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EV101: Owning and Operating an Electric Vehicle Gary Graunke Oregon Electric Vehicle Association (Oregon chapter of the Electric Auto Association) December,

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Presentation on theme: "EV101: Owning and Operating an Electric Vehicle Gary Graunke Oregon Electric Vehicle Association (Oregon chapter of the Electric Auto Association) December,"— Presentation transcript:

1 EV101: Owning and Operating an Electric Vehicle Gary Graunke Oregon Electric Vehicle Association (Oregon chapter of the Electric Auto Association) December, 2007

2 Gratefully acknowledging many slides from Steve Heckeroth Director of BIPV, ECD Ovonics Chair Renewable Fuels and Sustainable Transportation Division of the American Solar Energy Society

3 Agenda How electric cars work Maintenance on an electric car Costs of operation Uses for electric cars Sustainable transportation vs fossil fuels Questions and Answers

4 How Electric Cars Work Throttle variable resistor tells motor controller desired speed –Like radio volume control Motor controller varies pulse width to motor –Rapidly switches battery voltage on and off Contactors (relays) may be used to reverse motor –Other contactors used for safety disconnect Charger recharges batteries from grid DC-DC converter charges low voltage “starter” battery from high voltage pack Motor Differential Speed Pedal Motor Controller Traction Batteries Charger Contactors Aux. Battery DC-DC Just like a toy car, but high voltage and high current (danger!)

5 Throttle Linkage Zap Throttle LinkageConverted Honda Insight Linkage S10 Electric Pickup Linkage Mechanical Input Electric Output

6 Motor Controllers DC motor controllers pulse high voltage to motor –Pulse width controls speed –Relays used to reverse motor Some motor controllers do regenerative braking –Slows vehicle by generating electricity from motion –Recharges batteries Curtis 1231C (ZAP) CafeElectric Zilla 1K Contactors (ZAP) Electricity is the only alternative fuel you can create when you go downhill

7 Series Chargers Proper charging is important for battery life! Each battery has its own protocol –Initial bulk charge usually constant current (max power) –Finishing charge is constant voltage (power decreases) DeltaQ charger (ZAP) Brusa NLG512 chargerManzanita Micro PFC

8 DC-DC Converters Most EV’s have small 12V aux. battery –Runs lights, horn, etc –Runs motor controller logic—needed to start –Small: no engine to start! DC-DC charges aux battery from high voltage pack –Voltage change –Isolation (safety) Some are integrated with motor controller Zap DC-DC

9 Agenda How electric cars work Maintenance on an electric car Costs of operation Uses for electric cars Sustainable transportation vs fossil fuels Questions and Answers

10 EV Maintenance Tires and brakes are the same as gas cars –Regenerative braking reduces brake wear No filters, mufflers, oil changes, engine valves, rings, pollution control, fuel pumps Care and feeding of (lead acid) battery pack –Ideally charge when 50% and 70% left –Avoid discharge < 20% state of charge Leaving discharged causes sulfation in lead batteries –Keep lead-acid batteries topped up Batteries self-discharge (charge periodically if not in use) –Avoid overcharging (good chargers won’t do this) Running batteries down and letting them sit discharged is very bad for them

11 Managing Safety Issues Service disconnects to break HV battery string into small parts –Voltages must be below 60V to be “safe” –High voltage, high current shorts can cause plasma fires –Maintain isolation of HV pack and chassis Need two connections to form circuit—don’t give up this advantage! Remove rings while working on battery pack –High currents can weld objects Batteries must be securely fastened down Use DC-rated fuses, switches, relays –DC ratings are typically 1/3 of AC ratings Flooded batteries may explode--wear eye protection Flooded batteries can spill H2SO4, KOH Overcharging (mostly flooded) may produce explosive H 2 Nevertheless, electricity has safety advantages –Does not leak into air and explode/catch fire –Easily stopped by fuse or switch anywhere in circuit

12 Proper Tools for Safety Electrical tape on metal sockets and other wrenches Rubber handle wrenches Rubber gloves –Certified if higher voltages Fiberglass shaft screwdrivers / nutdrivers Certified and isolated test equipment (meters and scopes)

13 Battery Balancing Relative cell state of charge varies over time –Manufacturing variance –Different operating temperature –Series charging increases differences in state of charge Individual chargers is one solution Stop driving when lowest cell is empty Stop charging when highest cell is full (5% overcharge ok) But charger and instruments measure total pack voltage –Ideally measure individual cell voltages –Measuring highest, lowest batteries is good approximation voltage full 2.16V empty 1.75V voltage full empty overcharge Periodic rebalancing improves battery pack longevity

14 Capacity Variance with Aging As batteries age capacity variances increase –More imbalance! Easier to overdrive –Weakest cell voltage plunges and may even reverse polarity! –Best case: shorter range Low temperatures also reduce effective capacity –Eventually it’s time for a new pack! Lowest capacity cell is also overcharged Active automatic battery balancers mitigate extremes voltage full empty overcharging voltage full 2.16 empty 1.75 Overdriving 0 volts Check aging pack batteries for varying capacity

15 Use Appropriate Batteries 12V batteries need sufficient power to stay above 10.5V (short bursts ok)

16 Past Time for a New Pack 2V differences indicate exhausted or reversed cells

17 Battery Management Add-ons Hart Batt-Bridge is an “idiot light” costing <$10 –LED lights when two halves of pack differ by > 2v –One cell empties/reverses first –Charge now or go “turtle mode”! PowerCheq modules –Keep each two adjacent batteries voltage difference <.1V –Works 24X7 while driving, charging, parked –Limited current—keeps balanced pack balanced –Requires N-1 modules for N batteries

18 More Battery Management Aids Manzanita Micro MK3 regulator prevents overcharge –Backs off charger when individual battery full –Limits battery voltage –Data logging Hart balancer relay module (30A capacity) –Scans batteries to measure voltage –Connects any battery to isolated “flying” battery or DC- DC –Can take charge from higher state-of-charge batteries –Gives charge to lower state-of- charge batteries

19 Agenda How electric cars work Maintenance on an electric car Costs of operation Uses for electric cars Sustainable transportation vs fossil fuels Questions and Answers

20 Costs of EV Operation Top EV cost is battery wear –3 to 15 cents / mile –Assumes proper care! Fuel cost 2-3 cents/mi –10 cents/KWH and 4-8 mi/KWH –1 US gal gas = 33 KWH S10: 66 mpg equivalent NEV: 245 mpg equivalent Electric motors last! –AC motors: 1 moving part –DC motors: brushes Top heat engine cost is maintenance –28 cents / mile (CARB) –Engine/drive train wear Currently 10 cents/mi –$3.00/gal and 30 mpg –Geologists, investment bankers say global oil production has peaked –Expect unlimited price increases EV owners replace batteries when heat engine owners replace vehicle

21 Agenda How electric cars work Maintenance on an electric car Costs of operation Uses for electric cars Sustainable transportation vs fossil fuels Questions and Answers

22 Uses for Electric Vehicles Pure electric vehicles –Daily commuting and in-town driving –Great for circular business delivery routes (e.g., mail carriers) –Excellent for short trips (no engine warm-up needed) Efficient and non-polluting even when “cold” Prius gets 25 mpg for first 5 minutes! –Some vehicles may have speed limits Freeway capable EV’s exist (mostly conversions for now) –Range is only limiting factor (may be reduced in winter) Low battery specific energy vs heat engine fuel Lack of rapid recharging/battery swapping infrastructure Hybrid (HEV) and Plug-in Hybrid Electric Vehicles (PHEV) –Better (+50%) range for long trips + efficiency –Honda Insight (EPA 70 mpg) owners often report 1000 miles/tank –Plug-in Prius (Hybrids Plus) 1620 mi on 9.27 gal (171 mpg + electricity) Consider Budget/Flexcar for those infrequent long trips

23 Electric Motor Torque and Power Siemens 5105WS12 at 312 Volts Insight torque 79 ft lbs at 1500 RPMInsight power 54.4 KW at 5700 RPM

24 Solar Powered Electric Vehicles

25 PV charging infrastructure combined with plug-in vehicles tied to the grid (V2G) will provide peak shaving, load leveling and backup power. EVs and PVs in the parking lot or garage can power a factory or home. The Clean Power/Transportation Solution Almost Half a MWh of storage in the parking lot Photo courtesy Donald Aitkin 2 kW of PV per parking space

26 Agenda How electric cars work Maintenance on an electric car Costs of operation Uses for electric cars Sustainable transportation vs fossil fuels Questions and Answers

27 Fuel Efficiency and Climate Change Assumptions: $3.50/gal, $.05/kWh nighttime rate, 40kWh/gal, 23#sCO2/gal * This column includes upstream CO 2 emissions for exploration, extraction, transport, refining and distribution of gasoline, as as well as CO 2 emissions from the California mix of power plants that produce electricity to charge electric vehicles. Vehicle Type $ Gas 25 Mi. /Day kWh 25 Mi. /Day $/year 25 Mi. /Day Gal/yr 25 Mi. /Day Tons of CO2/Yr Tailpipe * + Tons of Upstream CO2/Year 10 MPG Gas $ MPG Gas4.3750$ MPG Gas2.9334$ MPG HEV2.2025$ MPG HEV1.7520$ Plug-in HEV 25 Mile range 05$ Battery EV 03$ Solar/Electric 01000ZERO

28 The real measure of efficiency It took 3.5 billion years and rare geologic events to sequester hydro carbons and build up O 2 in the atmosphere 3.5x10 9 Years X 3.5x10 8 TWh/year Solar Energy = 1x10 6 TWh Oil Total 1.2x10 12 TWh Solar Energy = 1 TWh Oil Energy Using direct solar energy is 1,200,000,000,000 X more efficient than using oil

29 Global Energy Potential Renewables Forever terawatt hours /YEAR Direct Solar Radiation 350,000,000 Wind 200,000 Ocean Thermal 100,000 Biofuel 50,000 Hydroelectric 30,000 Geothermal 10,000 Tidal/Wave 5,000 Energy Stored in the Earth (Use it once and it’s gone) terawatt hours TOTAL Coal 6,000,000 Natural Gas (US Peak 2004) 1,500,000 Uranium 235 (US Peak 2008) 1,500,000 Petroleum (US Peak 1970, World Peak 2010) 1,000,000 Tar Sands 800,000 World stored energy consumption = 70,000 terawatt hours/year

30 Agenda How electric cars work Maintenance on an electric car Costs of operation Uses for electric cars Sustainable transportation v.s. fossil fuels Questions and Answers

31

32 Backup

33 The fossil fuel age on the scale of human history Native Americans lived on this land for 12,000 years without diminishing its bounty In 150 years of burning fossil fuel the Earths 3 billion year store of solar energy has been plundered

34 US Oil Discoveries Peaked in 1930 US Oil Extraction Peaked in 1970 “ America is Addicted to Oil” Reality Check: This is not a projection it is historical data from the petroleum industry. In a more perfect world the US might have noticed a trend after discoveries peaked in In a less than perfect world the US would have responded to peak extraction around Ignoring the realities of finite resources puts future generations at risk. We are the future generation. US Oil Consumption Will Peak 200?

35 World Peak Oil Gray Area Shows the Range of Forecast Peak Conventional Oil Reserves Source Peak Date SourcePeak Date F. Bernabe, ENI SpA 2005 C. Campbell, Petroconsultants J. Mackenzie, WRI International Energy Agency US DOE < 2020 Petroleum Industry US Oil “production” has been declining at an average of 2%/year since US Oil imports have been increasing at an average of 4%/year since 1985.

36 Advantages of Sustainable Energy Finite fuel supply Ugly infrastructure Polluted air / Climate change Extraction site devastation Polluted land Spills and polluted water Energy resource wars Susceptible to terrorism Unlimited energy source Aesthetically superior Clean air / Zero emissions No extraction sites Healthy land No water pollution No conflict over free sunshine National and individual security Fossil Fuel DependenceSolar Independence

37 Combustion Economy Agrarian Economy Solar/Electric Economy combustion depletes stored energy resources, reduces the quality of essential resources and will cause conflict and economic collapse Reliance on fossil energy has allowed population growth that can not be sustained by manual labor or beasts of burden Moving toward reliance on clean energy from the sun will stabilize the quality of essential resources and allow positive evolution QUALITY OF LIFE FUSSIL FUEL USE RENEWABLE ENERGY USE


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