EV 101 Owning and Operating an Electric Vehicle

EV 101: Owning and Operating an Electric Vehicle Gary Graunke Oregon Electric Vehicle Association (Oregon chapter of the Electric Auto Association) December, 2007

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

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

How Electric Cars Work • Throttle variable resistor tells motor controller desired speed Charger – 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 Traction Batteries DC-DC Contactors Speed Pedal Motor Controller Aux. Battery Contactors Motor Differential Just like a toy car, but high voltage and high current (danger!)

Throttle Linkage Zap Throttle Linkage Converted Honda Insight Linkage Electric Output Mechanical Input S 10 Electric Pickup Linkage

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 Cafe. Electric Zilla 1 K Curtis 1231 C (ZAP) Contactors (ZAP) Electricity is the only alternative fuel you can create when you go downhill

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) Delta. Q charger (ZAP) Brusa NLG 512 charger Manzanita Micro PFC

DC-DC Converters • Most EV’s have small 12 V 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

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

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

Managing Safety Issues • Service disconnects to break HV battery string into small parts – Voltages must be below 60 V 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 H 2 SO 4, 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

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)

Battery Balancing • Relative cell state of charge varies over time full 2. 16 V – Manufacturing variance – Different operating temperature – Series charging increases differences in state of charge voltage empty 1. 75 V • 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 overcharge – Ideally measure individual cell voltages – Measuring highest, lowest batteries is good approximation Periodic rebalancing improves battery pack longevity full voltage empty

Capacity Variance with Aging • As batteries age capacity variances increase Overdriving full 2. 16 – More imbalance! • Easier to overdrive voltage – Weakest cell voltage plunges and may even reverse polarity! – Best case: shorter range empty 1. 75 0 volts • 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 overcharging full voltage empty Check aging pack batteries for varying capacity

Use Appropriate Batteries 12 V batteries need sufficient power to stay above 10. 5 V (short bursts ok)

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

Battery Management Add-ons • Hart Batt-Bridge is an “idiot light” costing <$10 – LED lights when two halves of pack differ by > 2 v – One cell empties/reverses first – Charge now or go “turtle mode”! • Power. Cheq modules – Keep each two adjacent batteries voltage difference <. 1 V – Works 24 X 7 while driving, charging, parked – Limited current—keeps balanced pack balanced – Requires N-1 modules for N batteries

More Battery Management Aids • Manzanita Micro MK 3 regulator prevents overcharge – Backs off charger when individual battery full – Limits battery voltage – Data logging • Hart balancer relay module (30 A capacity) – Scans batteries to measure voltage – Connects any battery to isolated “flying” battery or DCDC – Can take charge from higher state-of-charge batteries – Gives charge to lower state-ofcharge batteries

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

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 • S 10: 66 mpg equivalent • NEV: 245 mpg equivalent • Electric motors last! • 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 – AC motors: 1 moving part – DC motors: brushes EV owners replace batteries when heat engine owners replace vehicle

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

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

Electric Motor Torque and Power Siemens 5105 WS 12 at 312 Volts Insight torque 79 ft lbs at 1500 RPM Insight power 54. 4 KW at 5700 RPM

Solar Powered Electric Vehicles

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

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

Fuel Efficiency and Climate Change Vehicle Type $ Gas 25 Mi. /Day k. Wh 25 Mi. /Day $/year 25 Mi. /Day Gal/yr 25 Mi. /Day Tons of CO 2/Yr Tailpipe *+ Tons of 10 MPG Gas 8. 75 100 $3200 915 10. 5 13. 7 20 MPG Gas 4. 37 50 $1600 460 5. 3 6. 8 30 MPG Gas 2. 93 34 $1050 305 3. 5 40 MPG HEV 2. 20 25 $800 230 2. 6 3. 4 50 MPG HEV 1. 75 20 $640 180 2. 1 2. 8 Plug-in HEV 25 Mile range 0 5 $100 0 0 . 7 Battery EV 0 3 $65 0 0 . 4 Solar/Electric 0 1 0 0 0 ZERO Upstream CO 2/Year Assumptions: $3. 50/gal, $. 05/k. Wh nighttime rate, 40 k. Wh/gal, 23#s. CO 2/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.

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. 5 x 109 Years X 3. 5 x 108 TWh/year Solar Energy = 1 x 106 TWh Oil Total 1. 2 x 1012 TWh Solar Energy = 1 TWh Oil Energy Using direct solar energy is 1, 200, 000, 000 X more efficient than using oil

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

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

Backup

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

“ America is Addicted to Oil” 1930 US Oil Extraction Peaked in 1970 US Oil Discoveries Peaked in US Oil Consumption Will Peak 200? 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 1930. In a less than perfect world the US would have responded to peak extraction around 1975. Ignoring the realities of finite resources puts future generations at risk. • We are the future generation.

World Peak Oil Gray Area Shows the Range of Forecast Peak Conventional Oil Reserves Source F. Bernabe, ENI Sp. A Source C. Campbell, Petroconsultants Peak Date 2005 -2010 J. Mackenzie, WRI 2007 -2014 International Energy Agency 2010 -2020 US DOE Petroleum Industry < 2020 -2040 US Oil “production” has been declining at an average of 2%/year since 1985. US Oil imports have been increasing at an average of 4%/year since 1985.

Advantages of Sustainable Energy Fossil Fuel Dependence • Finite fuel supply • Ugly infrastructure • Polluted air / Climate change • Extraction site devastation • Polluted land • Spills and polluted water • Energy resource wars • Susceptible to terrorism Solar Independence • 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

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