total system.

You can also use the motors for regenerative dynamic braking, however you'll still need traditional brakes. (Once you get below a certain speed, dynamic braking will stop generating enough electricity to recharge any batteries/capacitors, so you'll need traditional brakes to completely stop.)