Hit the EV conversion motherlode
 

In light of recent events involving my proneness for injury involving my finger (I still have all of them), a table saw, my mother's motorcycle, my ankle, my mother's motorcycle's muffler, and my leg...I've been perusing CL for lightweight auto bodies and anything else useful in an EV car conversion. It rains here a lot, and I'm carrying computers around all the time, so I've reconsidered making my own forkencycle and decided to pursue a car instead.

A couple days ago, I found this on CL. If the link is gone it's a $500 72V electric "heavy duty golf cart material handler" with an ADC a89-4001 motor that was allegedly used at a GM plant to transport employees, toolboxes, and welders.

My girlfriend reminded me that we need to be saving up for a house, and after agreeing, I decided to compromise by offering $300 for the thing (I didn't expect the seller to accept the offer), and it flew!

Instead of going to fetch it when I expected to, I spent the whole day fixing the lights on my father's dolly trailer, and getting a temporary inspection sticker. The next day (yesterday) I set off on an epic journey to Grand Island NY. There aren't too many places in New York State that are farther from Binghamton than this island I hadn't heard of up until a few days ago.

On the way I saw some pretty cool stuff
http://i40.tinypic.com/28h0gns.jpg
http://i44.tinypic.com/2wcnnea.jpg
And after about 4 hours of driving, I got the loot:
http://i42.tinypic.com/s6n8kk.jpg
After another 4 hours and an average trip 18mpg on my father's '00 V8 Tundra, I arrived at my parents house to take a couple photos and drive it up and down the street.
http://i43.tinypic.com/300ci2r.jpg
http://i44.tinypic.com/2j6ag6a.jpg
http://i40.tinypic.com/fu05kn.jpg
That motor almost looks smaller than the hydraulic pump motor I ripped out of the junkyard forklift, just rated at a higher voltage.

Step 2: Get a host car.

P.S. It's been an epic last couple of days, so I felt inclined to make an equally epic post - sorry it's so verbose.

Pretty sweet loot! Looking forward to what you do with it.

Mmmmm... Is that the delicious smell of epic conversion? Can't wait to hound you for more eye candy and posts... Good luck.

Motor, controller, charger, decent batteries... 300 bucks! Nice.

Grand Island is interesting too - I didn't know about it, right there in the middle of the Niagara River.

Remind us again: what are your goals (range/speed)?

Fascinating! Best of luck with it! I saw a very similar vehicle fully restored as a mini-bus. Interesting base! Enjoy!!

So what are the Volt and Amp ratings on the motor? Also, how much does the vehicle itself weigh, how much hauling load is it rated for and what is it's maximum rated speed at 72V? How many Amps is the Controller rated for, and does it have a variable Voltage or a single 72V rating?

I don't expect you to have the answers immediately, mind...but once you do you'll be able to make some good guesses concerning the size of your new chassis, maximum speed and range, etc. Also, I recommend you take the take the 72V controller to a Golf Cart or other EV dealer-many controllers for powerful, low-speed vehicles have a built-in governor at the controller which can be bypassed/eliminated by an expert.

Three hundred bucks-great deal!

awesome deal for the parts/money.

First thing I'd do (just to tinker with it) is to strip it down as light as possible and see what she drives like at the current weight.

Do you have a battery choice in mind? I'm trying to work out a GB for some LiFE MGPO4 batteries from Valence which would provide you with better range, power all at a lighter weight. I think the cost may be a lot higher though. Just have to wait and see.

Looks similar to the 36v utility carts I used to use. Similar carts are used at airports for towing luggage carts, etc. If memory serves, they were made by taylor-dunn and would go about 15 MPH, mostly because of the high gearing (13:1 or so) and tiny 8" tires. They had contactor controls for low, medium and high speed (speed being relative, of course 8-)

The 36v motor should have no problem at 48v, and might work at 72v but probably nothing higher. Should make for some fun experiment material. Congratulations on the find!

Wow!!! Great deal, I believe you can do a lot with this already!! Keep us posted on futher developments.

Any news? Has the Great Tear Down begun? Found a recycler to take the bones off your hands and recoup some of the cost?

So many questions in this thread :)

I plan to achieve 45mph max and hoping for something like a 20-40 mile range, but I think this could go higher. It's going to be a simple around-town car that I would need at minimum to do a 20 mile round trip at best, but I would like to go a little further if I think of other errands to run on that worst-case scenario trip.
The motor is rated at 36-72V, 6 HP, 27 HP peak. Don't know the amperage.

I have no clue what the vehicle weighs, its pretty light. I'd guess less than 1000 lbs. It is NOT very fast, but this is in part due to the tiny little wheels, and the fact that it was designed to run indoors at a manufacturing plant - it's not supposed to go fast. I took it up an incline and it did not do well - it slowed down considerably, but it did still make it eventually. I hope this means the batteries are still in okay shape.

About those batteries... they are all 6v, so this thing was mis-advertised on CL (although I don't blame the guy). The motor is running at its rated 36, so I don't know how it will act with 72, nor do I know what I'll do about the battery situation.

I haven't taken a look at the controller - one thing I know is that there are (as TomEV mentioned) 3 "speeds" based on pedal position, and 3 corresponding coils under the seats that get VERY hot.

I've actually been unusually busy lately making money or whatever - some old BS :-P In light of my slightly unfortunate battery diuscovery, I'm going to wait to tear it apart until I:
1.Get a better look at the controller and find out if it has a voltage rating and/or a governer on it and get that removed.
2.Get more batteries and run it with more batteries on it to see how fast it goes

I'm still looking for a host car, but no rush on that. :thumbup:
more to come,
will

Oh! Sounds like you've got a simple contactor controller, with possibly 1 speed wide open (direct connection) and two lower speeds "controlled" with some combination of the resistors (potato boilers, as some of the Citicar people call them).

I thought you had a PWM controller.

Depending on your tolerance for 'possible' burn-out of components, since you appear to have a contactor set up it will be easy to test it at a higher voltage. Coil -type contactor setups normally do not have a series/parallel system, and run the full pack voltage through the resistors (coils) to move at slower speeds.

Other, obsolete 3-speed contactor systems use 2 batteries (low, 12v) 4 batteries (med, 24v) and all batteries (high, 36v). You probably don't have this type of setup because you have resistor coils.

The most sensitive part will be the contactor coils (part that pulls the contactor closed, not the resistor). If they are running at 36v (full pack voltage) they won't like to be operated at 48v or 72v and will tend to burn out very quickly. If you can trace back to where the contactor coils get their power, you can re-tap the traction pack at 36 (or 12 , or 24v, whatever they use) to make them work with a higher voltage pack. The two or three amps won't be a significant mismatch across the battery pack considering your motor uses about 150 amps.

Aside from that, you can temporarily install old 12v car batteries for a test to see how it will do. 4 for 48v, and 6 for 72v. You may be able to sweet talk a junk yard or battery store into 'borrowing' a few old batteries for a test before you buy a whole new set...

One last note - If you replace the batteries with a higher voltage set, check where your 12v power (lights, etc.) comes from before you turn anything on. In many utility carts, 12v is tapped off from two of the traction batteries. You won't want to put 24v to your headlights!

... and maybe when it grows up it can impersonate this beauty! ;) Taylor-Dunn I think:

So here's a general good-to-know question: In a host car where I intend to use an existing transmission, what would be better to look at if I'm looking at cars with virtually the same curb weight - more torque or less torque? It just crossed my mind how light those older 3 series BMWs are, and how light they would be minus their HUGE engines. Would this be a bad transmission to work with, or better to propel the car up to my low top speed goal? The pickins are slim for little cars around here like metros, MR2s, CRX, and even the less "famous" ones. I did find a $150 97 metro lsi hatchback shell sans tranny - I am carefully considering this because it would save me the work of ripping an engine out, and all I would have to do is go to the junkyard for a similar transmission. (The problem is that I'd have to take another long road trip to go get it.) Would a transmission like the metro's be better for an underpowered motor like the one I plan to use?

hmm..., what is the track width of that material handler? I'm wondering if you can just graft the drivetrain/wheels/suspension off that on to the rear underside of the lsi? And have more room for batteries under the hood.

Potato boilers, lol.

The track is pretty thin, probably even thinner than a metro wheelbase. Even if I could get that to work (since the drivetrain is pretty small on the cart) it's geared so slow with only one gear (and I doubt it's CVT :-P) that i don't know if I could convince it to go as fast as I want nor up hills quickly enough to be safe. I will look into this a bit more in depth. I'd still really like to know if anyone has ideas on the optimal transmission for my application.

fyi, i just measured a 98 metro, it was ~59 inches wide at the rear as measured at the outside of the tread.

$150 for a metro if it has a clear title would be a pretty good starting point. You can also experiment with your existing cart a bit too, like weigh it down to as much as a metro and see how it performs.

Do you actually have a lead on an old BMW? I didn't think they were very light (of course, you know my reference point).

As for transmission choice, unless you're planning a drag car I don't think you need to worry about the torque capacity of one over another. It shouldn't sway your decision all else being equal, I mean.

old 3 series BMWs are actually easier to find around here (on CL) than typical EV conversion finds. As for that metro lead, I'm going to wait on that, because I don't think many people would bite. If they do, I'm not too concerned, something will come up eventually. Today I actually got not one but TWO CRX leads. One is $100 and the other could be free or equally as cheap. I know I'm going to be able to get a sweet deal on whatever my host car will be, so I'm anxious to bite, but not in a hurry. Still haven't made it back up to parents house to measure the wheel base. I appreciate all the input and feedback, guys.

The saga continues: I didn't measure the wheelbase, but I'm sure enough that I'm going to have to rip the components out and convert a small body. I did finally get around to overvolting the system. The first attempt was fruitless - the "potato boilers" evidently have one maximum output in mind, and doubling the pack voltage did nothing. That was several weeks ago. I made it back up again to the rents' house where the cart is being stored this last friday (6/19 for a note-to-self tick on the timeline of this project). I circumvented the potato boilers and hooked the pack and motor directly up to the "forward, neutral, reverse" lever, which is really a sort of contactor that switches which field poles on the motor to run the voltage through. This also circumvented the "key" system, which was connected to the array of potato boilers. I didn't take photos of this, because it's very straightforward. I effectively made a "GO" switch out of the FWD/REV lever. I hooked 3 12v batteries in series with the rest of the pack of 6v batteries. I read extensively on this before doing it to ensure that there was no danger - if different voltages are added in series, the pack assumes the amperage of the "weakest" battery, and just drains it a little quicker than normal.

The first attempt yielded a much faster cart - I drove it up the short road my parents live on, and couldn't make the turn to return, so I used reverse. This immediately made one of the old EXIDE batteries pop a cell and steam and bubble a little. I took it out of the pack, leaving me with ~60v. This actually made it go even FASTER and I nearly fell off when I popped it into FWD. 0-60 (volts) in a millisecond. This put a smile on my face and concluded the test. Given the results, I think maybe even a 96 or 108 volt setup would be sufficient. Even a light car chassis would be much heavier than the cart, but that thing TOOK OFF at 60v. The motor wasn't even a little warm after the short test - I think it could take the punishment I give it with a bit of cooling. I'm still wondering if mixing voltages will be feasible in the actual working conversion. It seems like 96 or 108v worth of 6v batteries would be too heavy for the gvwr of a little metro or similar light bodied shell, but I haven't crunched any numbers yet.

Here's what the setup looked like after I took away the jumper cables. I was too excited to take "progress" pictures, and I didn't want to touch my camera with greasy hands. The exide in the middle was the one that blew. You can kind of see the wetness from the acid on the side of the battery closest to the camera.
http://i39.tinypic.com/33djwq1.jpg

Fun!!

The Exide that blew probably already had a weak cell. The cell reversed polarity when its voltage was drawn down low enough, with the result that current passing through the battery began charging that cell.

That explains why it was bubbling furiously - you were probably stuffing a lot of current through it. Maybe 75 amps? 100?

It makes sense that removing that battery from the string made things go faster, because you effectively took a big battery charger/resistor out of the loop!

Latest development: I found this 91 civic HB on the local (pheew) craigslist for 350. Bought it the same day.
http://i26.tinypic.com/dh6f69.jpg

It doesn't run (HAH!) and it came with a bunch of misc. D15B1 parts (any takers?).
http://i31.tinypic.com/30sykag.jpg

I wanted a CRX or something equally as slick, but I was tired of scouring ads filled with GSR swaps and body kits. This is a pretty cute car. It didn't have a title, so I'll have to sort that out first, which shouldn't be terribly difficult. The next real step is probably interfacing the motor to the tranny.

I'm not sure if it still works, but I used to title cars by writing a bill of sale... NY used to write titles based on a BOS from the seller, if the car was bought out of state. Then, when the person got the title back, I'd have them sign it and send it to me in the mail, so I could go to PA notary and xfer it. Cost me about $50 total, which is cheaper than going through all the BS to get a title from those "title companies".

I also have family in GA... GA used to be a non-title state, I don't remember when they started using titles, if they ever did, but if you know someone in GA, it's really easy to get a title. You just have them sign, date, and address a BOS... any state will accept it, because GA doesn't use titles. (So long as the vehicle doesn't have a title on the books. PA's titling system clears all titles from the books after 5 years of non-reporting.)

If you run into any problems along the way it turns out I'm local to you, in Binghamton all the time. Love any project that involves an electric motor.

Word to the wise; the motor-to-transmission adapter is the most critical of the whole build, spend your time getting that perfect and the rest is smooth sailing.

Oh, consequently, I have lots of parts for your car, including rear disc brake conversion, 2" lowering springs, so on and so forth... so if you happen to need a part for something, let me know, and I'll check and see if I have it.

I also have some 15" steel wheels from a Saturn that are 4x100.

This story continues here.