Question: capacitors as special use batteries?

[msadkins04@yahoo.com]

I recall from my hobbyist days that high-voltage capacitors can keep a
charge for a significant amount of time, especially if they are cut-
off from the circuit subsequent to charging.

I'd like to know whether it might be feasible, from a technical and
cost-effectiveness standpoint, to use a large array of specially
designed capacitors to hold excess electricity from solar plants for,
say, periods of a week or more. This would be helpful to bridge gaps
caused by overcast weather, and for other purposes.

I know that there are potentially problems with dielectric breakdown
and leakage. On the plus side, such "batteries" could be charged and
discharged very quickly, as needed, and without the complications
involved in conventional batteries using chemical electrolytes.

 

[JeffM]

msadkins04@ yahoo.com wrote:

I'd like to know whether it might be feasible, from a technical and
cost-effectiveness standpoint, to use a large array of specially
designed capacitors to hold excess electricity from solar plants for,
say, periods of a week or more.

This seems like a question for sci.electronics.misc
or even sci.electronics.basics.

The tiniest bit of research on your part would have revealed
that batteries are better for this:
http://www.google.com/images?q=capacitor+discharge-curve
http://www.google.com/images?q=rechargeable+discharge-curve

 

[Franc Zabkar]

On Wed, 9 Jul 2008 10:31:15 -0700 (PDT), "msadkins04@yahoo.com"
<msadkins04@yahoo.com> put finger to keyboard and composed:

I recall from my hobbyist days that high-voltage capacitors can keep a
charge for a significant amount of time, especially if they are cut-
off from the circuit subsequent to charging.

I'd like to know whether it might be feasible, from a technical and
cost-effectiveness standpoint, to use a large array of specially
designed capacitors to hold excess electricity from solar plants for,
say, periods of a week or more. This would be helpful to bridge gaps
caused by overcast weather, and for other purposes.

I know that there are potentially problems with dielectric breakdown
and leakage. On the plus side, such "batteries" could be charged and
discharged very quickly, as needed, and without the complications
involved in conventional batteries using chemical electrolytes.

http://en.wikipedia.org/wiki/Supercapacitor

UltraCapacitor powered tool:
http://www.colemanflashcellscrewdriver.com/

UltraBattery powered hybrid car:
http://www.technologyreview.com/read_article.aspx?ch=specialsections&sc=batteries&id=20105&a=

"The so-called UltraBattery combines 150-year-old lead-acid technology
with supercapacitors ..."

- Franc Zabkar
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