Replace your car battery with capacitors! 12V BoostPack

But I have my doubts...
you wanna look up something that does work?
Look up LiFe batteries. Lithium iron phosphate.
There are a number of brands, mostly sized for motorcycles.
Shorai, and Ballistic are two I have experience with.
I would think two of the physically largest ones wired in parallel would do it, and weigh less than 10lbs..
Of course you'd be $400+ in battery.
I'm currently running one in a '72 Honda 500 four, and one in a KTM 450 single.
The KTM will start cold on the button with it, when it wouldn't on the stock lead-acid battery that weighed 7lbs. , the LiFe weighs 20 ounces!
Oh, and they store great, 1% charge loss after sitting up to a year (claimed).