Nathan tried driving the "Ohmsmobile", as we called it, on a couple of errands. Turned out she only had about 10 miles of range.We figured that was because the batteries were so old, and had never been properly charged. That's probably the case; the Ohmsmobile had a "bad-boy" charger: a variac with a bridge rectifier to turn AC into DC. Bad-boy chargers are notoriously difficult to use. They can fry batteries in a single charge, under the right (wrong) conditions.
We tried to use it anyway. What the heck, these batteries were free, and we were already planning on buying new ones.
We found that the poor thing was weak. We think it was undercharging the pack, since we couldn't get it to read above 165 volts, even at its highest setting. (A fully charged 144v pack would read 180v.) That'll damage the batteries, too, although flooded batteries are quite tolerant.
The solution was a PFC-20 charger, for $1500. Ouch. Especially since I hadn't considered a charger in the budget. Luckily, the cheap Ohmsmobile purchase left enough wiggle room for this.
Then we discovered that the E-meter -- an instrument designed for EV battery monitoring -- wasn't connected properly. Or maybe its shunt had gone bad. Or maybe it was misconfigured. In any case, it wasn't displaying the correct voltages. And it was ugly.
Providence Strikes Back
We looked at lots of cars. I scanned the Reno cars.com classifieds from my home in Orlando for weeks. I especially wanted a Subaru Impreza wagon. We missed quite a few, and passed up one with a broken transmission. In retrospect, we could probably have made things work without a tranny.
Then Nathan's girlfriend found us a nice Honda Civic Wagon, my second choice. (A quote, from the email containing the pictures: "Honestly, I have had to master a great deal of technology to build your bucket of volts." Suck it up, Amy! Computers are the future! :-)) It was only two years older than my Prizm. The body was in excellent condition, but motor problems prompted the owner to let it go for $800. That was $200 under budget!
Her copper color prompted us to temporarily name her with one of my old chat aliases: The Electric Butterscotch from Hell. Butterscotch, for short. We figured we could use Honda Civic parts, which were widely available. We'd figure out later how wrong we were.
As you can see, there is a crack in the dash. We're considering replacing the dash with something entirely custom, and lighter. Other than that, though, the upholstery is in surprisingly good shape. Especially considering that it's a 16-year-old car!
We can probably keep this tachometer, and add a sender to the electric motor. It's not a good idea to run the electric motor over 6000 RPM, unless you've blueprinted it. With a tach, it'll be easy to keep track of.
But the real coup-de-grace is the back seat. As you can see from the picture on the left, it's in good shape. And, as demonstrated in the picture on the right, it opens to reveal the floorpan. This is elevated from the bottom of the car, with the driveshaft (this is an AWD model) going underneath. Since we planned to remove the driveshaft to save weight, we could use all that space for something else.
Like batteries. Measurements showed that 8 Optima Yellow Top batteries could fit in that space. We planned to cut open the top, weld a box to the bottom, and carry those batteries low to the ground, close to the center of the vehicle. That will lower the center of gravity for the car, which may improve its handling.
I guess everybody gets lucky once in a while.