AAA-SRJC-EAA EV Conversion
AAA-SRJC-EAA EV Conversion Donor Car Analysis
Chris Jones, Electric Auto Association,
Updated October 16, 2009
Summary
We need to obtain a donor car for our EV conversion grant project that meets the following specifications:
|Make and Model |Ford Focus |
| |Nissan Sentra |
| |Toyota Corolla |
| |Honda Civic |
| |Mitsubishi Lancer |
| |Mazda 3 |
|Transmission |Manual |
|Body style |4 door sedan |
|Year |2000 or newer |
|Condition |Excellent, except for motor |
|Color |Light |
We are approaching local dealerships asking for a donation or discount in exchange for their logo on the vehicle, text book and web site. We have received positive responses, but after four months, no vehicle matching our requirements has been offered. We need a car by August 15th 2009 to proceed with the project to meet our June 2010 deadline; hence we need to purchase a vehicle. If we do not receive a donation or discount by August 1st we will go on the open market and buy the nearest vehicle that meets our needs.
Since the state-of-the-art EV components we want to use cost more than the $25,000 grant we were awarded, we are sensitive to the price of the vehicle. Fortunately since we will be removing the engine, a high mileage vehicle may be acceptable which could contribute to lowering the price. But the vehicle needs to be otherwise in excellent condition in order to motivate students to participate in our growing EV program, to generate good photographs for the textbook, and to draw positive responses when being shared with the public to promote our program.
Utilizing local dealers would help draw community support for our program that is in place to train people for jobs at these dealerships, as well as demonstrate the viability of replicating our program at other schools which would need their own local support. To determine if they respond with competitive offers, classified ads for vehicles that meet our requirements on Auto Trader were reviewed, and the following vehicles were found to have the lowest price while meeting the above criteria within 600 miles of the Santa Rosa Junior College on July 2, 2009:
|Make and Model |Price |Year |Odometer |Location |Miles from SRJC |
|Ford Focus |$3,995 |2004 |125,000 |San Mateo |67 |
|Nissan Sentra |$4,900 |2002 |87,876 |Los Altos |120 |
|Hyundai Elantra |$4,990 |2003 |74,500 |Fremont |73 |
|Toyota Corolla |$4,995 |2000 |98,540 |Oxnard |353 |
|Honda Civic |$4,995 |2001 |151,794 |Hawaiian Gardens |410 |
|Mitsubishi Lancer |$4,995 |2005 |68,023 |Roy, UT |594 |
|Mazda 3 |$8,750 |2005 |70,520 |Fallbrook |466 |
Source:
Cost savings of approximately 20% or up to $1,500 could be obtained from private party sellers, but it is not recommended due to the reasons for going with a local dealer above, as well as to minimize the risk of the condition for this car that will be need to be reliable for SRJC fleet use.
The following sections summarize the analysis performed to arrive at these conclusions.
Table of Contents:
1. Distance to Dealer
2. Age of Vehicle
3. Body Style
4. Transmission
5. Curb Weight
6. Safety
7. Color
8. Tire Rolling Resistance
9. Model Selection
10. Blue Book Values
11. Dealer Asking Prices
12. Pictures
1. Distance to Dealer
Commensurate with population, Northern California has about 5X more used cars for sale than Sonoma County, and all of California has about 20X more:
[pic]
Source:
Therefore if necessary we should look around Northern California if price or availability becomes an issue.
2. Age of Vehicle
Looking for older cars to save money or maximize the reuse of a vehicle is attractive, but 93% of the cars for sale are 2000 or newer:
[pic]
Source:
If an older, less expensive model was found and the conversion design work was not applicable to newer models, it might severely limit the usefulness of applying our work to other vehicles, so we need to obtain a late model vehicle from 2000 or newer.
3. Body Style
The most common body style available is the 4-door sedan, accounting for 25% of all used cars for sale, hence it will be the focus of our conversion, for maximum utility and popularity:
[pic]
Source:
4. Transmission
For maximum efficiency and performance, we need a manual transmission and clutch for our EV conversion. Stock automatic transmissions as well as purpose built EV single gear reduction boxes can reduce efficiency by 10 to 20% from manual transmissions due to suboptimum gear ratio over the range of speeds and accelerations required in a car. Power limiting could offset this reduction in efficiency, but given marginal acceleration rates to begin with, it would lead to an unsafe configuration. Given the range is already limited, and this program is in place to reduce energy use, we need to use a transmission.
ICE automatic transmissions are only about 1% less efficient in sedans on average, but can be as much as 10% worse and 14% better:
[pic]
Source:
Any automatic transmission loss is mostly due to slip in the torque converter, which isn’t necessary in an EV whose motor doesn’t need to spin at a stop. However, even if the torque converter was removed, the ICE shift points would be at too low of an RPM for an EV, which would lead to lower efficiency and shorter range. This might be able to be reprogrammed, but this development work is out of scope for our first state-of-the-art conversion as an organization. But we believe eliminating the need to manually shift while maintaining maximum efficiency and performance is important to bridging the gap of energy and battery capacity, so this or an automated manual transmission such as an option in the Volkswagen Passat may be looked at in the future.
Fortunately the transmission does not need to be used at all, except for reverse to save adding adding reversing contactors, and can be used less often, and the clutch does not need to be used at startup. To maintain quick shifting for safety and performance reasons, the clutch also needs to be retained.
Unfortunately as you can see in the graph in the previous section, this severely limits our donor vehicle choices since only 6% of used sedans come with manual transmissions. 24 to 31% of all coupes, hatchbacks and convertibles come with manual transmissions, probably for performance reasons. Some of these parts are interchangeable with their sedan counterparts, but the conversion time would be increased in this non-EV activity so it is recommended to obtain a donor sedan with a manual transmission.
The conversion design work we do should translate directly to coupe and wagon versions of the sedan we choose. Hatchbacks, as well as subcompact and mini vehicles, typically have shorter tail sections that can drastically reduce the available space for the rear traction battery pack while maintaining adequate crumple zone to maintain crashworthiness in the even of a rear-end collision, thus our work may not translate to hatchback versions.
5. Curb Weight
Compact cars, whose curb weights are between 2500 and 3000 pounds, are optimum for safe, medium range EV conversions using state-of-the-art components. Like all small cars, the Gross Vehicle Weight Rating (GVWR) vs. curb weight is high enough to be able to safely carry enough batteries and other EV components to travel far enough with enough power, but unlike the smaller subcompact cars, compacts tend to have enough space to comfortably accommodate taller people, and have proportionally more space under the hood and behind the rear axle to place enough batteries without impacting the crumple zones and hence crashworthiness.
Curb weight for compact cars tends to increase by an average of 23 pounds per year, most less than 20 pounds but the Sentra at over 40 pounds. This needs to be taken in to consideration when selecting a model year of a specific model:
[pic]
Source:
Mid-size cars are more popular and could be converted, but they would be more expensive. And since they do not have disproportionately more GVWR, they could not go any farther safely, which would lower their value. This could be problematic, given the high cost of these early low volume production EV components. Furthermore, their heavier weight would take more energy to propel, which is counter to the overall goal of this program to reduce energy use. Going from 2750 to 3250 lbs takes the average MPG of manual transmission sedans from 27 to 22 or a 23% increase in energy use:
[pic]
Sources: and
Here is a list of the used manual transmission sedans for sale vs. curb weight:
[pic]
Source:
SUVs could be converted, but they too are less aerodynamic which is counter to our energy reduction goals. And their GVWR to curb weight ratio from the factory is typically less than cars, and they are less aerodynamic, which would result in a reduction in range and power to weight ratio in a safe conversion. The Toyota RAV4 EV was an exception, but it was designed from the ground-up and tested to verify it was able to carry the extra load safely throughout the service life of the vehicle. Aftermarket modifications to the frame, brakes, steering and suspension may perform well short term under heavier loads, but they may fail in extreme handling situations or after repetitive use.
Trucks have significantly larger GVWR to curb weight ratio, so the lighter ones are popular for conversions, especially for heavier batteries such as lead acid. But for the sake of this project, since they are far less popular than sedans and SUVs probably due to lower seating capacity, our results would be less useful. They are also less aerodynamic, so they would be more expensive and take more energy to propel the same distance. A truck that had more batteries that took up the usable payload could potentially go farther safely, but due to its lower efficiency it could be cost prohibitive, and the bed of the truck would be unusable which would lower its value.
A compact conversion going greater than 50 miles with LiFePO4 batteries over their 5 year expected life requires adding approximately 200 pounds to the car's curb weight. This is due to the removal of 450 pounds of 4 cylinder engine, gas tank, exhaust system, starter battery and radiator, and replacing it with 650 pounds of traction batteries, electric motor, power electronics, mounts, interconnects and accessory battery. Staying under the factory GVWR specification results in a safe carrying payload reduction from over 900 pounds to over 700 pounds. This is considered acceptable for a 4 seat car, since the weight of 4 people and their belongings or groceries typically will not exceed 700 pounds for the short trips expected for a limited range car with a slow charge rate. Furthermore, some compact SUVs have little more than 700 pounds payload stock from the factory.
Adding the extra weight of the batteries does require placing the spare tire in the trunk which does impact available cargo area, making space for the rear battery pack under the trunk floor. Compact sedans, coupes and wagons tend to have enough space for the pack under the trunk floor while maintaining more than one foot of crumple zone behind them for safety. There is not enough space to put enough batteries where the gas tank is under the rear seat; modifications to the cab space could be done, but that could impact safety and greatly increase the effort of the conversion.
Unfortunately, 3000 pounds is just under the median sedan weight, so this reduces our choices by about 55%.
[pic]
Source:
Fortunately 16% of the top 6 used compact sedans listed above have manual transmissions, probably for performance reasons, since smaller cars tend to be economy cars which tend to come with smaller, lower powered engines, which tend to perform poorer with automatics than larger engines.
6. Safety
A common concern brought up about compact cars is their perceived lack of safety. Although the safest cars have above average weight, many compact cars are safer than average, and for most cars the death rate is low. And some of the heavier cars are far more lethal, particularly to others but some also to their own occupants due to increased rollover propensity such that the American Council for an Energy Efficient Economy (ACEEE) advocates that reducing average car weight would reduce overall deaths.
Per the ACEEE chart below, late 90’s compact cars that were safer than average included the Jetta and the Civic. Average compact cars included the Corolla, Sentra and Saturn. Only 44% of the compact models were less safe than average -- the Prism, Cavalier, Escort and Neon.
[pic]
Source: An Analysis of Traffic Deaths by Vehicle Type and Model, .
7. Color
The car needs to have light color interior and exterior – silver and white for sure, and probably tan, gold or beige -- to minimize heat absorption from the sun and hence minimize the load of the air conditioner on the traction battery pack. A 10 to 20% reduction in driving range can occur with the air conditioning on. Fortunately it doesn’t get too hot in Santa Rosa very often, but we want to do work that is applicable to most of the US where it can get much warmer.
But even if we had enough range, we need a vehicle that is energy efficient to meet the underlying goals of the program. This is a large enough problem for gasoline cars that the California Air Resources Board is considering requiring darker colored vehicles to have higher solar reflectivity to reduce air conditioning load and improve gas mileage. This can be achieved by adding small particles to the paint that affect the infrared spectrum but not the visible spectrum. This has already been achieved with metal roof paints for reducing stationary air conditioning loads.
The most common color is silver which is light. But black is more common than white; staying with the lightest colors further reduces our choices worst case by 57%, but some of the colors assumed below to be dark such as gray may actually be light gray which is closer to silver and acceptable, such as on the Honda Civic:
[pic]
Source:
8. Tire Rolling Resistance
Tires can affect a vehicle’s efficiency. If all tires were properly inflated it would save an estimated 5% of fuel consumption. If all tires were Low Rolling Resistance (LRR), another estimated 5% of fuel could be saved. Fortunately, there is not a fixed tradeoff of efficiency vs. traction. Unfortunately, not all tire rolling resistances have been measured, and none are labeled with a standard.
[pic]
Source: .
Tire rolling resistance tends to decrease with wear so new tires can reduce mileage, but typically do improve traction.
9. Model Selection
All cars less than 3000 pounds with manual transmissions for sale within 50 miles of Santa Rosa were considered at first:
|number for sale |make |model |2007 base model curb weight |start date |end date |big enough? |
|26 |Volkswagen |Jetta |3230 | | | |
|17 |BMW |3 series |3340 | | | |
|14 |Toyota |Corolla |2530 |1966 |n/a | |
|11 |Honda |Civic |2628 |1972 |n/a | |
|7 |Mazda |6 |3166 | | | |
|6 |Ford |Focus |2621 |2000 |n/a | |
|5 |Nissan |Altima |3055 | | | |
|5 |Saab |9-3 |3230 | | | |
|4 |Honda |Accord |3188 | | | |
|4 |Saturn |Ion |2752 |2003 |2007 | |
|3 |Cadillac |CTS |3509 | | | |
|3 |Mercedes Benz |C230 |3405 | | | |
|3 |Toyota |Yaris |2293 | | |no |
|2 |Dodge |Caliber |2966 |2007 |n/a | |
|2 |Lexus |IS 250 |3435 | | | |
|2 |Nissan |Maxima |3591 | | | |
|1 |Acura |TL |3623 | | | |
|1 |Audi |A4 |3428 | | | |
|1 |Chevrolet |Cobalt |3216 | | | |
|1 |Chrysler |PT Cruiser |3072 | | | |
|1 |Ford |Fusion |3151 | | | |
|1 |Hyundai |Elantra |2747 | | | |
|1 |Hyundai |Sonata |3266 | | | |
|1 |Jaguar |X-Type |3516 | | | |
|1 |Kia |Rio |2365 | | |no |
|1 |Nissan |Versa |2749 | | |no |
|1 |Volvo |S40 |3234 | | | |
|187 |Total | | | | | |
Source:
The Toyota Yaris, Kia Rio and Nissan Versa were eliminated because they are subcompacts with not enough interior space for average people and shorter tails and hence less rear battery space, but they only accounted for 3% of the listings.
Then to maximize the usefulness of our work, the Dodge Neon and Saturn Ion were eliminated since they have been discontinued in 2005 and 2007 respectively, and the Dodge Caliber was eliminated since it was introduced as late as 2007. The Hyundai Elantra was eliminated because there was only 1 for sale, hence not being very popular compared to other models.
This leaves us with the 6 most popular compact sedans with manual transmissions in the table below, with the lowest price being sold by dealers in May 2009:
|Make and Model |Lowest Price |Quantity for sale within 50 miles |
|Ford Focus |$4,688 |4 |
|Nissan Sentra |$5,995 |3 |
|Toyota Corolla |$4,995 |12 |
|Honda Civic |$5,995 |8 |
|Mitsubishi Lancer |$6,500 |9 |
|Mazda 3 |$7,995 |4 |
|Total | |40 |
Source:
This should give us enough choice to get the right vehicle for cosmetics and mechanical condition, as well as provide a path for at least a niche of others to follow.
10. Blue Book Values
Kelly Blue Book private party values for the base level trim of these 6 models drops dramatically as expected during the first 5 years. 1 year old cars cost $11-13K, but we should be able to get an older Focus under $4K, a Sentra under $5K, and a Corolla, Civic or Lancer for under $6K. Being newer, a Mazda 3 may cost closer to $9K unless a high mileage car is found.
[pic]
Source:
11. Dealer Asking Prices
As found in Kelley Blue Book Dealer values, dealers typically ask 25% more than private parties, and some of the cars come with expensive options. The least expensive car found within 50 miles was a Corolla with 162K miles for $5K, which should suffice for this project:
[pic]
Source:
Here is a list of the three lowest price cars of each model for sale within 125 miles on :
make |model |Color |year |miles |price |PP blue book |difference |dealer |miles from SRJC | |Ford |Focus |White |2002 |75,000 |$4,488 |$3,640 |23% |Pacific Auto, Auburn |92 | | | |White |2004 |125,000 |$4,688 |$4,355 |8% |Apple Auto Express, San Mateo |67 | | | |Silver |2004 |76,908 |$6,735 |$4,355 |55% |John Sullivan Chevrolet, Roseville |80 | |Toyota |Corolla |Sand |2001 |161,947 |$4,995 |$5,710 |-13% |Jimmy Vasser Toyota, Napa |25 | | | |Silver |2003 |187,956 |$4,988 |$8,005 |-38% |McMillen's Gold Country Motors, Grass Valley |104 | | | |Silver |2000 |109,823 |$6,950 |$5,220 |33% |Novato Toyota |26 | |Nissan |Sentra |Silver |2001 |unlisted |$5,995 |$4,585 |31% |Campbell Auto Finance, Gilroy |116 | | | |White |2003 |84,977 |$8,960 |$5,515 |62% |Marin Motors, San Rafael |35 | | | |Silver |2006 |77,027 |$8,988 |$7,035 |28% |Mike Harvey Honda, Burlingame |64 | |Honda |Civic |light gray |2002 |114,000 |$5,995 |$6,715 |-11% |South Valley Auto Wholesale, Santa Clara |86 | | | |light gray |2001 |71,000 |$5,999 |$6,035 |-1% |South Valley Auto Wholesale, |86 | | | |Beige |2001 |95,826 |$6,895 |$6,035 |14% |Apple Auto Express, San Mateo |67 | |Mitsubishi |Lancer |Silver |2003 |69,871 |$6,500 |$5,690 |14% |Oakland Acura |50 | | | |Silver |2006 |49,641 |$8,995 |$8,085 |11% |Saturn of Santa Rosa |4 | | | |Silver |2005 |36,000 |$9,995 |$7,090 |41% |Formula 1 Motors, Hayward |63 | |Mazda |3 |Silver |2004 |54,867 |$7,995 |$8,805 |-9% |Active Auto Sales, Corte Madera |37 | | | |White |2006 |44,952 |$10,988 |$10,700 |3% |Auto Sense, Orangevale |82 | | | |Silver |2006 |39,480 |$11,995 |$10,700 |12% |Gold Rush Chevrolet Subaru, Auburn |93 | |
12. Pictures
Here are pictures of the models under consideration. Sources vary from internet.
Ford Focus
Generation 1, 2000-2007
[pic]
Generation 2, 2008-present
[pic]
Toyota Corolla
Generation 8, 1998-2002
[pic]
Generation 9, 2003-2008
[pic]
Nissan Sentra
Generation 5, 2000-2006
[pic]
Generation 6, 2007-present
[pic]
Honda Civic
Generation 6, 1996-2000
[pic]
Generation 7, 2001-2005
[pic]
Honda Civic, continued
Generation 8, 2006-present
[pic]
Mitsubishi Lancer
Generation 7, 2002-2006
[pic]
Generation 8, 2007-present
[pic]
Mazda 3
Generation 1, 2004-2008
[pic]
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