storing power in huge HUGE capacitors?

[Nostahl]

My buddy has 4 or 5 HUGE capacitors i cant remember the stats on them though but they are about the thickness of your forearm and about as long. bolts for contacts.

any one know how much these can store?

i dont know much at all about power systems and what not.
is there any reasons to use these for storage devices or any reasons not too?
all i need to power is a 2 or 3 12v florescent lights and a 12v laptop that draws 32 watts.

I guess my question is. can these be used to store power and power my devices similar to using  a bank of golfcart batteries?

[ghurd]

I doubt it.
1 Farad is a huge value.  That's why most caps are rated in micro Farads (uF).
The capacity looks impressive, until you realize that is the TOTAL capacity, and the only useful power is between about 14.8V and 12V.
With 1F cap (1,000,000uF), and those loads, I get the running time at roughly 1.25 seconds.
G-

[Nostahl]

ah ok.
 problem solved then.

[dnix71]

Not only is the total power limited, you have to be careful around caps that big. They can dump their entire load pretty quick.

http://www.youtube.com/watch?v=9jDsNe_bmtE&NR=1&feature=fvwp   this mad scientist put 15v on 10v caps and filmed it at 300FPS.

[ghurd]

Videos!  
I did this a couple days ago related to something else, but maybe it is relevant.
The intent was to prove the cap charged by short bursts of charging at a low duty cycle could power the fan.

15,000uF cap, affectionately referred to as a 'beer can cap',
25V battery (12.6V + 12.4V),
24V 140ma fan, which runs on proportionally less amps as the voltage is reduced.
I figure it will operate down to slightly below 10V at about 50ma.

Together, that means a far wider operating voltage, and a very small load, on an arguably 'huge' cap.
It works, but barely.  Suitable for the intended purpose.  Not suitable for normal loads.

http://s701.photobucket.com/albums/ww20/ghurd1/Stray%20Pics/?action=view&current=PICT1355.flv

I'd have done a better job with the video if I knew I'd post a link!
G-
(Edit-  That is a 15,000 uF cap)

[frepdx]

I guess my question is. can these be used to store power and power my devices similar to using a bank of golfcart batteries?

probably not. Capacitive storage is possible but it's pretty expensive. You need special capacitors and a lot of control electronics since the capacitor voltage changes with the energy stored, much more so than batteries.

Here's an example http://www.oshkoshcorporation.com/about/tech_innovations~propulse.cfm. I think it uses Maxwell capacitor banks. http://www.maxwell.com/ultracapacitors/products/index.asp

[isoutar]

The proper way to use ultra capacitors ...

You need to use a switching power supply ideally to use capacitors as a power supply.     With the appropriate step up switching power supply you can maintain a 12 volt value until the cap discharges below about 3-4  volts.   This gives you a power supply that is more useful.   

Here is a link to Maxwell ... one of the big ultra capacitor suppliers.   You can see that they are marketing wind and solar applications.   Not sure where they are located in the world.   The University of Victoria uses Maxwell ultra caps for electric vehicle research.

http://www.maxwell.com

Ian

[cylindar]

http://www.goodideacreative.com/solar_supercaps.html should have what your are looking for.

[bob g]

that youtube electrolytic brought back some memories

about 40 years ago, while breadboarding, i had an electrolytic 10volt about the size of my thumb laying on my thigh, with jumper/alligators
and was pulsing a relay with about 13 volts, holy wow!!!

thank god i had on a pair of levi's, not sure if my leg would have done as well as it did had i been wearing something lighter.

left a huge red mark on my leg and really rang the crap out of my ears.

i can't imagine a cap the size of my arm being misapplied, the results likely could be deadly

even a vented one would likely burn the living crap out of you if you are anywhere close to it.

bob g

[admin]

Capacitor = low energy density.
Not even a player in the energy storage biz yet, at least not for homes.
ADMIN

[Bushwhacker]

Geez you guys! I have a 7700uf 200V cap kicking around and now I want to blow it up... just for kicks??? A beer can is 355 ml this cap would be right around the 425 ml mark for volume. HMMMMmmm? [insert evil grin here]

[frackers]

Geez you guys! I have a 7700uf 200V cap kicking around and now I want to blow it up

Dunno that I would recommend it. Of several exploding caps I've experienced my favourite was a 32uF 350v specimen that inadvertently got 450v on it. It was on the underside of an aluminium chassis that was sitting on top of radio in the 'shack'. A large bang and a line of paper and foil 2 inches wide appeared round the walls of the shack 3 feet off the ground, and across my girlfriends hair lined up with the top of the radio and the bottom of the chassis - she was not impressed!

I *WAS* impressed by the force that that ripped out 4 pop rivets from end wall of the chassis, straightened the 16swg ali out flat, and left a dent in the timber wall at the end of the bench. That can of the cap I didn't find for a couple of weeks - it had rebounded back under the table this gear was on and buried itself 6 inches into a rolled up carpet.

No surprise that particular relationship didn't last long

[Bruce S]

frackers;
I'm with you on this one. I want NO part in helping someone with possibly ending their visit on this planet

bushwacker: NOT a good idea!!

[TomW]

frackers;
I'm with you on this one. I want NO part in helping someone with possibly ending their visit on this planet

bushwacker: NOT a good idea!!

And, possibly winning a Darwin Award! 

Tom

[ruddycrazy]

For a laugh last year I stuck a tantalum cap down an ant hole and man it must of gone down about 4', the wire run was about 30' and when I reverse powered it I saw smoke coming out of holes all over the place ( well a decent radius). For a while the ants nest was barren and I reckon the ants were pretty peeved off. I have recently de-soldered a heap more off old boards so it might be time to give the ants another headache.......

[Norm]

I'm not sure this might also be dangerous to the novice but sounds as
an ultra capacitor might work...he says that it will run a small device for about a
minute.
http://www.los-gatos.ca.us/davidbu/pedgen/ultimate_pedal_tv.html
seems to explain most of it.....
.....still it could be dangerous
no matter what even a seemingly expert should always read the
disclaimers?
Norm.

[Bushwhacker]

Rest assured this 'just for fun experiment would involve plenty of wire, a very save viewing area (shack?) with a Lexan window to look out of.

I know a guy who blew his hand off with dynamite when he was a kid and think I'm just a bit brighter than that. I have worked with explosives for a living and have a great deal of respect for any explosion. Mind you seeing a refrigerator 75 ft in the air is quite entertaining. (we were disposing of unusable explosives)

That said I have done some silly stuff in my day but it usually involved an internal combustion engine and wondering if 'something' crazy could be done. 

frackers;
I'm with you on this one. I want NO part in helping someone with possibly ending their visit on this planet

bushwacker: NOT a good idea!!

And, possibly winning a Darwin Award! 

Tom