Joe Yanof’s 1989 Corolla EV
Joe Yanof, 29, Phoenix AZ
What is your primary occupation ?
I’m an engineer at Honeywell designing mechanical systems for jet engines that go in helicopters and business jets.
What got you interested in electric cars Joe ?
It started one of those summers when gas prices hit $3 a gallon (2007, i think). My buddy and I thought there had to be a better way, so we started researching electric cars. Preliminary research showed that going electric wouldn’t really be cost effective until gas was around 4-$5 a gallon, so we sidelined the idea. Then, the next summer, gas prices did hit $4.50 a gallon, and that’s when I really got interested and the conversion started.
Of course, gas prices plummeted after that, but I’ve since realized other benefits of going electric (clean, quiet, simple, reliable fuel source, car pool lane, etc)
Is this your first EV ?
Yes, unless you count a couple RC cars I had when I was a kid.
Actually, I’ve used 3. They are all rated at 500A / 144V.
The first was a Kelly 500A 144v controller. I was attracted to the lower price, but was misled by the ratings. The controller pushed 500A for the first few seconds of a drive, but after that, it self-limited to about 350A. My motor is a little undersized for the weight of the vehicle and it required a higher power controller.
I then upgraded to a Curtis controller. This was that odd time in the hobby EV world where there were no controllers available. Everything was either out of production or out of stock or having field problems. I was able to find a Curtis 1231c at a dealer and swapped it for the Kelly. Even though it has the same ratings, it was able to sustain the output required to accelerate reasonably (just need a few seconds of high current to get rolling). However, once the weather warmed up, the Curtiswould trip into over-temp mode and cut back power more often. Often, this happened at in-opportune situations, like making a left turn, or accelerating onto the highway.
I knew that the Curtis was an old design and that there must be something out there that’s better. I had the good fortune of stumbling upon the open source controller project that Paul Holmes had started. I liked the idea of a controller that is simple enough to build yourself that also performed really well. He had just begun building his second prototype and was looking for volunteers to beta-test the controller. With the hottest months of summer just ahead, I volunteered with the added benefit of testing the controller in one of the harshest environments. We had some development issues, mostly tweaking software here and there, but it has since performed beautifully for 7000 miles and counting. It runs a lot cooler than the curtis and thus performs better in the heat. It’s completely silent, at all speeds. It has many configurable options, such as battery amp limit, throttle response controls, motor over-speed sensing. It’s also nice to be familiar with the design so that troubleshooting any problems that come up is easier.
(Paul’s website is here http://paulandsabrinasevstuff.com/)
24 lead acid batteries is a lot to fit into a coupe, how did you achieve this ?
The initial plan was to get as many under the hood as possible and then fit the rest in the trunk. The only thing that really had a predefined location was the motor, so I planned to stuff batteries wherever I could and put the rest of the components in the space available.
I made a cardboard replica of the battery case to trial fit them and ended up finding room for 7 under the hood (4 in the radiator/condenser area and 3 above the motor). This worked out well since the weight on the front wheels ended up about the same as before (no need to modify springs). I initially planned to put 13 in the trunk, but once I got started, realized there was room for 4 more.
I think these older vehicles had a lot of room under the hood and in the trunk, and may have skimped on passenger compartment volume. Nevertheless, there’s very little room for anything else besides batteries, and it’s really heavy!
Which battery did you use ?
Did the battery boxes and fitting the batteries take lots of planning ?
The planning wasn’t too hard or time consuming. Fabrication took forever! Probably more than half the time converting the car was spent on fabricating the battery racks. Of course, with batteries stuck in every nook and cranny, a lot of fabrication was required.
Did you aim to get as large a pack into as light a car as possible ?
This was my original intent. They say that of the three characteristics (range, performance, low cost), a conversion can have two of them. My long commute is 52 mi round trip and I didn’t have a ton of money to play with, so I chose range and cost. Additionally, I knew that range would decrease in colder weather and get worse as the batteries aged.
So, I figured a small aerodynamic vehicle filled with batteries would best achieve my range goal throughout the life of the pack. Of course, performance suffers, meaning acceleration and cornering are awful.
Living in Phoenix, you implemented an A/C system, where did you source the parts?
The a/c system was unfortunately an afterthought. I didn’t intend to use a/c, but I must’ve been in la-la-land and somehow thought I could survive these summers. There wasn’t any room for a separate motor / automotive compressor nor was there room to drive a compressor off the tail shaft. I ended up using a compressor from the smallest window hvac unit i could find. It’s from a 5k BTU zenith unit, i think. The system uses the condenser that came with the unit, but I had to fabricate some of the copper tubing (from Ace) that connects it. The long hose runs from the trunk to the firewall were made at a local a/c shop. They also helped charge the system and test it out.
What’s nice about these scroll compressors is that they’re small and efficient. However, they run on AC power, not DC, so I needed an inverter. There are 12VDC to 120VAC inverters, but I thought it’d be silly to convert high voltage from the battery pack to low voltage and then back to high voltage. So I did some research and built my own sinewave inverter that runs straight from the battery pack.
Unfortunately, 5k BTU isn’t quite enough for great a/c. I get about 20-25F drop in temperature from the vents relative to the outside temp. It’s fine when it’s 100F outside, but not so great when it’s 115! I think 10k BTU would be better.
Lastly, since everything is electric (and not connected to the drive train), the a/c is easy to turn on and off by activating a few relays. I found a radio controlled relay on ebay for $25 that has a 100m range. It’s hooked up to activate all the required relays for the a/c and I now have a remote start for the air conditioning!
Does using the A/C affect range noticeably ?
The a/c uses about 3-4 battery amps at 150v, which is about 3-4% of the amount of power required to move the car down the highway at 55 mph. This is hardly noticeable. Another way to look at it: If I left the a/c running for an hour, i’d use up about 1.5 miles’ worth of range. But, of course this would be worse if I had a higher capacity a/c compressor.
How often do you water your batteries ?
About once a month or so, a little less in the winter.
Where did you buy your adaptor plate and coupler from ?
The adapter plate is made from a 16″ round piece of scrap aluminum. A friend of mine has a 4-axis CNC milling machine. I made some measurements and drew it up as a simple CAD sketch and he made it for the cost of the cutting bits.
The coupler was a challenge. I had the female spline for the input shaft from the original clutch plate and a sprocket that I found on a surplus site that had the correct hub bore and keyway slot for the motor. I just needed a way to connect the two.
I ended up grinding off the teeth of the sprocket so it was just a cylinder. I found another piece of steel cylinder at the metal store that was the same diameter as the hub to act as a spacer between the hub and spline. Another friend has a lathe and was able to cut the parts as required so they piloted well and fit together nicely. He also welded them together and it came out very well balanced.
All in all, the adapter plate and coupler were inexpensive, but I was fortunate enough to be able to use some scrap metal and have some friends who are capable machinists.
What do you think the most critical part of the build was ?
For me, it mostly likely centered around getting the motor in place. All of the component placement under the hood was based around the motor location, and the number of batteries in the trunk was based on how many I could get under the hood. On top of that, proper alignment of the motor and transmission shafts is critical and potentially a lot of work to redo if something didn’t fit correctly.
Which EV enthusiast sites do you visit ?
I receive the EVDL and EVTech lists, and often visit DIYelectriccar and EcoModder.
I’m intrigued by the Leaf – it seems very promising and I hope it’s a success. The Volt is a good gateway eCar. Maybe people purchase it and realize they only occasionally need the ICE engine. Meanwhile, maybe battery technology improves or becomes cheaper, and more people realize that a pure EV (with perhaps a bit more range) would suit their lifestyle.
I haven’t seen other conversions, but I admire people who can find parts and put together a suitable vehicle for very little cash. I’m also amazed at the technology and performance achieved at the other end of the spectrum.
What do your friends think of the car ?
They all think it’s pretty cool and ask about it a lot. My engineer friends get a kick out of it, for sure. I haven’t yet convinced anyone to convert their own vehicle, though.
What has your conversion experience taught you overall ?
A ton. I didn’t know much about cars, welding, controllers, motors, batteries, etc… It seems each aspect of the conversion has it’s own little area of available expert knowledge – battery maintenance, crimping cables, best practice for wiring, and the list keeps going. What’s fantastic is that much of this information is available on the web and there are a bunch of helpful people on the discussion forums. Also, jumping on board with Paul Holmes and his DIY controller initiatedme into the world of electronics. That’s been a lot of fun and I’ve got quite a few small electronics projects now.
What was your conversion cost including donor ?
donor – $300 on craigslist with a blown motor.
motor – $1700
controller – $400 or so
charger – $750
batteries – $2500
adapter plate – $250
coupler – $100
DCDC – $250
random other parts (new windshield, tires, steel for racks, wiring, gauges, etc) – $1500
So, maybe about $8k or so. Quite a bit more if you included things I spent money on, tried them out, and realized it didn’t work well (like the Curtis Controller).
Do you have a favorite story about building or driving your EV ?
The EV grin is pretty special, especially after months of work.
Otherwise there’s the carpool lane story: In Arizona, a vehicle that is registered with electricity as a fuel source gets an emissions waiver and a blue ‘alternative fuel’ license plate. The main benefit of the blue license plate is that you’re allowed to drive in the carpool lane. I don’t drive fast, but the carpool lane comes in handy when there’s traffic and the carpool lane is only going 45 mph anyway. I save a lot of time and coulombs by avoiding the stop and go.
There’s this one stack in the freeway system where the 202 joins I-10 westbound. I-10 comes around a 90degree bend and 202 has it’s own carpool lane offramp that joins the carpool lane of I-10… it’s the perfect place for a motorcycle cop to sit and catch carpool lane free-loaders who come around the bend or the dedicated offramp. So I’m in the carpool lane and see him up ahead after the bend in the shade of an underpass. His eyes follow my car as I, a lone passenger in a 22 year old vehicle driving in the carpool lane, approach his position. I know exactly what he’s thinking. I watch my mirrors as I pass by him and he whisks his bike around ready to chase me down. But, he doesn’t get 5 ft before abruptly stopping with a frustrated look – must’ve seen the plates!
Are there a few people you’d like to thank ?
Definitely Yates and Larry for helping with the coupler and adapter plate. Also, thanks to the guys at the Interstate Battery store in Mesa for helping with the pack and AZ Auto and Air in Tempe for all the help with the A/C system.
Is there anything else you’d like to mention ?
Once this battery pack starts to go, I do plan on upgrading to Lithium batteries. I hope to get another year or so from this pack, so hopefully by then Lithium comes down in price a bit and there’s more data on the best BMS scheme for them.
Starting off with lead has been great for learning without risking a ton of money, but the car is very heavy, slow off the line, uses a lot of power going up hills, and just covers my daily commute needs. A lithium pack of the same volume would reduce the weight of the vehicle by 25% and yet provide over 100 miles of range (at 55 mph) allowing for the random errand at lunch or trip to see my folks.
At that point, I wouldn’t need another car for my daily driving and could sell my Civic to cover some of the battery costs. We’d take my wife’s car if heading up north for the weekend or some other long trip. That’s the plan, at least.
While swapping battery packs, I’d also take the opportunity to re-do a few things in the car. This was almost a kind of proof-of-concept vehicle to convince myself that going EV is possible and affordable for my needs, so there are some things I’d do differently. For example, while the direct coupler is simplistic, I still have to shift quite a bit based on typical speed limits and gear ratios. so, I plan on re-installing the clutch.
I think I’ll also try to be a little more strategic with the battery placement in an effort to have some trunk space. I’ll look at putting batteries under the rear seat and where the spare tire compartment is. This will take some serious modification to the vehicle, but since lithiums should require significantly less maintenance than flooded lead acids, I could potentially install, forget, and have trunk space.
Along the battery train of thought, I’ll also try to enclose the battery boxes so that there aren’t any exposed terminals.
Then, since the spare tire space may be filled with batteries, I’ll move the A/C unit and condenser back to the front of the car. I’ll probably use the original vehicle’s condenser and look for a compressor that’s at least 10k BTU. My inverter should be able to handle the extra load of a larger compressor.
Are there any EVs out there who you’d like to see on EV Gearbox ?
Unfortunately, I haven’t seen any other conversions. You might be interested in talking to Paul Holmes though. He has a budget-converted VW bug (I think) and is knee deep in a lot of open source EV hardware development.
More photos of Joes conversion can be found here http://picasaweb.google.com/jyanof/EcarAlbum?feat=directlink# and his EV Album page here http://www.evalbum.com/2358
Thanks again Joe :)