Ben Nelson's Electro-Metro Build thread

[bennelson]

Greasy FUN! - Ok not really all that fun. Still pretty cold out right now to be covered with WD40 and using metal tools.

I finally was able to get the end off the big double-ended forklift motor.

It was INSANELY greasy/grimey/dirty inside.

I degunked it as best I could with my fingers and a palate knife. Then just hosed down all the parts with WD40. Should help degrease it and keep from surface rusting while it is apart.

Inside is four electro-magnetic coils and four matching brushes. The brushes are pretty beefy sized, but are VERY worn down and will definately going to need to be replaced.

When I first tested the motor on 12V - I could see a little bit of arcing off one of the brushes.

The commutator looks pretty worn. I think the brushes were so worn down that they were digging in funny. I think brushes are like brake pads - you just need to wear them in a little bit before everything fits really well, right?

The middle chunk of motor, which holds the field coils, is 7 inches long. (on the left in the photo on the top)

Now that I have it apart, I can see if somebody like Jim Husted will take a quick look and offer advice.

You can see more photos of this motor torn apart HERE

[WaxyChicken]

Wow, what a mess.

I can't wait for you to share what you learn.
It may help me when i take care of mine.

BTW, a little something about motor's brushes that i found interesting and thought to share (just in case)

"...Now, "wear" is a very subjective term when related to motor brushes. In fact, "wear" often improves a motor's performance in strategic ways. Going back to the spinning globe and erasers, the rectangular erasers against the spinning globe do not ideally conform to the globe. However, imagine holding the erasers on the spinning globe long enough that the erasers wore to conform to the globe's surface - then contact is optimized. In this way, initial brush wear - or, break-in - is used by some motor manufacturers to optimize motors in the production process - that is, new motors are run for several hours to "set" the brushes. Further, most well-used powerchairs run quieter in the more-commonly traveled forward direction than in reverse because the brushes wear optimally in the most traveled direction (in a quiet setting, try driving your powerchair forward, then reverse, over some distance - the change in pitch that you'll likely hear is the orientation of brush wear)."

[Meph]

Good luck with this project, your bike and car have kept me inspired to one day convert my car to an electric

[dremd]

Originally Posted by WaxyChicken

Alternatively, you can make two (120?) v plugs for the car's 240v charger input.
a measure on one of the 120v currents *2 will likely get you very close to how much juice the charger pulls. Just a thought.

I tried this with a well pump It did not work, It would appear that the (mine anyway) Kill A watt uses the Neutral line to measure wattage.

[RarestAce]

I just finished reading your post and i cant wait to see how the car turns out. Whats going on with your car so far?

[bennelson]

Not too much going on with the car lately.

Mostly, I have been busy with work and taking the electric motorcycle out to some EVents.

I was able to make it to the last Chicago area Electric Auto Association meeting. One of the guys I rode down there with works for a carbon company and is working on getting me some new brushes for the big forklift motor.

I need to see about getting in touch with that group of guys about doing a "work on electric cars" afternoon sometime soon.

Next thing is designing the coupler and adapter plate. I am now leaning towards a system similar to what is used in the FORKENSWIFT - clutchless with some sort of Lovejoy style coupler.

I also need to get an expert opinion on the state of the main drivers side wheel support. Do I need to reinforce it by welding something on? The passenger side looks good, but I am not sure about the drivers side.
While I have the engine and transmission out seems like a good time to work on it.

There have been some 72V controllers for sale recently on Ebay at reasonable prices. That may be a good enough reason for me to go with that voltage.

I will keep you all updated whenever I actually DO some more work on the car.

[Nerys]

Wow that looks cool!! I wish I could find metro's cheap like that I want one so badly! any chance a project like this could do 45-50mph and go 65 miles?

How about an old VW THING as a host? I happen to have one. SURE its not aero but its so damned neat looking (and I already have it)

[bennelson]

Old VWs are very popular for electric conversions.

Right now, I am thinking about doing a 72 volt system. I took a good look at Dr. Larry's Electric Metro page, and it's a pretty nice setup.

His can get up to 70 mph on a fresh charge. I am keeping the manual 5-speed transmission and expect to be able to go 45 mph easily.

Range is going to be less. I am shooting for 30 miles. Lead-acid batteries just don't hold a lot of energy for their size and weight. You can convert a car that would go 50 mph and go 60 miles, but you would need a LOT of batteries. And it's diminishing returns. The more batteries you have, the more weight you are lugging around.

It seems to make more sense to design around more modest speeds and ranges, then carpool or take a fuel efficient gas car for long trips.

[Nerys]

I understand but an EV is only logical if it can make a dent in my gas bill :-) My commute to work is 54 miles each way (charging at work is no problem) thats why I need 60 miles. IE if I had one that could reliably do 60 miles it would save me $3500 a year in gasoline!

Just how many amps would I need to go 60 miles? How do I do such math? I am tinkering with the idea of using NIMH batteries specifically 10 or 12 amp D cell NIMH's ie 600 cells would give me 72volts and 100amps. With nimh I can use ALL of the power no 50% usage limit as with Leads. Then the other question. How the the heck would you charge 600 cells :-(

[bennelson]

You are getting WAY beyond my skill level.

One thing I am doing with this project is just keeping it real simple.

You CAN build a car that can go over 100 miles in a day, it's just not part of my plan. You start to need a lot of batteries, higher voltage, etc.

Take a look through the EV Album and see what you find in there for higher range vehicles.

That's how I built my electric motorcycle - just looked at what other people had done, and what parts they used, then built something similar.