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Topic: Super Capacitors as a Power Supply? (Read 4 times) previous topic - next topic

TchnclFl

Is it possible to use very large capacitors (super capacitors) as a power supply for small projects?  I know that capacitors are used to store charge, and can be utilized to slowly release their charge, but I don't get how :P.

This is the capacitor I had in mind:

http://www.cutedigi.com/product_info.php?cPath=260_272&products_id=4294&osCsid=ea443abf8844416c173225c297850c57

I had no immediate plans, but that's a pretty good deal for a large capacitor (1F!), and I thought I might as well get it if it could be used to power something small.

I was thinking something along the lines of using a solar cell to put in charge, and then it would continue to work without the sun during the night.  I chose capacitors because of all the problems with overcharging batteries (and I'm no expert), so I don't want things to explode.. :P

Thanks!

Osgeld

Quote

I chose capacitors because of all the problems with overcharging batteries (and I'm no expert), so I don't want things to explode..


overcharging a cap will make it explode just as quick, if not quicker, its not a way out of making a proper charging circuit

retrolefty

Not really possible to use 'super caps' as a power supply for anything but very very small current loads. One big disadvantage is that as you draw current from a cap it's output voltage decreases linearly rather then a near constant voltage as a battery supplies. If you can estimate the current load you have in mind then one can do some math and see if it's possible.

Super caps as a power source have very limited applications. I've seen them used to supply standby voltage for volatile SRAM type memory chips, and stand-by power for real time clocks, etc but other then that they are really limited.

Lefty

TchnclFl

Alright, well, like I said, I'm no expert :P.

Thanks for the responses.  I'm seeing that it really wouldn't be practical.

I did not know that the voltage drops, the real reason it wouldn't work for me :P.

Thanks for the help! :D

Ran Talbott

Mouser has specs (PDF) on these on their site.

That particular cap is supposed to supply 1.5mA for half an hour.  Good for keeping your real-time clock chip running while you change batteries,  but not even good enough to maintain it during some power outages.

I suspect that they might be good for dramatically upstaging this guy,  if you can borrow a high-speed camera,  though   ;D

Ran

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