Hit the EV conversion motherlode

[Wonderboy]

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.

[MetroMPG]

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!

[Wonderboy]

Latest development: I found this 91 civic HB on the local (pheew) craigslist for 350. Bought it the same day.


It doesn't run (HAH!) and it came with a bunch of misc. D15B1 parts (any takers?).


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.

[Christ]

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.)

[AmpEater]

Originally Posted by Wonderboy

Latest development: I found this 91 civic HB on the local (pheew) craigslist for 350. Bought it the same day.

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.

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.

[Christ]

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.

[Wonderboy]

This story continues here.