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
Charger
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!)

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

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)
Contactors (ZAP)
CafeElectric Zilla 1K
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 charger
Manzanita 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 H2
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
full 2.16V
voltage
empty 1.75V
overcharge
full
voltage
empty
Periodic rebalancing improves battery pack longevity

14. Capacity Variance with Aging
Overdriving
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
full 2.16
voltage
empty 1.75
0 volts
overcharging
full
voltage
empty
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 RPM
Insight power 54.4 KW at 5700 RPM

24. Solar Powered Electric Vehicles

25. Almost Half a MWh of storage in the parking lot
The Clean Power/Transportation Solution
2 kW of PV per parking space
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.
Almost Half a MWh of storage in the parking lot
Photo courtesy Donald Aitkin

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
Vehicle Type
$ Gas 25 Mi. /Day
kWh
25 Mi. /Day
$/year
Gal/yr
Tons of
CO2/Yr
Tailpipe
*+ Tons of Upstream
CO2/Year
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
4.5
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 5
$100 .7
Battery EV 3
$65 .4
Solar/Electric 1
ZERO
Assumptions: $3.50/gal, $.05/kWh nighttime rate, 40kWh/gal, 23#sCO2/gal
* This column includes upstream CO2 emissions for exploration, extraction, transport, refining and distribution of gasoline, as as well as CO2 emissions from the California mix of power plants that produce electricity to charge electric vehicles.

28. The real measure of efficiency
It took 3.5 billion years and rare geologic events to sequester hydro carbons and build up O2 in the atmosphere
3.5x109 Years X 3.5x108 TWh/year Solar Energy = 1x106 TWh Oil Total
1.2x1012 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 ,000, Wind ,000
Ocean Thermal ,000
Biofuel ,000
Hydroelectric ,000
Geothermal ,000
Tidal/Wave ,000
Energy Stored in the Earth
(Use it once and it’s gone)
terawatt hours TOTAL
Coal ,000,000
Natural Gas (US Peak 2004) ,500,000
Uranium 235 (US Peak 2008) ,500,000
Petroleum (US Peak 1970, World Peak 2010) ,000,000 Tar Sands ,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

32. Backup

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

34. US Oil Discoveries Peaked in 1930 US Oil Extraction Peaked in 1970
“ America is Addicted to Oil”
US Oil Discoveries Peaked in US Oil Extraction Peaked in 1970
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.

35. Range of Forecast Peak Conventional Oil Reserves
World Peak Oil
Gray Area Shows the
Range of Forecast Peak Conventional Oil Reserves
Source
Peak Date
F. Bernabe, ENI SpA
2005
C. Campbell, Petroconsultants
J. Mackenzie, WRI
International Energy Agency
US DOE
< 2020
Source Peak Date
Petroleum Industry
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.

36. Advantages of Sustainable Energy
Fossil Fuel Dependence
Solar Independence
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

37. Solar/Electric Economy
QUALITY OF LIFE
FUSSIL FUEL USE
RENEWABLE ENERGY USE
Combustion Economy
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