Capacitor "packs" as a replacement for lead acid type batteries for engine starting.

[Tirediron]

The trucking and construction industries have been using engine start modules for a few years with pretty good results, basically a capacitor group to replace one of the group 31 batteries in a class 8 truck/ tractor .
A guy on you tube has done a fair bit of experimentation and shows interesting results.
laserhacker.com should take you to his site, and then look at the playlists if this is of interest. I think that this might be a pretty handy thing to have especially since they get more efficient in the cold weather.

 

[Peanut]

I think its a great idea. I've worked with some large caps so they certainly have the power, just build a bleeder circuit.. The problem with building one is the availability of the right kinds of parts. All sorts of supply chain problems going on these days.

If you want to speak to someone with lots of experience working with capacitors call up the folks at Arnonld AFB in TN. They have an EMP simulator there. It's said the bank of caps they use is 6 stories high.