This EV Swap Is Better Than a Tesla

My first car was a 1960 Morris Minor Traveller station wagon that my father had purchased when I was little. He used it until it wore out, and it became my hand-me-down car when I was old enough to drive. Growing up, I had to keep the Morris running myself or I wasn’t going anywhere. My dad was a jack-of-all-trades—he once yanked a broken automatic transmission out of his early-sixties Ford F-100 pickup and fixed it himself—and he passed on that go-to-it mentality to my brother and me. We love to tackle new projects.

Eventually I left home and started driving other cars. In the late eighties, I ran into a guy who had a Morris Minor truck sitting in his yard that he didn’t want anymore. It was so similar to my Traveller wagon. We worked out a swap for an IBM PC that I had lying around, so then I had an old Morris deteriorating in my yard for the next decade.

Even back in the early nineties, my brother and I talked about building an electric car, but the technology just wasn’t ready yet. The batteries were too heavy, all acid and corrosion. But I’d look out at the Morris in my yard and think that it would make the perfect electric car. Here’s how I converted that tired old gas guzzler (well, as guzzly as a little British pickup could be) into a smooth, efficient electric vehicle—and how surprisingly easy it was to pull off.

after pulling out the old engine and transmission and all the lines and hoses that those parts require, there was plenty of room under the morris minor’s hood for a couple of batteries more are in the rear and a small motor controller

After pulling out the old engine and transmission and all the lines and hoses that those parts require, there was plenty of room under the Morris Minor’s hood for a couple of batteries (more are in the rear) and a small motor controller.

Ian Allen

The best donor cars for EV swaps are often older, lightweight vehicles with a manual transmission. New vehicles make a conversion almost impossible. They’re so complicated—with countless interconnected components, computers, and sensors—that it’s hard to make sense of it all. But I knew the Morris inside and out from wrenching on mine as a teenager.

By 2014, the technology and parts to do an electric conversion were becoming available. This was just after the Model S came out, and I went to the showroom at Tesla’s factory in Fremont, California, to see it. That got me excited to convert the old Morris into an EV.

Even though they are simple compared to modern vehicles, old cars still have a lot of moving parts. There’s the engine and transmission, differentials, and all manner of pumps and fuel lines and the like. An EV, in some ways, is much simpler: There’s the electric motor to power the wheels; a motor controller, which is the brains of the operation; and a battery to power everything. At a very basic level, that’s all you need to get going.

While you could use a motor from a donor EV like the Nissan Leaf, those components are deeply integrated into a modern car’s electronic controls and constantly receiving feedback from different sensors in the vehicle, such as the traction control and antilock braking systems. You can’t just use one in a conversion without spending a lot of time dissecting everything and tricking the motor into thinking it’s in the right car. Instead, it’s better to just buy a motor specifically designed for this, because all the work has been done already.

The first motor and controller I tried for my Morris came from a company called HPEVS, which originally made electric propulsion equipment for golf carts. I picked the AC-51 induction motor, which is made for lighter vehicles like mine. It makes around 88 horsepower and 108 lb-ft of torque. That might not seem like a lot, but it’s not a large vehicle, and the most powerful Morris Minor made only 49 horsepower from a tiny 1.1-liter engine when new. It cost me about $5,500.

the simple and light  morris minor made an excellent donor vehicle for an ev swap

Using your old transmission in your EV conversion is a simple way to drive power from your new motor to the wheels. There are off-the-shelf adapter plates that allow you to mount an electric motor directly to the transmission (though some cars may need custom-made adapters).

That wouldn’t work for me, though. I knew from my youth that the transmission in the Morris was rather weak. I tore it up more than once. With the modest amount of power in my electric motor, there was no reason to have a transmission in an electric car like this anyway, so I went direct drive and never looked back. Plus, the old transmission and the new electric motor I used were about the same size, which made it easy for me to mount the motor in its place.

To mount the motor, I made a crossmember for the front of the new motor and used the original crossmember from the transmission. I attached the new motor to each of them with a pair of L brackets, adding rubber bushings to insulate the motor from vibrations coming through the frame. After those few simple steps, we were golden.

When I started on the Morris, I bought 48 new lithium-ion prismatic battery cells at 3.2 volts and 200 amp hours per cell, which worked out to 30.720 kilowatt-hours at 144 volts nominal. That cost me around $15,000, but I eventually replaced them with batteries from a crashed Model S at a junkyard where I paid $7,000 for seven packs. The cost of batteries scales linearly with their capacity, so you can spend almost whatever you want here.

A battery-management system isn’t strictly necessary, but it does a few things that make owning and operating your homemade EV a bit easier. The system monitors the individual cell voltage in the battery pack and ensures that they’re all functioning at precisely the same voltage, which you want for optimal performance. More importantly to me, because I’m a programmer by trade, it provides a ton of information about the car’s performance. Many people won’t care about these figures, but as a programmer I want to know everything.

ricketts an engineer checks the data from his battery management system

Ricketts, an engineer, checks the data from his battery-management system. You can buy a less sophisticated system to save money if you don’t want as much information. 

Ian Allen
a dc to dc converter pulls a charge from the batteries to power the car’s radio and other electrical systems eliminating the standard 12 volt car battery

A DC-to-DC converter pulls a charge from the batteries to power the car’s radio and other electrical systems, eliminating the standard 12-volt car battery. Not even a Tesla does that. 

Ian Allen

My system, which cost about $1,200, tells me the amount of current used, temperatures inside the battery pack, and other neat data. And it connects to an Android-powered head unit in my car, so I can view it just like I would on one of those big Tesla infotainment screens. There’s also an onboard AC/DC converter that you’ll need to install to allow for charging the batteries.

Most commercial electric cars include a 12-volt battery to power things like the radio and power-window motors, but since I designed this system myself, I could do something different. I added a DC-to-DC converter that takes power from the main high-voltage battery and converts it to 12 volts DC. I have it configured so that the converter runs 24/7. It draws a tiny bit of power out of the main battery pack as it does so, but it eliminates the need for a separate 12-volt battery. A Tesla can’t do that yet, but Elon Musk has talked about trying it. I also added an inertia switch, which de-energizes the battery if you get in a significant crash.

One nice thing about electric cars is that it really doesn’t matter where everything goes, aside from the motor. You can run the cables and wires wherever you need to, so I installed the battery-management system, the motor controller, and the DC-to-DC converter up in the engine bay at the front of the car. There was plenty of room in there to make everything look good, and also to make it easy to swap out or upgrade components later on.

Because I was restoring the body as well as converting it to an EV, I had the electrical components up and running before the body panels went on, so I was able to drive it around as an empty shell, which was amusing. This is effectively a body-on-frame vehicle, so there isn’t much of an upper structure to it. I installed batteries where the now-unnecessary fuel tank was and where the spare tire would have been carried.

I kept the brakes just the way they were—I press the pedal and it squeezes the calipers. I didn’t mess around with connecting them to the motor to increase regenerative braking, the way some EVs do. Instead, I can adjust regen directly through the motor controller. That makes it more like motor braking, slowing the driveshaft when I let off the gas. I only run that at 60 percent capacity, though. Anything higher than that, and I’d be awfully close to locking up the rear wheels when I let up on the throttle. So I have something close to one-pedal driving, and the standard brakes are there too.

Morris Minors have rack-and-pinion steering and are easy to drive without power assist, so I didn’t need to mess with anything there in terms of the original design. For conversions that require power steering, you can add electric pumps. You also can get electric air-conditioning pumps, if you wish. (I added AC to my electric pickup—another EV conversion I’m working on—for about $800 in parts.)

Even with the fancy modern propulsion system, I wanted to keep a traditional look and feel to everything. The mechanical linkage on the original gas pedal is joined to a potentiometer that’s in turn connected to the motor controller. A traditional speedometer would have connected from the transmission, but I had removed that. Rather than mess with trying to hook it up to the motor controller, I dropped in a GPS-based analog speedometer cluster designed for an old Jeep, which made life a whole lot easier. There are even options to link your original speedometer to a GPS controller, if you really want to keep things authentic.

The new speedometer also has an analog fuel gauge, which I wired up to the battery-management system. It sends a zero-to-5V output to the fuel gauge based on the battery’s charge. That’s what most people care about, so when it reads full, the battery is charged. When it’s empty, it’s empty. Simple! I don’t have my temperature display hooked to anything, but you could use it to monitor battery or motor temperature if you wanted to.

analog fuel gauge that ricketts connected to the battery management system

The speedometer cluster was made to fit some older Jeeps, but it slid into the Morris almost perfectly. It uses GPS signals to calculate speed, making it easier to install than a hardwired system. There’s even an analog fuel gauge that Ricketts connected to the battery-management system.

Ian Allen

I kept the original “W” and “L” knobs for the windshield wiper and headlights, and the original key acts as a simple on-off switch that turns on the motor controller.

I removed the original choke knob and the “S” pull-cable for the starter solenoid. I replaced those with the kind of forward/reverse switch often seen on golf carts, along with a single chrome button that can change modes on the motor controller. In the end, I used all four original holes in the dash for the various controls, because I hate drilling new holes and I really hate leaving holes unused.

I mounted the charging port where the gas cap used to be, and it’s capable of Level 2 charging, which runs on a 240-volt circuit at my home. The battery-management system supervises charging in case something goes wrong, but the onboard battery charger handles most of it.

At night, I plug the car in. My wall charger is programmed to start up after 10 p.m. to save on pricey California electricity. The Morris charges as needed and is ready to go in the morning. If I were to drain the pack completely, it would take about 14 hours to charge. Charging speed on a Level 2 residential charger depends on the vehicle’s internal capabilities. (The 2.5-kilowatt unit I used cost about $600.) If you want to fill up faster at home, you can opt for a fancier one capable of 6.6 kilowatt-hour speeds, for example.

It’s difficult for me to stop tinkering with my builds, even after they’re operable. I’m still upgrading the Morris. I replaced my 12V DC-to-DC converter because the original one would occasionally turn off for a brief period and the electronics didn’t like that. And eventually I changed the driveshaft for one with a center carrier bearing to get wobble and vibration out of the driveline, which worked like a treat.

electric charging port

Later, I replaced the AC-51 induction motor (and motor controller, because they come as a set) with a larger, more efficient permanent-magnet one. That was interesting—I got more power, more torque, and 30 to 40 percent more range. The upgraded motor was almost exactly the same size, so I just pulled one out and plugged the other in. Easy.

There’s a wrecking yard near me that specializes in Teslas. They really know their stuff, and they’ll walk you through the yard, and you can pull parts out of crashed Teslas. Thanks to this yard, I eventually upgraded the Morris to Tesla batteries, which saved me 300 pounds and improved my total battery capacity.

The Morris now has 120 horsepower, 175 lb-ft of torque, and 147 eMPG, or around 275 to 300 watt-hours per mile—that’s pretty similar in efficiency to a Tesla Model 3, although my little truck weighs about half as much. I’ve never driven it more than 90 miles because I just don’t go that far, but its range is around 125 miles. I use my Morris every day. So far I’ve put 18,000 miles on it.

My other vehicle is a Ram 2500, so with fuel prices where they are, guess which one I’m going to drive?


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