Battery Technology / Electric Vehicles

[Qbranch]

Well... hey wow lots of replies. The Astro van wasnt set in stone, just had one available for free. I like the idea of trying a smaller vehicle first, also thanks for the links to info websites.

To be honest I am just playing around with the idea for now... looked through some of all your links you gave me and came up with about 8~11 thousand dollars for the conversion.

Anyhow... I think you'll be seeing an electric go kart around this summer in indy...

Thanks again guys,

-q

[dtengineering]

So did I see you said you want to race electric cars...?

You could start with a relatively low-cost (say a couple grand, depending on how fancy you get) Electrathon race car. We used to build them back in the day before we became team 1346. I've put some video up on youtube here: http://www.youtube.com/watch?v=yjO6xp-Tz8Y

Or you could go "big time" and do electric drag racing: http://www.nedra.com/

There are many, many articles available on the web concerning electric vehicles and mods, etc. While lithium batteries are cool, most conversions still seem to be based upon lead-acid, simply due to the fact that you can get huge amounts of current for relatively low cost.

If you want to work with lithium batteries without breaking the bank, may I suggest using them for radio-controlled electric airplanes? For a few hundred bucks you can build a plane with a thrust to weight ratio greater than the F-22. We are building them in my Engineering 12 class and tried replacing the NiMH batteries with Li-Poly today. We can now launch the airplanes straight up... no taxi... no runway... just straight up like a rocket. Now THAT is cool.

Jason

[EHaskins]

If you want to retrofit a go-kart, you could pull the drive and controls from a used electric golf car. Most electric golf cars run 24-48v, 3-5hp motors, and have max. speed of ~20mph.

I know you can pickup used golf cars very cheap, if they have bad batteries.

If you wanted to spend a little more you could replace the analog controls, most older golf cars use, with digital controls.

[John Gutmann]

Well You could easily make a VERY powerful electric go kart from 4 AM 2 CIM 2 speed shifters and 8 small CIM motors. If you saw the video that was posted a while ago ( I don't remember what team ), but they took an old swerve drive module and was driving people around with 1 CIM motor. The frame should be brutally simple. Get a Kitbot frame, I personally would trust it, as the cross section of the rails has great structure vertically. It is easy to mount to and a nice size. You can then use 6 of the 18 AHr Batteries to power it. That should be fine for a nice short ride. You can do a 4WD config with u joints on the front wheels for the drive or do a 4wd with 4 back wheels or chain up all 4 transmissions to the back 2 wheels (my preference). And run a simple steering mechanism on the front. No need for fancy rack and pinion steering. I have thought about doing this ALOT in recent years, but once again lack of money ahs stopped me.

Another thing you could do is go talk to a mini baja team in your area and see if they would be interested in donating a car to the cause.

-John

[VEN]

Nimh batteries are NOT the way to go. I have recently turned my back on them when they required constant peaking for max output. They are heavy, loose charge very fast, and must be cycled around every 20 days or so. Lipos is what I use now for my r/c cars/boat/planes/helis. As dt mentioned, with lipo you hold the plane in your hand and give it not even 100% full throttle and just release it. A 6 cell 3800mah NIMH pack weighs a pound, a 7.2V 5000mah lipo pack weighs half of that, holds its voltage longer and allows for larger current draws. However, lipos are dangerous if not taken care of. They do blow up and they do set people's cars/houses on fire if not kept in safe spots. They only do that if cells are unbalanced, or have been damaged but the damage went unnoticed. They are also very expensive . Your idea is a great one, as a matter of fact about 2 weeks ago I started thinking of the same thing, but instead converting something like a hatchback. I looked into it and it seems that a DC motor is more optimal than AC. A brushless motor of that size would be more expensive than brushed, and probably hard to find. DC brushed are sold at websites like this one http://www.electroauto.com/

I'm experimenting with hydrogen right now

Vova

[Protronie]

Originally Posted by VEN

However, lipos are dangerous if not taken care of. They do blow up and they do set people's cars/houses on fire if not kept in safe spots.
I'm experimenting with hydrogen right now

Vova

You worry about a battery blowing up?
And now your experimenting with hydrogen?
Good luck on that one!

Ba Da Bing, Ba Da Boom!

[Adam Y.]

I looked into it and it seems that a DC motor is more optimal than AC. A brushless motor of that size would be more expensive than brushed, and probably hard to find. DC brushed are sold at websites like this one

I don't particularly like the distinction between AC and DC because of the fact that brushless motors can be run off of both types of power. In an AC implementation you apply an alternating current with an equal phase distribution. In an DC implementation you switch the phases in a certain order just with a DC voltage you can get from a battery. In the long run brushless motors will in fact be more cost effective than brushed because of issues involving wear and maintenance.

[VEN]

Oh I never said brushless isn't the way to go because...well...it is! Like you mentioned, no maintenance, more efficient (90%+ efficiency) When I was talking about AC and DC I was talking about brushed, sorry.

I work in a well ventilated area with the hydrogen (aka outside). I'm not producing that much of it either.

[Adam Y.]

Originally Posted by VEN

Oh I never said brushless isn't the way to go because...well...it is! Like you mentioned, no maintenance, more efficient (90%+ efficiency) When I was talking about AC and DC I was talking about brushed, sorry.

I work in a well ventilated area with the hydrogen (aka outside). I'm not producing that much of it either.

Ahhh.. Now I understand This whole entire issue of motors is kind of confusing for me just because there are so many types. One of the more interesting types I've seen is the switch reluctance which has no magnets inside of the motor which results in no cogging.

[Viper37]

Ignoring the other posts, dont use the Astro Van as your platform.

Astro's are heavy monsters and are about as aerodynamic as a brick wall.

You also dont want to use the van because vans are a pain to work on.

Just my 2 cents.

[Protronie]

Originally Posted by Qbranch

Anyhow... I think you'll be seeing an electric go kart around this summer in indy...
-q

Back when I was in Kentucky, we used them Cushman electric trucks for getting around. Well my supervisor and the supervisor from the other shop were in the habit of trying to out do each other in tweaking their shops Cushman to be the fastest, or have the most pulling power.

Ah the memories of cushman drag races in the tunnels on 3rd shift....
and the stinking blue cloud of smoke when you burn up a motor.


Anyhow, you can find old Cushman's for a grand or two... from there you can build all kinds of things out of them.

And if you want to race... I got a buddy in Lexington KY with the fastest Cushman you've ever seen. I could set up a race... hehehe