The Platform
This 2003 BMW 325i was chosen for the conversion.
The Project
This project leverages off the known properties and traits of the classic BMW 325 series sports car without compromising anything. In many ways it gets better.
The vehicle was purchased and it's performance was measured with 5 runs at Portland International Raceway drag strip on Aug 17, 2007. Major EV components were selected and the conversion officially began on Sept 1, 2007 when the gas engine was pulled.
This design does not rely on future technology. It is comprised of current production high performance EV components. The one element that has been missing from the performance electric market until recently: the battery.
Robust, high current cells that have the necessary power/weight ratio are now available. These batteries are less hazardous than the common Lithium Ion cells since they do not contain oxides.
A good portion of the total effort for this project is the design and construction of the 15kWhr power pack using a new generation of Lithium Ion cells from A123 systems. This is the secret sauce that makes this project possible.
Motor choice is an AC induction type manufactured by Siemens of Germany. This brushless motor, it's control and charging system all share the original water cooling system.
The motor is wound specifically for 700 Volt operation (rather than the more common 350 Volt) to extend the full torque level 2 times further up in RPM. This requires battery cells that can deliver both high electrical current and voltage without being overweight.
The weight and the weight distribution is maintained after the conversion. The interior and trunk space will not be affected. Heating and air conditioning will also work in the same way except... the heat will be almost instantaneous because there is no motor to warm up and the air conditioner runs independently with it's own variable speed electric motor, both of which get their power from the high voltage battery pack.
The manual transmission will be used to allow setting the gear reduction ratio for selecting the desired torque applied to the rear wheels. Normally, it will be left in 2nd or 3rd gear that will handle the normal zero to highway speed range. On the track, 4th gear may be needed which may also be appropriate for longer trips on the freeway. First gear will now require a limited slip differential to help reduce spinning the tires off the line and on the inside wheel of a turn. Although I am keeping the manual clutch, with this electric drive system, the clutch will not be needed for starting or stoping! You just let off the brake and press on the "go" pedal. It will occasionally be used for shifting while in motion.
The charging is as simple as plugging in an extension cord. The length of time needed to charge a fully discharged pack is 4.5 hours when plugged into a 240VAC outlet fused similarly to a dryer outlet. The standard 120VAC outlet will also work but will be limited in power so will take longer. At current electricity rates, my 40 mile daily commute will cost $0.60 @ 6 cents/kWhr.
The Benefits
Not only will the car be fast and fun to drive, this concept also happens to be part of the solution to significantly reduce our use of fossil fuels. This is not just an increment in fuel mileage improvement, but ELIMINATION of the need for fuel within a 50 mile* range!
When power is taken from the electrical grid to charge this EV, the cost is 6 times less than the cost of gas needed to drive the same car the same distance at $3.00/gallon. This difference will grow larger without question in the near future. Get ready, the price of crude has nearly doubled in the last year.
The emission profile is significantly reduced, especially here in the Pacific NW where we have very little power generated from coal, coming instead from hydroelectric sources. We purchase renewable sourced power so none of it comes from any carbon emitting sources.
Phase 2 of project: With a modest solar array, approx 16x16 feet, mounted on the south facing roof of the house, the net cost to drive 40 miles daily will be $0 on clear days. With a power inverter directly connecting the solar array to the electrical grid, the power meter spins backwards during daylight hours. When you come home, you just plug into the AC outlet and take back the power you generated during the day. This is beneficial to the power grid by helping reduce the peak load during the day as a side benefit. You can size the solar array to match the power used in your normal daily drive.
Now, to reconsider the emission profile with the solar array just mentioned above, there are no emissions. None. Not even battery cells venting at any time. Rarely even leaving brake pad dust behind.
Regenerative braking. This drive system has the ability, and the battery system has the performance to capture 80% of the braking energy. The original brakes are still there but used less often. This makes city driving particularly efficient since the wind load is low and there is a lot of brake use required which returns more power back.
No engine noise. If you can't imagine not having the rumble and revving of an internal combustion engine(ICE), think electronic amplifier driving a good sound system with whatever type engine sound you download; model T, '69 small block Z28, ferrari etc. Silence is a now a choice.
There is only one moving part in the motor: the rotor spinning on bearings. The service and maintenance drops significantly. The most significant service needed: Tires.
Having this high performance actually improves the efficiency of the “grocery getting” driving. Here is the reason: When a power source is designed for and capable of delivering large currents, the losses are significantly reduced when lightly loaded.
Unlike a gasoline engine, this electric drive system doesn't sacrifice mileage for performance.
The battery cells are non-toxic and completely recyclable after more than a decade of use, where the Lithium is recovered. This means less to extract from the mines.
*Phase 3 of project: A small aerodynamic trailer pod will house an efficient generator able to power the car at highway speeds without battery use. This will give the best of both worlds; unlimited range and/or pure electric. Greater than 90% of the driving is done within the 50 mile range so the pod will sit at home most the time. When a storm knocks out power to the house, there will be a generator available to power the complete electrical load as a side benefit.
