Electric car conversion: Project ForkenSwift

[MetroMPG]

Originally Posted by Christ

MetroMPG - are you considering doing any of the aero mods to this EV?

Nope! Remember, this is only a runabout. Average speed is probably somewhere around 20 km/h.

Weight reduction is always a good idea, but not by taking off the friction brakes! It's illegal & also less efficient to use battery power to slow the car as you mentioned. Plus plug braking requires a special controller with that feature built in.

Regen would be a nice feature, but there's no easy way to do it. It would be a fun project though.

Never mind aero or weight... I've figured out the next upgrade:Researchers Deliver Electric Motor Achieving More than 1 Million rpm

[Christ]

Shown to scale, that thing is about an inch and a half long... maybe a little shorter.. (looks to be about 40mm) The motor, that is.

One of the comments suggests that the drive gearing would be "lossy", however... that person is obviously not thinking... most vehicle transmission are three-stage setups anyway, in that there is a drive gear, and a driven gear, making the first ratio, then the initial driven gear becomes the drive gear, and the final drive (or rear gears) become the driven gear, making the second stage... can anyone guess the third stage?

Yes, your tires are essentially another gear ratio.

That said, 2nd gen CRX HF gears with Cat dozer tires (6 feet diameter, smallest) would be sufficient, I'd think.

Reducing weight could be acheived with laptop batteries, although somewhat expensive... I don't know if you could get them "recycled" and rehab them or not... but they're drycell, Li-Ion batteries, relatively light per their power output, and tend to last longer on cooler temps.. however, probably not excessively cold.

Not to mention the fact that they're deep cycle by nature.

PS, not to thread jack here, but I just got a CRX Si that I'm thinking of working on... I have a few thoughts for where I want the project to go, but EV's are something I've been toying with for a few years now.

[MetroMPG]

Finally finished the "index" of this long thread!

Now, newbies and veterans alike can skim the entire project more quickly, right in post #1.

http://ecomodder.com/forum/showthrea...nswift-33.html

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This day in ForkenSwift history ...

11-19-2006 - Disassembled & cleaned/de-greased the motor (hydraulic pump motors get greasy, apparently); reassembled & mounted on adapter plate, transmission

[bennelson]

Gal'der'it, Darin!

Stop raising the bar!!!


Now people will have expectations on mine and MPaul's!

[Daox]

Haha, very nice Darin! It'll be so nice to have an index you can do a search on instead of going through page after page after page after page after... well you get the idea.

[MetroMPG]

Originally Posted by Christ

Shown to scale, that thing is about an inch and a half long... maybe a little shorter.. (looks to be about 40mm) The motor, that is.

OK, so put a bunch of them in series!!

(Yes, I'm just kidding)

Reducing weight could be acheived with laptop batteries, although somewhat expensive...

That's the thing. Don't forget the prime directive of this particular project was: spend as little money as possible. Lithium isn't an option given that goal.

Essentially the car is a roaring success, given our modest design goals and its intended use. Any changes I'm likely to pursue will be small and inexpensive refinements rather than major changes.

EG: a controller bypass has the potential to improve efficiency by maybe 5-10% (when activated), and it wouldn't cost any more money (we have leftover components to do it). That's the type of thing I'd consider.

[elanmel]

Darin,

Add me to the list of folks who have read all your posts on this project--amazing. I've even started dropping into local forklift shops, and already have a line on a 48 volt motor/controller/etc from a 6 ton lift. I'm also trying to find a metro convertible or equivalent for my vehicle.

I think I need more power, though--I live in a big City (LA), and I would like to get up to 55 MPH at least so I can pop onto the freeway for a few miles when I need to. I'm only looking for 20-30 miles range, though, so I think 72 volts sounds right.

In an earlier message you briefly discussed overvolting your motor, but haven't done so yet. Do you think this would be possible with a 48 volt motor? The forklift guys say there are 72 volt units out there but they are rare, heavy and expensive. These forklift motors seem so beefy, that I wonder how far they really can be pushed and what can you do to help them survive if you pump more juice through them.

Also, there is a neat site where some guys are working together to do conversions of 92-96 Civics. If other lurkers out there are interested in working on forkenswift projects in parallel, maybe we can connect through this site somehow?
Civic EV Kit | Google Groups

[bennelson]

My Metro is a 72V 400 amp electric conversion.

Freeway speeds is asking a bit much for a basic homebrew electric car.

Go for the highest voltage you can afford, you wont regret it.

-Ben

[Christ]

I really want to build an electric rat... just to say "I did it"... I mean, I'd still use it, obviously. But why not?

Alas, it would definitely be a "cheap-mod" project though.

[MPaulHolmes]

Originally Posted by elanmel

Darin,
In an earlier message you briefly discussed overvolting your motor, but haven't done so yet. Do you think this would be possible with a 48 volt motor? The forklift guys say there are 72 volt units out there but they are rare, heavy and expensive.

My motor is a weenie 24v 60 pounder! I'm running it at 72 volts with no problems. I didn't advance the brushes or anything. If you have a 48v motor, feel completely secure in the fact that you can run it at 72 volts. 72v should get you up to like 45 mph I think. I don't think freeway speeds are practical at 72v. The current draw to be way too high. Well, maybe if your car is really aerodynamic. I have a ghetto super beetle, about as aerodynamic as a yeller monkeyturd (an un-aerodynamic one). At 72 volts, it's top speed is about 45 mph, but 35 is more practical to keep current down.