Cheap electric car conversions could come from lead acids + supercapacitor
Posted Nov 2nd 2009 5:04PM by Sebastian Blanco
There's no debate that batteries for electric cars remain absurdly expensive and one of the main hurdles to widespread EV acceptance. A team of electric vehicle converters at the ChargeCar project at Carnegie Mellon University in Pennsylvania is trying to solve the puzzle by using low-cost lead acid batteries coupled with a supercapacitor and four electric motors. The powerplant was installed in some sort of Scion model in order to prove that the team's goal – expressed by team leader Illah Nourbakhsh to "use the cheapest hardware possible by making the smartest possible management software" – can work in real life.The real life implications of cheaper conversions like ChargeCar are important to the group. Nourbakhsh (pictured) says that getting energy back from regenerative braking will likely be much higher than people who rely on the U.S. Urban Dynamometer Driving Schedule standard may expect. The UDDS suggest six percent of the energy could be recouped, Nourbakhsh thinks it's more like 40 percent. To get a better idea if he's right, ChargeCar is asking for people to submit GPS logs, anonymously, in order to see how cars on the road actually perform. The ChargeCar team will use this data to write better software for EVs to "prepare for hills, junctions or other features that will affect its energy use."
There's a video of Nourbakhsh talking about the project after the jump.
[Source: New Scientist]
Reader Comments (Page 1 of 2)
FitFan 5:18PM (11/02/2009)
I wouldn't be surprised if the amount of regenerated energy from braking was higher than 6% for the average driver in the united states.
If you watch the average driver you will notice how often they overaccelerate and then have to brake to compensate. Accelerate, brake, repeat ... while I'm cruising along behind them never touching my brakes.
I think it would be fantastic if someone would come out with a retrofit kit for everyday cars. I would love to keep my little civic hatchback for another 5 years.
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Dave B 9:44PM (11/02/2009)
You're right about drivers stopping and starting excessively, especially in the city where they race from one stop light to the next.
Most cars are so close to the one in front of them, you would think they are drafting like the Talledega 500.
I used to be one of them until I got my Civic Hybrid, which gave me good feedback on the melieage I was getting. I learned that I got considerably better mileage when I left more space for the car in front of me......
Geronimo 5:50AM (11/03/2009)
Hi FitFan,
I can confirm your conviction that regenerative energy is higher than 6%. One aspekt of regenerative energy that has been completely neglected are the shock absorbers. There is a lot of energy in all those road bumps that is being completely wasted. Substitute conventional shock absorbers with ยต-processor controlled linear generators and you can at least double or even triple the energy regained from braking source.
Boyprodigy1 11:29AM (11/03/2009)
@ Gironimo
That's a really good idea!!! We should start up an ABG car company...
Dave 5:27PM (11/02/2009)
Nourbakhsh says he's only driven 2 EVs in his life.
Personally, I've driven numerous golf carts, several electric forklifts, an electric gator and probably a few things I can't think of off the top of my head.
The funny thing about EVs is that some people portray them as revolutionary when theyre actually ubiquitous. Theyre advantages are well known and so are their faults.
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paulwesterberg 6:17PM (11/02/2009)
Let me get this right, you are cutting on a guy for lack of experience with EVs when he helped to build a solar electric race car and has driven a rav4 EV for the last 9 years?
You don't like EVs based on your experience with golf carts? Thats like saying I don't like computers because I had a Radio Shack TRS-80 that was too slow and didn't have any good games.
Dave 6:26PM (11/02/2009)
I'm not cutting him for lack of experience. I'm cutting him for being full of crap and making strawman arguments.
I didnt say I don't like EVs. I believe they have several niches they fit very well.
paulwesterberg 7:05PM (11/02/2009)
He says that electric motors are well suited to urban commuting, but current battery chemistry is not well suited to the frequent discharge/charge cycle. What he is showing is that by adding an energy cache you can reduce battery cycles and increase battery lifespan. This makes EVs more affordable. You still have issues with maximum range, but most people don't drive long distance on a daily basis.
jpm 8:27PM (11/02/2009)
your point is irrelevant.....the talk is about road-going EVs... which are obviously not widespread.
Mike 5:36PM (11/02/2009)
Superwhat?
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AussieBloke 5:48PM (11/02/2009)
What's a capicator?
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paulwesterberg 6:19PM (11/02/2009)
What's Wikipedia?
What's Google?
http://lmgtfy.com/?q=supercapacitor&l=1
AussieBloke 6:22PM (11/02/2009)
Read my comment again. Carefully.
AussieBloke 6:24PM (11/02/2009)
Then read the title of the article. Carefully.
Matt 6:30PM (11/02/2009)
LOL
Mike 5:48PM (11/02/2009)
It's super that's what it is!
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3PeaceSweet 6:27PM (11/02/2009)
Supercaps & NiMH would be a good combination.
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Ernie 3:22PM (11/03/2009)
No, because this is about car *conversions*. Due to certain patent restrictions, consumers can't actually get NiMH batteries larger than a D size. If you feel adventurous, you can get them with solder tabs and then build a very large battery pack over the course of many hours. And then you get to build your own battery management system, because noone builds *them* for NiMH batteries either.
Oh, and at the end of the day, you're better off buying large format Li-Ion batteries from Thunder Sky, because you'll get better performance for the same amount or less money. For whatever reason, in spite of being an inferior battery chemistry, NiMHs don't cost less.
Robert 6:30PM (11/02/2009)
This should work if they use hi tech lead acid batteries like those being developed by FireFly Energy. These use a lead sponge plate instead of solid lead. Much more surface area for more contact between plates and electrolyte for better capacity and performance plus a coating that resists sulfating which is the common cause of lead-acid battery failure. They also weigh less since there is less lead. They will cost more than convention lead batteries but longer life, more energy storage per pound and per volume, and lighter weight will make them less expensive for the life cycle. Still much less costly than lithium batteries.
Capacitors are electrical energy storage devices that are not batteries. Think of a compressed air storage tank. It stores energy in the form of compressed air. All electronics have many capacitors which store a small electrical charge. Super capacitors are similar, just much bigger (like on steroids) to store usable power to power a vehicle for a short distance.
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dieqast 7:56PM (11/02/2009)
Great lecture and initiative. The insights from the data retrieved from commuters are also interesting to the car makers, who can adapt their cars to certain regions instead of oversizing it to fit everyone. The problem lies with the commuters who are too lazy to upload GPS info etc. I think the car should be the uploader (hold on privacy lawyers!).
Again supercaps is very underestimated technology. IIRC, Musk did his final paper on the subject. The buffer concept should be applied to all future EV's, downsizes batteries significantly, keeps temperatures lower etc. see the lecture. But also parallel hybrids could use the concept in another form. Think of flywheel-diesel parallel hybrids for example.
The strange thing is he mentioned that a supercap for a 400v system would be around 16k USD. If that is true, how can the Aptera 2e at 40k USD max have a 320v system with a supercap?? Considering environmental impact of the metals in batteries, I think we should move towards (relatively) cost-effective and low-voltage lithium based battery systems instead of nickel or even lead-acid.
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