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November 2008
The Las Vegas Electric Vehicle Association (LVEVA) will meet on the third Saturday of each month during 2008. Meetings will be held at the Clark County Library on 1401 E. Flamingo Road from 10:15 AM to 12:15 PM. Members will be displaying their own electric cars and answering questions before and after the meeting.
Calendar
November 15 Monthly Meeting
December 6 Boulder City Christmas Parade
December 20 Monthly Meeting
2009
January 17 Monthly Meeting
February 14 Monthly Meeting
March 14 Monthly Meeting
LVEVA Board of Directors:
Richard Furniss, President
Lloyd Reece, Vice President
Bill Kuehl, Secretary/Treasurer
Al Sawyer, Jan Himber , Al D’Inzillo, Stan Hanel
Newsletter Editors and Contributors:
Richard Furniss, Lloyd Reece, Bill Kuehl, Al Sawyer, P.E.,
Jan Himber, Brent Singleton, Kent Singleton, Stan Hanel
WATTS HAPPENING
is published monthly by the
Las Vegas Electric Vehicle Association,
a chapter of the Electric Auto Association
Las Vegas Electric Vehicle Association web site
http://www.lveva.org
Electric Auto Association web site
http://www.eaaev.org
Electric Auto Association
Membership Renewals
323 Los Altos Drive
Aptos, CA 95003-5248
Current EVents contact:
At http://www.eaaev.org/eaaboard.html
Ron Freund
Chairman, CE Publication
Address Correspondence to:
LVEVA
2816 W. El Campo Grande Avenue
No. Las Vegas, NV 89031
Call for Information:
Richard Furniss (702) 453-6196
Jan Himber for Al Sawyer (702) 642-4000
Bill Kuehl (702) 636-0304 Stan Hanel (702) 405-0506
Contents:
-- Bill Kuehl’s “Saga of An EV Wannabe” (Part 5)
-- Bill Kuehl Wins Inaugural LVEVA Poker Run Road Rally on October 18th
-- LVEVA to Participate in Santa’s Electric Night Parade at Boulder City on December 6th
-- Killacycle Electric Motorcycle Sets New NEDRA ¼-Mile Drag Race Record on October 23rd.
-- Ausra, Inc. Completes First Solar Thermal Power Plant in Bakersfield, California
-- EV Motors and Motor Speed Controllers
-- Nominations for LVEVA Board of Directors at November 2008 Meeting
-- LVEVA DVD Reference Library
-- EV Repairs and Service
-- EV Conversion and Fabrication Support
-- EVs and EV Parts for Sale
The Saga of an EV Wannabe (Part 5)
By Bill Kuehl, LVEVA Secretary/Treasurer
Editor’s Note (Synopsis): This month continues the fifth of a nine-part series of practical EV conversion and driving tips written by LVEVA Secretary/Treasurer Bill Kuehl, who is also a co-founder and former president of the Las Vegas Electric Vehicle Association. The series recounts some of his thirty years of experiences as part of a small group of pioneers who believed they could convert gasoline vehicles into roadworthy electric battery-powered vehicles. This series of articles was originally published in the LVEVA “Watts Happening” monthly newsletters during 2003. With the recent rise of gasoline prices during the last few months, Bill’s story of his lifelong commitment to enabling EV conversions continues to hold many insights and helpful hints for the “do-it-yourself” EV builder. Bill Kuehl has converted over 200 gasoline vehicles to electric vehicles during the last forty years. He also holds records for ¼-mile electric vehicle drag racing and electric vehicle endurance racing.
During the first four installments of this series, Bill talked about the OPEC oil crisis that restricted the foreign supply of oil and petroleum during October 1973 as being the motivation for his interest in building electric vehicles. The cost of gasoline jumped from 33 cents per gallon to over $1.50 per gallon during a period of just a few months. Bill’s first attempts to make a full-size electric car for commuting to his work site that would cover a round trip of 16 miles resulted in a successful conversion of a 1974 Ford Pinto on a shoestring budget. This successful commuting solution worked for 3 ½ years until Bill’s work site was relocated, forcing him to redesign a vehicle that would have a round trip range of 32 miles. The second part of the series profiled a 1973 Honda Civic conversion that allowed him a range of over 60 miles on a single battery charge as well as allowing him to set an endurance record at a road rally sponsored by the Electric Auto Association that achieved 100.8 miles on a single charge of his lead-acid battery pack.
During the third part of the series, Bill talked about his acquisition of an Electric Pickup Truck, an electric Datsun 310 conversion, spare motors and controllers that were built by Lectra Motors in Las Vegas. He continued to participate in annual EAA rallies in Sunnyvale, California where he met like-minded EV enthusiasts from California who bought many of the parts and the Datsun 310. Bill also detailed his successful EV conversion of a 1985 Pontiac Fiero and his electric auto cross racing experiences with the Sports Car Club of America that included fellow LVEVA members Jan Himber and Al Sawyer at the Las Vegas Motor Speedway.
Bill Kuehl’s saga of EV conversion, experimentation and discovery continues…
Since converting my 1985 Pontiac Fiero in 1991, I continued to perform a series of upgrades to it. I was not too happy with the performance of the battery pack at 96 volts, so I added four more batteries to increase it to a 120-volt system. I had originally installed a Curtis 1221B motor speed controller but found out during the following summer that the very hot Las Vegas temperatures (above 110 degrees Farenheit!) caused it to go into thermal cutback mode when stopping at a stop sign after driving just a short distance. I replaced the Curtis Controller with an older Cableform controller during the hot summer months that used less efficient SCR-based technology but did not overheat. This final arrangement worked well for me during the next few years. Every September, I would continue to tow my electric vehicle up to Sunnyvale, California, to run in the National EAA rally that was held there.
In April of 1994, there was a Clean Air Road Rally held in Los Angeles from April 9th to April 12th. I towed my Pontiac Fiero to L.A. to participate in the that rally, as well. Friday, the first day of the event, was used for registration and “scrutineering” at the Los Angeles Convention Center. After checking in and getting my car registered, I joined each of the other electric vehicle owners to go through a safety inspection. This inspection included a check of all systems on the car – lights, turn signals, seat belts, windshield wipers, tires, windows, horn, batteries, wiring, brakes, circuit breakers, battery charger and extension cords.
Then the cars were run through an Acceleration Test and a Brake Effectiveness Test, with points awarded for each.
Points were also given for three aspects of the rally competition and these points were used to evaluate the final winners. The first goal of competition was to arrive in the “perfect” course time established for the posted speed limits, traffic control signs, traffic lights, etc. The second was a timed acceleration run, which determined the order in which the vehicles would leave on the competition run the next day. Additional points would also be awarded on Day Two and Day Three for endurance runs consisting of supplemental laps, different road courses, and completion of each route. There were 54 electric vehicles participating in the rally.
Day Two (Saturday): All the cars were lined up according to the times they posted during the acceleration run. Slowest cars went first. Start time was 10 AM and each car left at ten second intervals. A map had been furnished to each driver and we had to follow the streets that were marked on the map up to a “halfway point” (usually a large store parking lot) where we had to wait for 10 minutes before proceeding onto the second half of the run.
It was 7.6 miles to the halfway point. After waiting my 10 minutes, I continued on the second half of my run. My Pontiac Fiero was running well until I went up a small hill and had to stop at a traffic light. When the light turned green, I stepped on the accelerator pedal but there was little power to move the car. The Curtis 1221B Controller had gone into thermal cutback mode. As luck would have it, I was at the top of the hill and the roadway was headed downhill. I went through the intersection slowly and, as the car picked up speed, there was more air flow over the controller that dissipated enough heat to allow the controller to come out of thermal cutback mode. I continued driving with my eye on the amp-meter to keep current flow as low as possible in order to keep the controller from heating up again. I also looked down the road at oncoming traffic lights to try to gauge their time so that I could keep moving at a steady pace and avoid losing air flow over the controller.
This driving technique helped me finish the second leg of the course, completing 23.7 miles to the finish line at the Santa Monica Pier. I did four additional laps on the supplemental course for a total of 63.7 miles.
Battery charging was supplied from a portable Electric Vehicle Fueling Station. This charging station was provided by Dan Parmley, who owned Diversified Technical Services in Phoenix, Arizona. The station was 8 feet wide by 20 feet long by 8 feet high and could be connected to 60 EV battery packs that could all be recharged during the same time. The Electric Vehicle Fueling Station was parked on the beach just north of the Santa Monica Pier where there were plenty of adjacent parking spaces for all the electric vehicles to plug in and recharge their battery packs from 7 PM to 7 AM the next day.
After hooking up my car to the charging station, I left the area to stay at my son’s place to eat and get a good night’s sleep. However, soon after I got through eating, I received a phone call to come back to the charging area because my charging circuit had tripped its breaker and my battery pack was not receiving a charge. Upon arriving back at the beach, I found that my extension cord had overheated and burned out, overloading the circuit breaker. One of the other EV’ers had a power cord that he let me borrow but I had to change the plugs on it to fit the ones on the charging station. It was about 2 AM before I got my car to start charging again and I had to be back at 7 AM for the next day’s run. The batteries did not get a full charge.
Day Three (Sunday): I participated in a driver’s meeting at 8 AM and checked the routes on the map for this day’s run. Cars began leaving at 9 AM at 10-second intervals to travel from the Santa Monica Pier to a halfway point located 17.1 miles away. I reached the halfway point and stayed at that location for the 10-minute waiting period but, after driving about five miles into the second leg of the course, I notice a lag in acceleration due to the batteries not receiving a full charge the night before. I had to accelerate very slowly and lightly, but was still able to drive the rest of the 28 miles to the Queen Mary exhibit in Long Beach for a total of 42.8 miles. My point standing after the rally put me in 25th place in the original field of 54 vehicles. Upon arriving at Disneyland in Anaheim and getting checked in at the finish, all the race participants were given admission passes to the Disneyland theme park. We left our electric vehicles grouped together in the parking lot for the public to look at. It was a really good rally. During those four days, thousands of people had the chance to observe electric vehicles up close and see that they can be driven on city and suburban streets just like any other car but without polluting the air.
Editor’s note: End of Part Five. “The Saga of an EV Wannabe (Part Six)” will continue in the December 2008 issue of the LVEVA “Watts Happening” newsletter, and will chronicle more of Bill Kuehl’s pioneering EV conversion projects and racing adventures. Happy Clean Air Motoring!
Bill Kuehl Wins Inaugural LVEVA Poker Run Road Rally on October 18th
The first inaugural LVEVA Poker Run Road Rally on October 18th brought together a field of five electric and hybrid gas/electric vehicles to compete for the “Electric Man” EV trophy (affectionately named “Herbie” by trophy designer and builder Al Sawyer). The racing teams included Lloyd Reece driving his Lectra Centauri battery-powered electric car, Jon Hallquist driving a converted Volkswagen Vanagon electric van, Al Sawyer and Jan Himber driving a 2005 Toyota Prius hybrid gasoline/electric car, Bill Kuehl driving 2004 Toyota Prius hybrid gasoline/electric car, and Richard Furniss driving a 2002 Toyota Prius gasoline/electric hybrid car.
During the monthly October LVEVA meeting at the Flamingo public library, contestants were given a map of the four-mile course that wound through the nearby streets of Las Vegas between the starting point at the library parking lot on Flamingo and South Maryland Parkway, then east on Flamingo Road to waypoints at the Blueberry Hill restaurant and TGI Friday’s restaurant, returning northwest to Orr Jr. High School parking lot and then heading west to the finishing line at Carl’s Jr. restaurant located at Desert Inn and South Maryland Parkway.
The race started at the Flamingo public library where each driver drew a playing card from a single poker deck. At each of the other four waypoints along the route, the driver of the EV or hybrid car would pick another playing card from the same poker deck. Dan Trujillo and Richard Furniss shared duties as the dealer for the single deck of cards, transporting it to the five locations. The competing race teams followed the designated route on the map while obeying all traffic rules and speed limits. At the finish line in the Carls’ Jr. restaurant parking lot, the driver from each team then received their last playing card and compared their poker hands to determine the winner of the LVEVA Poker Run Road Rally. The results of the five-card draw were as follows:
1. Bill Kuehl Straight (7, 8, 9, 10 and Jack)
2. Jon Hallquist Pair of Aces (Ace and Joker Wild Card)
3. Al Sawyer/Jan Himber Pair of Kings
4. Lloyd Reece Pair of Jacks
5. Richard Furniss Pair of Deuces
Bill Kuehl is the winner of the “Electric Man” EV trophy from the very first staging of the LVEVA Poker Run Rally on October 18, 2008. The LVEVA hopes to continue to hold this event every October, expanding the distance of the race as well as the number of electric vehicles competing. “A good time was had by all” -- so much, that plans are underway to inaugurate a second annual road rally next Spring 2009 that will include a scavenger hunt along the route.
LVEVA to Participate in Santa’s Electric Night Parade at Boulder City on December 6th
Boulder City will be staging its annual Santa’s Electric Night Parade on Saturday evening, December 6th, from 4:30 PM to 6 PM. According to Boulder City’s Events web page, “Santa will arrive in Boulder City with a spectacular parade! All entries are lit and include lots of enthusiastic participants. This hometown event is a great way to start your holiday festivities.” For more information, visit the Boulder City web site at: http://www.bcnv.org
All LVEVA members are invited to attend to participate in the parade segment featuring the LVEVA and its members’ electric vehicles. The LVEVA hopes to provide a full spectrum of Electric Vehicles to ride on or ride in during the parade, from Electric Bicycles and Electric Scooters to Neighborhood Electric Vehicles (NEVs) to full-size electric cars and trucks.
For the last ten years, LVEVA members have enjoyed decorating their cars with Christmas lights and props during this annual EVent as well as spreading the message about alternative electric transportation options. For directions and more information, please contact LVEVA officer Richard Furniss or Bill Kuehl at their phone numbers shown on the front pages of this newsletter.
Killacycle Electric Motorcycle Sets New NEDRA ¼-Mile Drag Race Record
Editor’s Note: From Killacycle Owner Bill Dube at: http://www.killacycle.com
October 24, 2008
The KillaCycle, ridden by Scotty Pollacheck, made drag racing history AGAIN at Bandimere Speedway October 23rd, 2008. 7.89 seconds @ 168 MPH is a new official NEDRA record and makes KillaCycle the world’s quickest electric vehicle of any kind in the quarter mile! This was the very last run down the strip for this season at Bandimere. What a great way to finish the year.
Lightning struck twice on the mountain as we set the new mark for top speed in an earlier run that afternoon, 7.955 seconds@ 174.05 MPH. The M&H Racemaster tire really gripped the awesome track prep provided by Larry Crispe and the crew at Bandimere Speedway. We turned up the launch current to 1850 amps per motor, well beyond what we ever had before, and still did not slip the tire! (The all new temperature-controlled track surface provided the very best possible traction.)
Jim Husted at Hi-Torque Electric did his magic to the motors and they were able to withstand more RPM, current, and voltage from the battery pack than we thought was even possible. This is what delivered the “back half” performance that made the new top speed record possible.
The A123 Systems NanoPosphate batteries are changing the entire landscape for electric vehicles, and battery-powered devices in general.
The History Channel recorded it all that day. The footage will air early in 2009, perhaps February or March.
A YouTube video of the record setting run is available at: http://www.youtube.com/watch?v=PVv0NVLFPig
Editor’s Note: More information is also available from the National Electric Drag Racing Association (NEDRA) web site at: http://www.nedra.com
See the “Record Holders” web page for current rankings at: http://www.nedra.com/record_holders.html
Ausra Completes First Solar Thermal Power Plant in Bakersfield, California
During October, Ausra, Inc. unveiled its first Kimberlina 5-Megawatt Solar Thermal Power Plant that can provide electrical power to about 3,500 residential homes in Bakersfield, California. This company’s first installation in the U.S. is also the first new concetrated solar thermal power plant built in California during the last 20 years. The successful installation will be the first step in proving the technology can be scalable. A second installation is now underway in San Luis Obispo County that will produce a 177-Megawatt solar thermal plant with the same technology, providing power to over 120,000 residential homes.
Ausra Inc., a developer of utility-scale solar thermal power plants, recently also built its first U.S. manufacturing plant for solar thermal power systems in Las Vegas and started production here in April 2008. The 130,000-square-foot, highly automated manufacturing and distribution center will produce the reflectors, towers, absorber tubes, and other key components for the company's solar thermal power plants. It is located near McCarran International Airport near the junction of Highways 215 and I-15 at 6405 Ensworth Street. This year, the manufacturing plant is currently employing 25 people locally and is hoping to expand to 50 employees in the next two years as the solar power industry continues to grow.
John O'Donnell, Ausra's executive vice president of manufacturing, said the plant is heavily automated and relies on multiple robots to manufacture the parts and pieces needed to construct a solar power plant, similar to the way automobiles are assembled and welded. By automating the purchasing, warehousing, production and distribution processes of solar components in larger volume, the company hopes to drive down the cost of its solar components so that they will be more competitive with coal production costs for coal-powered electrical plants.
Before choosing Las Vegas as its manufacturing site, Ausra Inc. had considered the San Francisco Bay Area, the city of Barstow on the California side of the Mojave desert, and Phoenix, Arizona. O'Donnell credited Nevada's "business-friendly climate"; U.S. Sen. Harry Reid's push to make the state a center of renewable energy; and its location in the heart of the "solar Southwest" as reasons for selecting it as the home for its plant. Las Vegas summers surpassing 110-degree Farenheit temperatures will provide valuable “real world” test data for the manufacturing and development team.
"We are proud that Ausra has chosen southern Nevada to build its U.S. manufacturing plant, bringing economic growth and new jobs to our state," said Somer Hollingsworth, president and CEO of the Nevada Development Authority (NDA). "The business-friendly environment we enjoy here provides Ausra and other companies a wealth of benefits. Ausra's decision to locate here points to Nevada becoming a leader in building and delivering clean power to our state, to our region, and to our country. Clean energy is growing our economy and helping America secure our energy future."
"We chose to locate in Nevada because it is the center of America's solar energy future. Nevada has massive solar resources, available land and a growing demand for clean energy, with huge markets next door in California and neighboring states projected to demand many thousands of megawatts over the coming years. Nevada's business-friendly climate, excellent transportation and workforce resources, and large-scale need for clean power made it the obvious choice," said Rob Morgan, Ausra executive vice president and chief development officer.
Once manufactured and tested here in Las Vegas, and then proven at the new Bakersfield power plant, these systems will then be shipped to San Luis Obispo County to a site near the town of California Valley. The planned 177-Megawatt solar thermal array project will cover over one square mile of land in this isolated area in rural California. As a reference, 1 megawatt of power can supply the needs of 750 homes: http://ausra.com/news/releases/071105.html
The company’s aggressive goals are to make enough reflectors, towers, tubes and other solar components to create solar collectors capable of generating 700 megawatts of power within the year following the opening of the plant. This would be the equivalent of manufacturing systems that could cover four square miles of land each year. These are lofty goals and would surpass the total production capacity of the entire solar industry at this time, hopefully selling these components to new solar generating plants in California and other neighboring states. California has set a state government goal focused on obtaining 17 Gigawatts (17,000 Megawatts) of additional renewable energy, including solar power, by 2020.
Solar thermal power plants use fields of mirrors to capture the sun's power to produce electricity without pollution. Ausra's innovations in mirror systems have brought the price of solar power down to the cost level of gas-fired power plants today, and will soon reach prices associated with coal-fired power generation. Solar thermal power plants can store energy as heat to continue power generation at night and during cloudy periods.
Ausra's Compact Linear Fresnel Reflector (CLFR) solar technology utilizes the heat from the sun's rays to create steam. Solar collectors boil water at high temperature to power steam turbine generators, in much the same way as traditional fossil-fuel power plants. However, a solar-based fuel source is renewable and does not produce carbon-based emissions when generating power.
About Ausra
Ausra, Inc. develops and deploys utility-scale solar thermal power technology to serve global electricity needs in a dependable, market-competitive, environmentally responsible manner. Located in Palo Alto, Calif., Ausra is a privately held company funded by Khosla Ventures and Kleiner, Perkins, Caufield & Byers. To learn more about Ausra and solar thermal power in general, visit www.ausra.com.
In September 2007, Ausra received a $40 million investment from two influential Venture Capital companies-- Khosla Ventures and Kleiner Perkins Caufield & Byers. Former U.S. Vice-President Al Gore recently joined the Board of Directors for Kleiner, Perkins, Caufield & Byers.
The company has also announced its intention to construct a second plant in conjunction with Florida Power & Light. It is likely that Ausra will build a manufacturing facility in the Southeast to serve that project. Company goals are to provide 17 GigaWatts of power to different regions throughout the U.S. and worldwide by 2020, equivalent to the state goal set by California. California started with an initial push to achieve 20% of its energy from renewable resources by 2010. Nevada’s state initiatives for renewable energy begun in 1997, 2001 and 2003, are hoping to achieve 20% of its energy from renewable resources by 2015 with a much smaller population than California.
Electric Vehicle DC Motors and Motor Speed Controllers
by Stan Hanel
When comparing the performance of an electric motor that can power a roadworthy electric vehicle at the same level as a gasoline engine, a car designer really needs to look at the internal design of an electric motor and its related power system to examine the performance and range that can be achieved to accommodate all kinds of driving conditions and road terrains.
Electric Vehicle Motor Components
To start with, a DC-powered electric motor should really be thought of as a motor/generator. In general, most DC motors have two components that make them work, the stator that sets up a stationary magnetic field and the rotor or “rotational” part of the motor that reacts to the magnetic field of the stator. An electro-mechanical rotor is called an armature. The most common stators in a DC motor are made of either permanent rare magnets or wound electric coils. Because of the high cost of permanent magnet materials for larger motors, the most common rotor or armature configuration in an EV-scale DC motor is one with formed coils that are series-wound in the stator and use a “brushed commutator” to drive the rotor/armature.
The armature is composed of an insulated series of copper bars, or poles, attached to electro-magnetic coil windings. Electric current is fed to opposite sides of the armature assembly by stationary spring-loaded brushes that are pushed against the copper contact bars. The brushes pass electrical current to the armature bars and attached electromagnetic coils but also allow the copper bars of the armature to rotate under the stationary brushes as it turns. The armature can turn in either direction depending on the polarity of the electrical current that is applied to the bars through the brushed commutator.
As the armature coils are energized by electrical current from the brushes in one direction, each coil becomes an electromagnet that reacts to the electromagnetic field produced in the stator coil windings. This reaction induces rotational movement in the rotor/armature with high amounts of torque. To reverse the direction of rotation, reverse the polarity of the current applied by the brushed commutator to the armature bars and associated electromagnetic coils.
In a DC motor/generator, the converse is also true. As the rotor mechanically spins inside the magnetic field of an energized stator in one direction or the other, the two electromagnetic fields can actually create electrical current flow. While driving an EV, a sensitive motorist can feel this reverse flow of voltage and current from a free-spinning motor that is being mechanically turned by its coasting wheels and mechanical drive train. At this point, the motor’s coils are acting as two inductors that are producing impedance in the form of reverse “Electro Motive Force” or “back EMF”. Back EMF actually pushes back against the voltage and current supplied by the electrochemical battery pack and motor speed controller, impeding the electrical current flow.
This dynamic “yin and yang” between the battery voltage and current applied to the motor as well as the “back EMF” that the motor/generator is able to produce and feed back on its own, make for a different set of driving skills that are necessary to coax the best performance and range out of an electric vehicle. Inductive reactance is defined as the dynamic resistance or impedance that ebbs and flows during the motion of the motor in reaction to voltage or current changes within these inductors. There are converse relationships between the ebb and flow of electrical current and the strength of the magnetic fields in the coils that react to each other. These reactances are actually dynamic impedances that can either resist or enhance the performance and range of an electric vehicle when harnessed appropriately by the driver.
EV Motor Speed Controllers
Modern EV DC motor speed controllers from manufacturers like Curtis PMC, Café Electric, Logisystems, Alltrax, and other companies all use Pulse Width Modulation (PWM) to “ramp up” the speed of the motor by generating a square wave pulse with varying duty cycle widths for the voltage “on” part of the square wave. By applying varying widths of positive-going voltage pulses to the “gate” pins on a bank of power transistors, a much larger current flow of at least 400 Amps or more can be switched from the battery pack to the motor through the controller. Many controllers invert the positive-going input PWM signal to the transistors at the output of the controller, so that the full battery current from the output of the power transistors is chopping the negative cycle of the modulating output square wave that drives the motor. By using PWM, the motor speed controller allows for in-between “off” times of the applied current, that leave room for “back EMF” to return from the motor through the controller to the battery pack.
PWM signal pulse widths to the input gates of the power transistors are shaped by a potentiometer or hall-effect sensor mounted in the accelerator pedal assembly that connects to the front end of the motor speed controller. As the accelerator pedal is pushed gradually to the floor by the driver, ever-widening output pulses of large current from the bank of transistors can more efficiently overcome the inertia of a stationary vehicle as well as vary the speed of the motor with fine control, even under heavy loads like a steep hill. By contrast, pushing the accelerator pedal all the way to the floor on an EV and applying a “fully on” DC voltage to the transistor bank may gate full current to the motor quickly. However, this driving behavior will actually consume more of the battery capacity available and will coax less performance from the electric motor compared to backing the pedal off to a 90% “pulse on” that allows some return flow of “back EMF” and actually increases “flow through” of the electric current to the motor to increase the system’s efficiency.
Motor Speed Controller Evolution
Sophisticated motor speed controller electronics continue to evolve with the growth of the power semiconductor industry. Originally, large contact strips were manually switched to create increasing steps of battery current flow, limited by large resistive coils. Acceleration was accomplished by manually shifting through these electrical current flow steps in the same way as a gear shift, but by choosing the appropriate amount of total current that was fed straight through different portions of a large resistive coil. However, because the full current from the battery source was being attenuated by the components, this system also dissipated heat and energy along the circuit path from the battery through the coil, contactors, cables and motors. This would shorten the overall range of the power system because of losses through the electrical components.
Silicon-Controlled Rectifiers (SCR) were the first hardy semiconductor devices introduced into motor speed controllers that could handle a lot of battery current flow. A rectifier or diode is normally a cylindrical-shaped device with a wire on either end that allows current to flow in one direction but not the other. However, Silicon-Controlled Rectifiers had a third connection point that could provide a “gate” to the current flow from the battery pack to the motor through a parallel array of these devices that could all be turned on at the same time. Not as much power was dissipated through the semiconductor “switches” as had been consumed using mechanical methods. The DC current flow to the motor could be turned on and off at the “gate” of the device in a more linear fashion by using a much smaller resistor element in the accelerator pedal assembly. The result was a major conservation of battery energy that normally would be dissipated as heat during operation, increasing the overall range of the battery pack during each charge/discharge cycle. The one flaw in the design of SCR-based controllers was that, when the devices would fail, power would keep flowing through the controller and could not be turned off. Some EV manufacturers, like Lectra Motors in Las Vegas during the 1980s, had to install a red “panic button” kill switch on the dashboard of their production vehicles that would disable all battery power to the system if the controller failed this way during operation. However, SCRs continue to operate very well in high temperature environments and are superior to other semiconductor technologies in this respect. During the late 1980s, improvements in the design of a Field Effect Transistor (FET) exhibited enough robustness, power and speed to be adapted for use in EV and golf cart motor controllers. Many of these FETs can be wired in parallel so that they can be turned on or off as one system, depending on the control signal applied to the “gate” of the FETs. As these FETs became more rugged and durable with each new generation of semiconductor technology, they became more capable of handling larger voltage and current loads from the battery pack to the motor.
All EV-scale motor speed controllers need to be capable of handling large transient current flows of 400 amps or greater in both directions without damaging the internal electronics of the controller. Power transistor banks in modern controllers are usually populated by more rugged Field Effect Transistors (FET) or Insulated Gate Bipolar Transistors (IGBT). Power FET controllers can handle 400 to 1200 amps of current flow from battery packs rated up to about 300 Volts DC. Larger voltage and current requirements for EV systems are better handled by Insulated Gate Bipolar Transistor (IGBT) technology, such as the Zilla motor speed controller from Café Electric that is rated over 2000 amps at 400 Volts DC and above. IGBTs combine the best features of both FETs and Bipolar semiconductor transistors because they are voltage controlled like FETs but have very fast switching speeds, like bipolar transistors. Both FETs and IGBTs are activated by applying a certain voltage level to the gate of each device that switches a much larger current flow from the battery through each transistor in parallel to the motor. Fast recovery diodes inside a motor speed controller help channel the “back EMF” and high-amperage transient currents from the collapsing magnetic fields of the electric motor back to the battery pack. Lead-acid battery packs can usually absorb these large current back flows without damage to the battery pack’s internal chemistry. Newer, advanced Lithium-ion battery technologies may need additional capacitors or other transient current protection components to keep the individual battery cells in the pack from exceeding their maximum operating capacities.
EV Driving Tips
Once an electric motor starts spinning at its optimal operating speed (say 5,000 rpm), it assumes a mechanical hysteresis quality that allows it to spin with the assistance of just a small amount of voltage and current flow. When coming to a stop sign, the rotor/armature does not slow down immediately as a driver takes the foot off the accelerator pedal, compared to the way an internal combustion engine behaves. In a gasoline engine, the piston compression and friction create much more drag on the overall drive train when the spark plugs are not directly igniting the incoming gasoline. This causes the vehicle to slow down more quickly and even stall the engine if the transmission clutch is not pushed in to disconnect the motor drive train from the transmission and wheels as the engine comes to a stop but must continue idling.
An electric motor, however, has a tendency to continue spinning more freely. It does not have stall problems because the electric motor does not idle while stopped, only consuming battery power when the accelerator pedal is engaged and the motor starts to turn. To slow down, an electric motor relies on the mechanical rolling resistance of the tires, terrain, internal drive train, internal motor friction, wind resistance and the vehicle’s four brake shoes. EV drivers should be prepared to take their foot off the accelerator sooner when coming to a stoplight and spend more time coasting up to the stop with the transmission fully engaged. The free spinning electric motor will slow down gradually but still continue to drive the car as it spins, even up a hill. The mechanical design of an EV tries to minimize internal and external mechanical resistance as much as possible. Some EV owners even drain the thick 90-weight oil out of the differential gear box and replace it with a lighter synthetic oil for smoother performance and less drag on the differential gear assembly.
It is always a good idea not to step in the clutch until the electric motor slows down, as it is initially spinning at a high rate of speed and may accelerate even more if it is released from the wheels of the vehicle too quickly. Depending on the specifications of the motor, this might create “over-rotation” of the electric motor rotor/armature, loosening the armature bars from their mountings in the process. Proper EV driving leaves the electric motor in gear all the way to the stopping point. After stopping, the EV driver can then down shift to a lower gear ratio without using the clutch because the electric motor is not spinning at this point and consuming any energy. This practice can save “wear and tear” on the clutch materials, prolonging the life of this important transmission component. A synchromesh manual transmission is preferred for this type of gear shifting where the electric motor can be mounted on the vehicle drive train by creating a custom adapter plate and coupling. The electric motor will mount in a much smaller area than the original engine to the clutch assembly. Custom adapter plates for more common EV conversions can sometimes be purchased from EV parts dealers. Otherwise, a good machine shop can fabricate an aluminum adapter plate and coupling that will join the transmission and clutch to the electric motor.
Some motor/controller packages can be equipped with regenerative braking systems that will slow the motor down electro-mechanically and also convert the braking energy into electricity that can then be fed back in to the batteries to recharge them slightly. This adds more mechanical drag to the overall drive train and may cut overall range on level ground but may be somewhat safer. The motor speed controller that is equipped for regenerative braking also has more complex electronic circuitry and will be more expensive. Depending on the surrounding terrain, a regenerative braking system can recoup about 5% of normal battery pack capacity during daily usage if the EV is going down a lot of hills or braking frequently to stop during city driving.
By contrast, a heavy-footed driver who leans on the accelerator pedal all the time can drain the resources of a battery pack quickly if that driver is constantly applying too much battery power against the forces of “back EMF” and inductive reactance. A more experienced EV driver will work with the different properties of the electric motor and “go with the flow” of the interplay between applied battery power and back EMF to increase the performance and range of his EV. A light, steady foot is much more effective in EV driving. Giving the electric motor/generator just the right amount of current it needs from the battery pack to nudge it into the “sweet spot” on its rpm/torque curve is the “art of EV driving”. It makes every road trip interesting, challenging and exciting. The enjoyment is identical to the way a rally car driver would look at his terrain and constantly adjust the performance of his vehicle to maximize time and range from one destination point to another.
EV Motor Performance Optimization
The rpm/torque curve diagram for each motor is one good specification for comparing DC motors and their suitability for an EV environment. An rpm/torque curve datasheet is usually available from each EV motor from its manufacturer as part of a motor’s technical specifications and may be downloadable from the manufacturer or accompanying distributors’ web sites. The relationship between the “revolutions per minute” (speed) of an electric motor and its rotational force (torque) is not linear. Torque in an electromagnetic motor is created with the application of enough voltage and current to generate strong, opposing magnetic fields that force the motor to begin rotating. With the right design, this system can be very powerful when the motor is just starting to rotate (i.e. 0 rpm to 2500 rpm). However, once the vehicle is moving and accelerating, the torque in an EV motor should then taper off to a flat, constant level in order to conserve battery current requirements as the motor reaches its cruising speed (i.e. 3,000 rpm to 5,000 rpm). For example, if an X-Y graph is used to picture this relationship with TORQUE on the Y-axis and RPM on the X-axis, the curve will climb steeply initially but start to taper and flatten out at about 2,500 rpm.
At its “sweet spot”, the motor is also in a very efficient electromechanical mode that requires very little battery power to sustain it on level ground, just enough to overcome rolling resistance, wind resistance and the vehicle’s internal mechanical drive train resistance. The rpm/torque curve can be optimized for an EV environment that requires a balance between its street-level performance and range by considering the design of the stator and the rotor inside the motor.
Basic DC motor systems for electric vehicles continue to evolve and we hope to highlight more of these different technologies and features in upcoming newsletters, as well as the many new variations on both DC and AC propulsion systems. As shown in this article, each motor variation must also be complemented by compatible electronics and mechanical drive train integration.
Nominations for LVEVA Board of Directors at November 2008 Meeting
During the monthly Las Vegas Electric Vehicle Association meeting on Saturday, November 15th, from 10 AM to 12 noon, registered members of the LVEVA whose dues payments are current can nominate candidates for at least two rotating Board of Directors positions that will become open this year. There are seven elected members on the LVEVA Board of Directors who commit to serve three-year terms as governors of the local Las Vegas chapter. Elections for the positions on the Board of Directors are staggered each year so that at least two terms expire each December to allow for a new vote.
Each candidate who is nominated during the November 15th meeting must be seconded by at least one other registered and fully-paid member of the LVEVA. All nominated candidates will then be selected by secret ballot during the next LVEVA monthly meeting on December 20th. As before, only registered and fully paid members of the LVEVA will be eligible to vote in the December election. The candidates with the most votes will become the new members of the LVEVA Board of Directors. This new Board of Directors will then meet after the LVEVA monthly meeting on January 17th to appoint officers and discuss proposed agendas for 2009.
Please attend the November and December LVEVA monthly meetings to insure that your voice and ideas are heard, as well as help us determine the future direction of the LVEVA and its leadership. Thank you for your continued support of the Las Vegas Electric Vehicle Association.
LVEVA DVD Reference Library
The LVEVA maintains a growing library of DVD reference videos that are available to its members that can be borrowed for one month at a time. Bill Kuehl, LVEVA Secretary/Treasurer is also the LVEVA video librarian. He can be contacted to pick up and return these videos at each monthly chapter meeting. The current list of videos that are available for a one month rental are:
1. “Who Killed the Elecric Car” Documentary
2. Plug in Partners National Campaign (2006)
3. EAA Silicon Valley CalCars PHEV Technology Overview (2005)
4. Boulder City Christmas Parade Highlights (2006)
5. Convert Your Pickup to Electric (DIY Video by GrassrootsEV)
Note: This video can be copied to viewer’s hard disk to keep!
6. Tom Gage of AC Propulsion speaks at EAA Silicon Valley (2005)
7. Monster Garage EV conversion (Jesse James)
and John Wayland White Zombie Videos (2006)
8. Electric Avenue by George Gladic Fox Valley EAA Chapter 2006.
9. Bruce Katz of Polyplus Battery Company speaks at EAASV (2005)
EV Repairs and Service
Western Petroleum Station
2051 E. Sahara (corner of Eastern Avenue and Sahara)
Las Vegas, NV 89104
Contact: Jim Johnson
Telephone: (702) 457-2675
Web site: http://storefront.dexonline.com/jims-texaco
EV Conversion and Fabrication Support
Rock Monster Motorsports
5225 S. Valley View Blvd.
Las Vegas, NV 89118
Web site: http://www.rockmonstermotorsports.com
Tel: (702) 255-2700
Fax: (702) 255-2710
Contact: John
EV Precision Machine Shop Custom Parts Fabrication
Accurate Machine and Tool
3855 W. Diablo, Suite #6
Las Vegas, NV 89118
Tel: (702) 739-0939
Contact: Eric Tschabold
Email: energyz@cox.net
EV Parts and Kits for Sale:
GrassrootsEV.com
Las Vegas Office
Address: 5225 S. Valley View Blvd., Las Vegas, NV 89118
“Electric Vehicles and Everything for Them”
Contact: Jon Hallquist
Tel: (702) 277-7544
Email: jon@grassrootsev.com
Web site: http://www.grassrootsev.com
OKA NEV ZEV Parts and Kits for Sale: www.okaauto.com
OKA NEV ZEV KIT cars in stock now for immediate delivery prices start at $5,000 FOB Las Vegas. We also have 4844 ALLTRAX Controllers(48V 400 A DC for Series motor) in stock (more than we need) $550 list, $375.00 NET.
Contact: Miro Kefurt
OKA AUTO USA : www.okaauto.com
Distributor: MIROX Corporation
5015 W. Sahara Ave. #125-130
Las Vegas, Nevada 89146
USA
Tel: (702) 683-8292
E-mail: okaauto@aol.com
The Free Energy Store
300 West Utah, Suite 101
Las Vegas, NV 89102
Tel: (702) 320-0770
Fax: (702) 320-0270
Web site: http://www.freeenergystore.com
Contact: Russ Lord
Email: russ@freeenergystore.com
For Sale: Chrome "Electric" Emblems for EV's
Mike Chancey - Posted 06/25/00
Location: Kansas City, Missouri
Checked: 07/13/03
Chrome "Electric" car emblems, just like the OEM factory lettering. Okay, so you own a beautiful electric vehicle, but does the world know? Show them with these profession quality "ELECTRIC" emblems. Fabricated from weather resistant thermoplastic, these signs feature a bright chrome like finish on the letter faces with a subtle matte black background. They mount easily with the self adhesive HighTack backing. Simply peel off the protective cover, and press the sign into place. Each sign is approximately 1.25" in height and 7" in length. Only $6.00 each or four for $20.00, plus $1.75 shipping and handling per order. Discounts for larger orders available. Send check or money order to:
Mike Chancey, 1700 East 80th Street, Kansas City, MO 64131, or order online.
EVs For Sale:
Electrans 3-wheel Futurista ETV
Range of 55 miles
Top speed of 45 mph.
Department of Transportation (DOT) approval to license this vehicle through the DMV
List price is $13,995
Contact: ElecTrans
Address: 3928 San Andreas, Las Vegas, NV 89121
Tel: (702) 927-8838
Web site: www.futurista.biz
For Sale: Electric 1985 Pontiac “Fiero” --Record-Holding Race Car
This 1985 Pontiac “Fiero” Conversion currently holds four National Electric Drag Racing Association (NEDRA) Class Records.
1. Class MC/F (Modified Conversion 97-120 volts)
2. Class MC/E (Modified Conversion 121-144 volts)
3. Class MC/D (Modified Conversion 145-168 volts)
4. Class MC/C (Modified Conversion 169-192 volts)
The 1985 Pontiac Fiero has been converted with:
1. A new Netgain Warp-9 Electric DC Motor coupled to a 5-speed manual transmission.
2. A DCP T-REX 1000 Water-cooled Controller with an Input Voltage Range of 96 to 336 Volts
and Motor Current Rating at 1000 Amps.
3. The Battery System is at 192 Volts. The battery pack consists of sixteen 12-volt sealed ODYSSEY PC-680 batteries with the capability of increasing battery pack capacity and voltages to compete in the NEDRA MC/B Class (Modified Conversion 193-240 volts) or to a maximum capacity of 336-volts to compete in the MC/A Class (Modified Conversion 241 volts and higher).
4. Tires are B.F. Goodrich G-Force T/A Drag Radials P215/60 R14 that connect the Electric Motor torque to the road for “no slip” acceleration.
5. Battery Charger is a 120- to 240-volt Variable Transformer with a heavy-duty full bridge rectifier. Additional cables and connectors are installed for Dump Charging from a DC battery pack.
Asking Price: $10,000 or Best Offer.
Contact: William Kuehl
Address: 4504 W. Alexander Road, North Las Vegas, Nevada 89032
Telephone: 702-636-0304
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