It's been a while since I did the math with these, so I was avoiding it. 100 amps for a second isn't much though. My 2.5L 4 cylinder Acura pulls 250+ amps peak, but cranks for about 2 seconds. Someday maybe I'll measure the voltage drop and calculate the energy consumption, but I still don't think going under 300F is reliable enough unless the battery can contribute something substantial.
As an aside, with my ~6 ft long run of 10 gauge wire to the glovebox, I'm unable to start my Acura with the LiFePO4 battery alone. It certainly needs the ultracap bank, though I haven't found out what the lower limit is for sizing purposes.
Looks like there are 120F caps for $6.90
https://www.mouser.com/ProductDetail...G33T0UjA%3D%3D
Why mess around with those when you can get 400F with low ESR for $11?
https://www.mouser.com/ProductDetail...yegxchbA%3D%3D
These are $11.69 for 150F, but you only need 5 since they are rated for 3v.
https://www.mouser.com/ProductDetail...g0qA9fIQ%3D%3D
Too bad nobody makes a 15v ultracap so you only need one.