ELECTRIC VEHICLE TECHNOLOGY David Brandt, P.E.

The Basics: EV: electric vehicle Are EVs practical? Golf courses and airports have thought so for many years. But what about on the road? Are there EVs among us? Yes, and not just in California! Is there actually technology available to you and me to allow us to operate a practical EV? Yes!

OEM EVs (you may have heard of some of these): GM EV1

OEM EVs: Solectria Force

OEM EVs Corbin Sparrow PTV

Hobbyists? The hobbyist says If I cant buy one, Ill build my own… Honda Civic

More Hobbyist EVs My Escort

More hobbyist EVs Ford Ranger

Components What is out there that you need to have to build an EV (besides batteries)? –Motor –Controller –Charger –DC/DC Converter –Heater –Instrumentation –Contactor(s) –Safety Equipment

Motors OEMs: typically AC drive –Fail-safe design –Low initial torque, higher at speed –requires complicated electronics package AC speed control (similar to industrial) Inverter (convert DC to AC) High voltage ( VDC) Bearings only mechanical maintenance item

Motors Hobbyist: typically brushed DC series wound –Motors are available and inexpensive –100% torque at 0 RPM –Controllers are dirt cheap compared to AC –No inverter stage required –Lower voltage system ( VDC) –Bearings and brushes are potential maintenance items (change brushes every 100,000 hours or so)

Motors Advanced DC 9 diameter motor Others include GE, Prestolite

Controllers In General, Volts = Speed, Amps = Torque –Curtis to 144 VDC, 500 Amps –Auburn Scientific to 192 VDC, 1200 Amps –DCP to 336 VDC, 600/1200 Amps –EVCL GODZILLA to 336 VDC, 1200 Amps

Controllers All use PWM technology.

Chargers OEM: uses weird connectors like inductive paddle or AVCON gas pump nozzle. Hobbyist: How about something everyone already has, like 120 VAC household outlets and 240 VAC dryer outlets? Simple (voltage regulated) to complicated (computer controlled charging algorithms) More advanced charging required for advanced batteries (AGM)

DC/DC Converters Uses PWM to step traction pack voltage down to 12V to run car accessories. Common in electronics use Not widely available in the voltages required

Heater Ceramic - Self-regulating temperature of about 180° F. As temp. increases, resistance increases, decreasing power and stabilizing temp. Therefore, more air across the element = more heat. Typically 1500W. Can be stacked for more heat.

Heater The right type can be harvested from an AC ceramic heater.

Instrumentation Instrumentation can be as simple as an expanded scale voltmeter, but can be sophisticated, and include: –Traction Pack Voltmeter –Battery Current Ammeter –Motor Current Ammeter –Amp-hour/kWh meter (E-Meter)

Contactors BIG relays for switching traction pack

Safety Inertia switch to deactivate contactor(s) –same as is used to shut off fuel pumps in ICE cars AGM batteries - no spillage Service disconnects - BIG circuit breakers Fuses, of course Traction pack is electrically isolated from frame 8 G crash load rating recommended for battery boxes

Performance Acceleration and speed –About the same as ICE –Ranges from economy car to muscle car. –DC motors great for drag racing –Current NEDRA record seconds in the 1/4 mile by Current Eliminator

Performance tZero by AC Propulsion

Performance - tZero AC Propulsion's tzero out-accelerated a Ferrari F355, a new Corvette, and a Porsche Carrera 4 in a series of impromptu 1/8 mile drag races held on January 22, 2000 at Moffett Field in Mountain View, California, and at Calstart's northern facility at the former Alameda Naval Air Station.

Performance - tZero tZero mfg. By AC Propulsion versus Corvette

Performance Range - typically miles –somewhat dependent on if you have a lead foot –great for commuting, which is where people use the most gas anyway. –Use an ice vehicle for long trips - the right tool for the right job. Over 100 miles attainable with purpose- built EVs or using advanced batteries

Performance John Waylands 120 mile range Red Beastie

Performance Red Beasties battery pack

Emissions Common claim is EVs just move the pollution Point taken, but power plant emissions are scrubbed to a point not possible on a vehicle.

Emissions Belfast electric bus project (4 year duration of monitoring)