This section of my new site is mostly done at this point, but I will likely still be refining and adding information over time.
This is the main page for my 2004 Scion xB EV (electric vehicle) conversion. The Scion replaces my old 1985 Toyota MR2 EV conversion, which I completed in 2007 and drove for 6 years as my primary around-town car until the scion came online in June 2013.
For EV Conversion concepts and terminology, look at the EV Terminology.
For nauseating detail on the build, jump straight to the Construction page.
- Solectria AC55 motor with UMOC445F Inverter
- 320V, 100AH, 32kwh lithium battery using 100 GBS lithium manganese prismatic cells.
- Manzanita Micro PFC-30 charger
- J1772 inlet and adapter module allows use of L2 public charging stations.
- Elithion Pro BMS
- 4.8:1 overall ratio direct drive via synchronous belt system and 1984 Toyota celica GTS differential and custom CV shafts.
- 1.5kw electric heater
- 3040lbs curb weight
- 100hp with 175ft-lb motor torque from 0-3000rpm;
- Regenerative braking
- 80mph design top speed
- 4800 motor RPM at 60mph.
- 0-60 15s (estimate)
- 250wh/mile battery to wheels under most driving conditions; 100 mile useful range.
While my 1985 Toyota MR2 EV was very successful, my wants and needs in a car have been changing. In addition I now have a bit more budget available than I did when I built the MR2. I wanted a car that would:
- Seat 4
- Tow a small trailer
- Have sufficient driving range to reach my parent’s home 80 miles away even under less than perfect driving conditions, e.g. rain, wind, cold.
- Have room for a reasonable amount of cargo even with a passenger or two.
- Be capable of using public charging infrastructure.
While I knew pretty early on I was going to select the scion xB for my next conversion, I did do my usual research and compared a variety of similar vehicles. My research validated what I already suspected which was the xB was well suited to EV conversion as it was substantially lighter than any of these other similar cars and despite being pretty boxy it was nearly the best aerodynamically as well. Its only real down side was not a whole lot of room for batteries as so much of the car is interior space. The vehicles I considered included the Scion xB, Chrysler PT cruiser, Pontiac Aztek, Honda element, Mazda 5, and Chevrolet HHR. Of course there are other similar cars like the 2nd generation xB, the Nissan Cube and the Kia Soul, but most of these were too new and thus too expensive, or I simply did not like them.
I bought the xB in June 2012 from a sleazy used car salesman who was selling cars on the street in Portland. He had bought the car from a chain smoker named Fred but had not transferred the title. Anyway I paid cash for the car and after airing up the tires, checking fluids and a couple other minor fixes I drove it home from Portland to Seattle without incident.
Condition as Bought
My perfect xB was one that was white or green, had lowered suspension, and had a decent body and interior but high mileage or mechanical problems and thus would be cheap. The one I ended up buying was about right in terms of mileage and body condition, and it is one of my desired colors and had lowered suspension.
The major downside to the one I bought was that it had been owned by a chain smoker, and the interior was very, very, soiled with nicotine funk. The first thing I did upon getting the car home was tear out and steam clean the entire interior of the car.
On the positive side, this is one of the few cars I have bought that was actually able to drive home under its own power.
It took about 800 hours (estimated) and just about a year calendar time to complete this project to the point of being drivable. The project included many phases, which are outlined briefly and roughly chronologically below. For (much) more detail on the conversion process, visit the Construction page.
- Remove ICE Components: Engine, Transaxle, gas tank, exhaust system, ECU, engine compartment wiring harness and clean engine compartment.
- Manual Steering Swap: Replace the original power steering rack with a manual rack to simplify the build and improve efficiency.
- Drive Train: Design a sub frame to hold motor, differential, inverter, and other engine compartment components in position and join them together using synchronous belt and custom CV shafts to get power from the motor to the wheels.
- Battery Boxes: Locate, remove sheet metal from rear floor of the car, design and build 3 battery boxes: a) “Mid” box under rear seat, “Lower” box under rear floor, “Upper” box behind rear seat.
- Cable Conduit and Breaker: Install high voltage conduit and high voltage DC breaker between the battery boxes and engine compartment.
- Electric Heater Core: I am in cool, wet (9 months of the year, anyway) Seattle. A working heater/defrost is necessary.
- Vacuum Brake System: The original braking system of the scion is largely unchanged, but a new source of vacuum must be provided to power the brake booster.
- Rear Suspension Upgrade: Heavier springs must replace the original TRD lowering springs, which would not carry the extra weight of 600lbs of battery. Minor modifications to the rear axle beam spring hangers were also needed to increase clearance to the battery boxes.
- Inverter Installation: This involved physically mounting the Solectria UMOC445TF inverter and routing cables to the passenger compartment and motor, and building a moderately complex interface board to allow the UMOC inverter to communicate with the driver (gas pedal, forward/reverse, indicator lights, etc) as well as communicate with the BMS and original systems of the car.
- DC/DC Converter: Rebuild, Locating, Installing the DC/DC converter, which replaces the alternator by stepping down high voltage from the traction battery to keep the 12V battery and automotive systems such as lights, wipers, etc. running.
- Battery Installation: Repackaging and installing the batteries, adding insulation.
- BMS Installation: Wiring, Interfaces
- Charger and J1772 Interface: Installing the Manzanita Micro PFC30 charger and mostly-homebuilt J1772 and BMS interface components.