In late summer, a good friend of mine sent me a link to a CraigsList ad for a Zenn electric car about 30 miles from my house.

Wikipedia has this to say about the car:

ZENN (Zero Emission, No Noise) is a two-seat battery electric vehicle that was built by ZENN Motor Company of Canada from 2006 to 2010, designed to qualify as a neighborhood electric vehicle (NEV). It has a range of up to 40 mi (64 km) and is speed-limited to 25 mph (40 km/h).

The vehicle is based on the Microcar MC2,in production in France since the early 2000s, and produced under license from Microcar's parent company Bénéteau. The Microcar MC2, and the short wheelbase MC1, are sold in Europe with 500cc diesel engines, and are considered "Quadricycles" there.

Electric power is stored in six 12V lead-acid gel batteries, which has a recharge cycle of 8 hours. Valve regulated (low maintenance) lead-acid AGM cells were available at extra cost initially, then included as standard equipment in later models.

Also optional were a retractable fabric sunroof, air conditioning, floor mats, and audio entertainment center. The vehicle originally was built with a DC motor and GE controller, and in 2008 was modified with an AC motor and Curtis controller. The AC motor was stated to be better for hill climbing, initial acceleration, and overall performance.

The Craigslist ad was for a 2008 model Zenn that was in fairly rough shape. It needed new batteries, needed a new tail-light, had some body damage, and hadn't been powered on since 2011. It was untested and in unknown operating condition, mostly because we didn't have a pile of batteries laying around to test drive it.

I was told that it had been used by a local public-works department for meter reading and had a little over 3000 miles on the clock. The best part? It was cheap. And I mean crazy cheap. Go look up what these things typically sell for today. Take a zero (or two) off the end of that price and you can see how cheap it was. The lady that owned it (second-hand from the utility) simply wanted it gone. (Also, if you happen to see the bonkers original selling price, you'll see why it failed as a product.)

Well, I gave the lady a call and we agreed on a time to go over and take a look. I pretty much fell in love with it. I knew I wanted it, and I was willing to pay the price. A few bills exchanged hands and I was the proud owner of my newest money pit^h^h^h^h^h^h^h^h project.

Getting it home was entertaining. I couldn't exactly drive it home, and I couldn't leave it there. I talked to my buddy and he agreed to help me transport it.

Because of its small size, light weight, and the fact that you can roll it around in 'neutral' without electrics, we just put it on the back of a trailer! This picture is a great example of just how small it actually is.

You can also see some of the damage on the driver's side by the door handle. Apparently at some point in its history, someone backed into it, breaking the plastic on that side.

Once I had it back to my house, I got to digging into it. This is the new(er) model that has the AC motor and Curtis controller, rather than the older DC motor and GE controller. It has a Delta-Q QuiQ charger on-board. Has six 12v batteries ( two under the hood, four in the trunk) making up the 72v battery pack. It is about 10 feet long, 5 feet wide, weighs about 1800lbs, and has a 'space-age' frame made up mostly of aluminum, plastic, and glue. It seats two, and has a rear hatch with a surprising amount of storage space. It has heat, air-conditioning, a radio, seat belts, wipers, rear defogger, power windows, power locks, and central locking. It really does look like a real car. About the only 'modern' thing it is lacking is airbags. It has a top speed (governed) of 25 miles per hour, and with its original battery pack, should get 30 miles on a single charge.

I farted around with it for a month or two while I investigated batteries. What to get? Lead-Acid? Lithium? Something more exotic? Did the motor and controller even work? While pondering, I messed about with the old Interstate batteries someone had installed. The car originally came with six massive AGM Trojan batteries, 12V each, for a total of 72v. At some point in its history, they must have been replaced with cheaper Interstate flooded deep cycle units. I was trying to see if I could rejuvenate some of them enough just to get the needed voltages to see if the car would even move under its own power. The on-board charger could never get the cells going, so I assumed it was because the pack was so low. Interestingly, the manual indicates that if the pack voltage is very low, the charger won't do anything, and to use independent 12v chargers. It was rather comical to have six 12v battery chargers hooked to the car, trying to put a few watts into each of the old batteries, but eventually I had the pack up to about 60 volts, which apparently was enough for the car to go forward about a foot and backwards the same. It worked!

I eventually settled on getting the cheapest Lead-Acid deep cycle batteries I could at Menards, when they had one of their 11% rebates going on. Ended spending about $700 on six Exide wet-cell lead-acid batteries. I figured that I would go as cheap as possible and see if I actually end up using the car, and if I did, I could always upgrade later.

While I was hemming and hawing on what kind of battery to get, I went ahead and did some other repairs on the vehicle. I converted almost all of the lights to LED, with the exception of the main headlights and the side marker lights that are sealed units. I replaced the broken tail light and missing passenger side rear-view mirror, purchased from Bill at ZENNparts.com. I also fixed the driver side door window, and when I get my 3d printer going again, I'll see if I can't print up a replacement for the broken driver side door handle. The broken plastic body panels, I'll have to see, that's a bit more complicated, I've never done plastic repairs before.

Well, once I got my new batteries installed in the car, I tried out the on-board QuiQ charger once again, and it never really charged. It would always show a error when connected - pack voltage too low or did not charge enough during charge cycle. Strange. The cells all charged on their own, but not from the QuiQ. There was a solid connection between the two, but the charger wasn't doing anything. Odd. Also, expensive! I looked, briefly, into a replacement, and they are crazy expensive. In some cases, more than the cost of the car itself! I then looked into building my own, or buying an alternate charger. I quickly found that the 'proper' way to charge lead-acid batteries is a lot more complicated than I thought, if you want to get the most life out of the. And when you start looking into a charger that does 72v and ~50A, you start getting into some complicated (and expensive) parts lists. Alternate chargers were investigated and they were just as expensive, or more! Conversely, the QuiQ I already owned, was specifically designed for what I wanted to do, was already installed on the car, and was actually a pretty nice charger, if it was working. So, it was time to look into fixing the QuiQ.