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Supercapacitor Track Car Starter

chris p

Aug 11, 2016
1
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Aug 11, 2016
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Hi guys just to introduce myself first. I’m Chris I’m an instrument technician by trade and please go steady with me, it’s been about 6 years since I’ve done any kind of circuit design at university. I also have no experience with super capacitors or circuits of this design.

I’m sure most of you have seen this video of a guy using a bank of super capacitors to start his car.

Using these capacitors
http://www.digikey.com/product-search/en?x=19&y=16&lang=en&site=us&KeyWords=1182-1016-ND


Now I can appreciate that this isn’t really a practical alternative to a conventional battery in a daily driver, however this is not what I want to use it for. I’d like to use this for my classic mini track car due to its huge weight savings over even a light weight race battery. The idea would be to isolate the capacitors and jump start the engine using a conventional battery pack at the beginning of the day (I’ve read somewhere that it’s probably not a good idea to jump it, not sure why?). The capacitors would then be able to start the car between track sessions or if I end up spinning it and stalling out on track.

My questions are really firstly is it feasible? If so would there be any issues with using two of these in parallel for the extra capacity? I think this would be wise due to it being an older engine, even though its usual pretty good it is very highly tuned and can spit its dummy out now and again. Also does it need a voltage balancing circuit to prevent over charging one of the capacitors or can I get away without this? What are the consequences of overcharging one? And finally is there any safety concerns to take into account i.e. will it get hot and what is likely to happen if it fails, bearing in mind it will be located close to the fuel tank. I wouldn’t be keen on putting a small bomb next to my fuel tank.

I appreciate I have a hell of a lot to research to do before building this but I’d like to know if it’s feasible before committing to hours of reading

Thanks for any help, even if it is to totally destroy my hopes and dreams of a super light battery alternative.
 
Last edited:

Colin Mitchell

Aug 31, 2014
1,416
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Aug 31, 2014
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You have to look at the energy stored in a super capacitor, compared to its weight.
 

Herschel Peeler

Feb 21, 2016
401
Joined
Feb 21, 2016
Messages
401
Hi guys just to introduce myself first. I’m Chris I’m an instrument technician by trade and please go steady with me, it’s been about 6 years since I’ve done any kind of circuit design at university. I also have no experience with super capacitors or circuits of this design.

I’m sure most of you have seen this video of a guy using a bank of super capacitors to start his car.

Using these capacitors
http://www.digikey.com/product-search/en?x=19&y=16&lang=en&site=us&KeyWords=1182-1016-ND


Now I can appreciate that this isn’t really a practical alternative to a conventional battery in a daily driver, however this is not what I want to use it for. I’d like to use this for my classic mini track car due to its huge weight savings over even a light weight race battery. The idea would be to isolate the capacitors and jump start the engine using a conventional battery pack at the beginning of the day (I’ve read somewhere that it’s probably not a good idea to jump it, not sure why?). The capacitors would then be able to start the car between track sessions or if I end up spinning it and stalling out on track.

My questions are really firstly is it feasible? If so would there be any issues with using two of these in parallel for the extra capacity? I think this would be wise due to it being an older engine, even though its usual pretty good it is very highly tuned and can spit its dummy out now and again. Also does it need a voltage balancing circuit to prevent over charging one of the capacitors or can I get away without this? What are the consequences of overcharging one? And finally is there any safety concerns to take into account i.e. will it get hot and what is likely to happen if it fails, bearing in mind it will be located close to the fuel tank. I wouldn’t be keen on putting a small bomb next to my fuel tank.

I appreciate I have a hell of a lot to research to do before building this but I’d like to know if it’s feasible before committing to hours of reading

Thanks for any help, even if it is to totally destroy my hopes and dreams of a super light battery alternative.

2.7 V and 350 F comes to about 1,200 coulombs for one capacitor. Compare that to a AA NiMH battery that can deliver 7,200 coulombs. Not much power to start a car with. Where did I go wrong?
 

BobK

Jan 5, 2010
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7,682
2.7 V and 350 F comes to about 1,200 coulombs for one capacitor. Compare that to a AA NiMH battery that can deliver 7,200 coulombs. Not much power to start a car with. Where did I go wrong?
Where you go wrong is how fast it can deliver that charge. An AA battery can deliver about 1A. A capacitor, depending on it's structure, can deliver 100s of A. The total energy of the battery may be higher, but it cannot all be released in the second or two that it takes to start a car.

Bob
 

Herschel Peeler

Feb 21, 2016
401
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Feb 21, 2016
Messages
401
Where you go wrong is how fast it can deliver that charge. An AA battery can deliver about 1A. A capacitor, depending on it's structure, can deliver 100s of A. The total energy of the battery may be higher, but it cannot all be released in the second or two that it takes to start a car.

Bob

What you say is correct but the charge is still less. Caps may be great for triggering laser but for starting a car? I don't see it. Hundreds of Amps for a few seconds, not microseconds.
 
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