The EV’s of “ThorMacEV” are aimed at the EV buyer who will not compromise comfort & speed for simply “being green”. Thor Johnson realizes EV’s are not likely to enjoy great market penetration if they are limited to the stereotypical econo box look and performance. Here we’ll take a look at Thor’s Porsche Boxster EV conversion.
Name, Age, Location ?
Thor Johnson, 35, Atlanta, GA
Primary occupation ?
Electrical Engineer / CTO
Its not necessarily just the green aspect you’re interested in with electric cars is it?
Yes, I like the idea of being able to choose the power source for my car (and not be locked into oil from the middle east), but the existing “green” cars were too much to stomach:
1. NEV – Limited to 30 MPH, and usually only have 30 mile range…. I live in Lawrenceville (NE Atlanta) and work in Kennesaw (NW Atlanta). With a NEV, I wouldn’t be able to even make it there, much less make it back. And limiting the speed to 30 MPH would kill freeway operation so I couldn’t even run downtown to meet my friends in the city!
2. Prius Gen 1 – Still a gas-eater, and when running in electric mode, anemic. For much of my driving I’m not even sure it would do as well as a normal gasoline car since the majority of my mileage is highway driving.
Our stated motto is “Purveyors of Proper Electric Vehicles”; this means that the default goal in a conversion is to not change your relationship with your car:
B. It will have adequate daily range (our target with the Boxster is 100 miles)
C. All systems will work (including power steering and air conditioning!)
We feel that if you have > 100 mile range, the idea of “having to stop for a recharge” falls by the wayside; at that rate, I can commute between Lawrenceville and Kennesaw, and even stop for drinks downtown without worry. For longer trips, this may not be the car for you (however, we have some R&D projects to aid with that!), but wouldn’t it be worth it to commute in a car that is not only green, but is also one that you love?
Is this conversion your first of its kind ?
This is the first Lithium conversion we’ve undertaken. Mac Quillian has done other conversions for the DOD at Warner Robins ALC. From this, we are creating plans for future Boxster conversions as well as finding ways to step-up the quality and performance of the conversions.
The next steps are to find like-minded individuals and propose custom conversions for them, keeping with the ThormacEV motto.
Why did you choose the Boxster as your starting point ?
We chose a Boxster because we deemed it a worthy car, and we loved the idea of a sporty convertible electric vehicle. For the range we desired, the amount spent on the conversion would be close to the same regardless of whether we started with a Corolla or a Boxster, so we chose the sexier, more sporty option.
The funny thing about range vs performance is that when you get to the amount of energy required to move the car 100 miles, the performance almost comes naturally. With our 400V, 32 KWh battery pack, we can draw 100-300A (40-120 KW) without too much strain on the batteries.
Our other concern is that the car be Proper; ie, the rest of the car works properly. The AC, power steering, convertible top, and spoiler all work on the car. We did not want to be stuck in Atlanta traffic sweating because the air conditioning was a “waste of energy.”
Where did you source the majority of the parts ?
Our components come from several places to get the best performance value that we could muster. As we innovate and design our own parts (for example, the accessory drive/transaxle mount that you see in the picture), we expect to sell our parts to others who want their conversions to “just work.” Our batteries are from EvComponents; they are Thundersky LiFePO4 cells.
During the conversion process how did you anticipate and deal with the possibility of added weight ?
The electric drivetrain adds only 300 lbs to the Boxster. We have made it a point to keep our conversion aligned with the spirit of the Boxster (low polar moment to enable quick handling, etc).
Tell me about your pack, controller and motor, why did you choose this combination ?
We chose a MES-DEA AC motor & Controller for performance, reliability, and size. Because the motor is water-cooled, it weights half of a Warp-13 DC motor or an air-cooled AC motor. We’ve chosen to retain the clutch and the transaxle to provide better performance (electric vehicles *like* short-shifting; to maintain performance on the high end, you still need to change gears) and keep the packaging simple.
Have you upgraded anything in regards to safety ?
Since we are not changing the weight significantly, we have not done much in the way of mechanical changes to the Boxster beyond making sure our changes do not adversely affect the Boxster’s existing safety mechnaismes (eg, we did not put batteries against the bumper!).
The electrical system uses double-insulated electrical cables, and the High Voltage Front End isolates the controller from the batteries when the power is off and checks the isolation as the system starts up. We also have a safety interlock that prevents the car from being powered up when the charger is connected.
What do you think the advantages of your car being electric are ? And, what are the disadvantages ?
The largest disadvantage is cost. If you want to go green, have fun, and do it in style, the ev-Boxster fits the bill well.
If you have a car that you love, but an engine you don’t (for example, I have a friend with a 1966 Mustang that has a cantankerous engine in it), talk to us, and we’ll find a way that you can keep what you like about that car (style, performance), and lose that engine.
Also… in Atlanta, you can drive in the HOV lane by yourself.
Where from here ?
More cars, better systems, and possibly working on some more custom projects. For the existing hybrid people, we are looking into PHEV and performance upgrades. For our clients, we have a number of ideas that improve the charging performance, range, and other “current limitations” in the research phase.
If you had the money what would be your next goal ?
It’s hard to choose from all the different research projects we have planned, but the first couple on the list would be a better charging system and a range extender so you could have your EV and have vacation range when needed. But I don’t want to leave out the existing hybrid owners….
What or who was your inspiration ?
Which are some of your favorite conversions or available new EVs ?
The Tesla seems to be the best engineered car I’ve seen in a while. I really enjoy their blogs from an engineering standpoint. The scuttlebutt I’ve heard regarding the Nissan Leaf is also well-thought-out, but it remains to be seen whether or not it will make it to the dealerships.
What does the wife/husband/friends think of your car ?
They think it’s a cool car, but too expensive. As the price of batteries fall…
What has your conversion experience taught you ?
It’s always harder than it looks at first, and the best solution always seems to be more elegant. As our research projects continue, I learn more about these systems every day.
Thor Johnson and his EV’s can be found at thormacev.com