Capacitor based power supply

I know little about circuit design, but can build them. Maybe this would be a good challenge for someone.

What I need is a power supply circuit with a 12 volt output that will run a laptop for several (many ?) hours off of any reasonable number of large (liter or so size) capacitors. The reason is that I need a power supply that recharges very quickly and is easy to carry by hand on mountain trails to get it charged - assuming such a power supply would be light enough (40 pounds or less) to be portable. Additional circuits running off the 12 v. circuit to supply both 5 v. and 3.7 v., both at 500 miliamperes would be nice too, though I could probably find those somewhere to easily incorporate.

I know the dangers of large capacitors and can deal with that with a plastic box. I'm a practicing coward, and am not about to short myself across the leads

Can somebody help? If you put a solution here, email me at:

patiakaladurga@gmail.co.in

and I can come out of the mountains here in India and check the site. Emailing the circuit diagram will not work, as the email is retrieved over a cell phone.

Thanks ! !

Sorry, but silly idea!.

Capacitors of similar capacity to a battery would take just as long to charge, and would be a great many times the size of the battery.

40 pounds? If your weight limit is that high you could carry a couple sealed lead acid battery and build a high current DC-DC converter. Like Nigel said, capacitors are just not a good idea, their power density is absolutly horrible, something that would power a laptop for any decent amount of time would be the size of a small car.

pound for pound, batteries still put capacitors to shame.

If your weight limit is that high, and you really need instant charge capabilities might i suggest a portable generator? very small ones might fit in you weight limit and provide even more power density (when you include fuel) than batteries. "charging" a generator is as fast as pouring more fuel into it.

Apparently there is a mfg out there that makes a flexible solar panel stitched to a backpack for charging batteries on hikes. Seems like a much better way to go.

bryan, could you provide a link? It's really mean to say someone out there makes something without providing a link.

Just search solar panel backback on google.

I think this is the one I stumbled on before

**broken link removed**