Homemade electric truck project exposes Achilles heel of EV conversions: weight
We've showcased homebuilt electric-vehicle projects in the past, and they're comfort reading for this group. Honest, hardworking people with strong environmental commitments and a focused determination to exorcise themselves of fossil-fuel dependence, even if the effort makes no economic sense to others. The story of John Joseph and son Adam converting a $500 Chevy S-10 pickup follows similar story lines. They own an auto-repair shop in Virginia, the son did this before as a school project, gas prices going up, yada yada yada.
This story, however, offered a quick glimpse into the problem of weight. The S-10 is a nimble, spirited little runner at about 2,800 pounds. By the time the father-son converters were finished, it was tipping the scales at 5,700 pounds. That's more than a fully loaded Ford SuperCrew fullsize pickup. The heft comes from 24 6.4-volt batteries (and the mounting frames) wired in series for 154 volts, plus a 12-volt battery for the truck's accessories.
The Joseph clan carved off 1,200 pounds by cutting steel where they could, but it's still a massively heavy truck. And the conversion cost $20,000. It seems that many homemade conversions still rely on beastly lead-acid batteries because they're the cheapest and they don't overheat. But my question remains: where is the point of diminishing returns on these conversions? Is there a formula that helps home-based enthusiasts reach a balance between weight and power so they're not adding batteries to overcome more and more weight?
[Source: Peter Dujardin / Daily Press]
Reader Comments (Page 1 of 1)
Wayne 10:31PM (3/16/2008)
My S10 conversion resulted in a total of $8750, 4470 lbs, 60 mile range with an average speed of 50 mph. Top end is 75 mph. I commute a total of 41 miles per day round trip. I recharge in about 6 hours (on average) for a total cost of roughly $0.90. That works out to about 2.2 cents/mile. The truck used to get 22 mpg and at a current average price of $3.19/gallon in this area for gas, that would work out to about $0.14 to $0.15/mile on gasoline. I LIKE saving $0.12/mile. That's roughly $1,440 per year savings on gasoline alone. Not to mention no oil changes, air filter changes, etc., etc. Oh, and in MY humble opinion - the S10 is one of the best small pickups ever manufactured. That's why I own a total of 4 of them. Within two years, they will ALL be 100% electric.
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Chris M 11:35PM (3/16/2008)
Historical note: GM made and sold a few S10 EVs back when they were making the EV1. The GM S10 EV used the same motor and motor controller that was in the EV1.
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Weight Conscious Reader 8:31PM (4/01/2008)
The specifications for a 2002 Chevrolet S10 extended cab indicate it weighs 4,200 pounds (specifications can be seen at http://www.conceptcarz.com/vehicle/z4820/Chevrolet_S10.aspx#stats). John Joseph's linked email indicates his S10 weighs 4,510. Based on this information, it appears the conversion added 310 pounds to the truck. This would be well within the gross vehicle weight rating, and well within the intended design limits of this small pickup, and the additional weight appears to be in an ideal location (low and in the center of the chassis).
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Jeff 6:33PM (5/23/2008)
Wayne, can you post pictures of your conversion of your truck? Did you put any batteries in the front hood area? I was thinking of making one but wasn't quite sure how easy/difficult it would be. My email is jmar 42 at gmail.
Jeff--
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D 10:18PM (7/22/2008)
How come no one talks about a electric vehicle that incorporates Toyotas prius technology (drivetrain electric generation, the old bicycle tire light idea) and the use of a small hydrogen engine to recharge the batteries. Even a small one stroke biodiesel engine to recharge the battery would work. Maybe even a solar panel on the roof of the vehicle for extra juice. The engine should be for recharging the battery only, not for powering the vehicle at any speed.
A 100% electric driven car. No plugin (although the option should be there) necessary. I just don't understand this all seems like a no brainer to me.
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Nick 3:09PM (8/02/2008)
I completely agree I am currently in the process now of converting a 79' Chevy LUV to electric. It will have a full tonneau cover of solar panels over the bed with hydraulic lifts for bed/battery access, along with one set into the roof of the cab for a cleaner more aerodynamic look. I am also currently trying to source a small 15-25hp diesel engine that will be set up to run on biodiesel I already refine for use in my 94' Dodge 1 ton with a cummins. The small diesel will be hooked up to a generator and have it's own 5 gallon tank for fuel. The idea is that it will charge during the 9 hours I am at work in the Phoenix, AZ sun for the drive home and the small diesel will be for faster charges when more range is needed (use of full range one way with no time to rely solely on the solar panels to recharge the batteries). I am still looking at battery options but am most considering going with the Optima Blue Top deep cycle batteries. My commute is 67mi round trip, wish me luck.
Ben Nelson 12:36AM (10/14/2008)
Electric vehicles can be made much lighter than this, and much more economically as well.
My Electro-Metro conversion has 6 lead acid batteries, each weighing about 75 lbs. Considering the loss of the radiator, gas tank, and everything else connected to the engine, I don't think it weights too much more that the car did as a gasser.
I was also able to do the conversion for about $1200. Granted, it's more than a bit "home-brew", but will do 20 miles on a charge, go up to 45 mph, and gets me to work, grocery store, library, and to all the other local attractions.
It's not for everybody, but works for me. I have a gas Chevy S10 that I use for longer trips, which I am seriously considering hybridizing.
http://www.evalbum.com/1595
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zx2EV 9:56PM (2/10/2009)
This article appears to be very inaccurate in many ways. I can't imagine spending 20k on a lead acid conversion (unless you spent 10k on the car alone) and the weight listed is horribly wrong. While the conversion may well have added around 1,000lbs to the car, the numbers quoted in this article just don't add up. There is NO WAY this truck weights 5,700lbs.
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trump 10:11PM (2/15/2009)
fIrst of all this would have the batteries at 120lbs a piece Seems way out of line. And what about the ICE that is no longer there. that should offset a l ot of batteries?.
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Andy 7:57PM (4/27/2009)
The electric motor is pretty heavy, so don't go figuring that you can save 800 lbs by removing the ICE.
If the poster who said this vehicle was 5700 lbs, based on the info from the door pillar label - you're probably reading weight CAPACITY, not empty vehicle weight This is the weight of the vehicle PLUS the allowable payload, including people.
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Tim 8:56AM (12/14/2006)
Many battery manufacturer's are "getting the led out" and shrinking the tech too. Time will solve much of these problems. So will demand! So Demand Now!
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Monkey 11:15AM (12/14/2006)
"They own an auto-repair shop in England"
No, they don't. They very obviously live in Virginia, USA.
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Peter 11:52AM (12/14/2006)
The root source of the problem is underdeveloped battery technology. Their conversion could be much lighter if they used NiMH or Li-Ion batteries because they offer much better energy density (energy stored/weight). Of course, either of these options would also have been significantly more expensive.
With time, however, the cost of current battery technology will go down and totally new battery technologies will be developed. Remember, it took 100 years to get the internal combustion engine to the point where it is today. The fact that EVs like the EV1, Tesla, and RAV4 EV are even in the same league as the modern gasoline car is a testament to the huge potential of the electric car.
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Nick 2:29PM (8/02/2008)
First off I like electric cars and hope that they become capable of replacing the internal combustion motor in the near future. However you do realize that the electric car has been around longer than gas and diesel powered cars right?
Mike Magda 12:30PM (12/14/2006)
Corrected, thanks for the sharp eye.
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Howard Lee Harkness 4:43PM (12/14/2006)
I think a series hybrid is currently a better solution than a straight EV. A diesel can be made quite efficient when run at a constant RPM and load, and it only has to be big enough to supply the average power required, allowing the battery to store and release the energy needed for acceleration.
I suspect a series hybrid could be made a whole lot lighter than the 2000 lbs added to this S10, making it even more efficient.
Supposedly, the PbSO4 batteries were chosen because they are cheaper than the alternatives. Considering the fact that PbSO4 will give fewer recharge cycles than even standard LiON, I suspect that's false economy.
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robertplattbell 12:03PM (7/15/2007)
It is intersting that the article does not mention speed, range, or drivability of the vehicle, just the weight of the vehicle. If the vehicle performs well, who cares about how much it weighs?
Considering the people involved are making a vehicle from "off the shelf" components without the resources of a major automaker's engineering facilities, it is still a pretty impressive accomplishment.
Having lived in Northern Virginia, I can tell you the average speed travelled (even on the beltway) is about 35 mph. My car computer reminded me of this every day I lived there. "Average Speed: 35 mph".
For many people, a commuter car that traveled on local roads at speeds of 0-50 mph with a range of 50 miles or less would suit 90% of their driving needs. My commute, for example, was 20 miles round trip, on local roads with a max speed limit of 45 mph. Many people in Northern Virginia use a 6,000 Chevy Suburban for this kind of trip. A golf cart would almost suffice.
It sounds to me like the Joesph's wanted a direct substitute for a gasoline-engined vehicle - with the corresponding range and speed of one. In order to achieve this, a huge battery bank is required, hence the weight.
I am curious as to how much less this vehicle would weigh if the range and speed were reduced to that of a commuter car.
Also, the Chevy S-10, and a ton and half to start with, is hardly a "light a nimble" vehicle. Actually, it is a total POS truck, and a poor choice (IMHO) for an electric conversion.
This is an interesting "blog" in that it is not too enthusiastic about electric vehicles....
Hmmmm......
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John Joseph 9:53AM (8/17/2007)
My EV S10 wt. is 4510 LBs,not 5700 LBs. Please currect this, I had it weighed on VA.cert. scales. I do agree that the batteries are a weight problem, better batteries are needed. Thanks John Joseph
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