battery / capacitors

[exxos]

Hi all,

Roughly how many farads would be needed to replace say a simple 1.5V AA
sized battery ? with a similar run time..

thanks,

Chris

 

[Fred Bloggs]

exxos <exxos@home.co.uk> responded in
news:3f92dd4e$0$6621$cc9e4d1f@news.dial.pipex.com like this:

Hi all,

Roughly how many farads would be needed to replace say a simple 1.5V AA
sized battery ? with a similar run time..

C = IT/V

So for 2000mAH, Vmin 1V, C = 2 x 60 x 60 / 0.5 = 14.4kF.

--
Fred Bloggs.

 

[Watson A.Name - "Watt Sun]

In article <3f92dd4e$0$6621$cc9e4d1f@news.dial.pipex.com>,
exxos@home.co.uk mentioned...

Hi all,

Roughly how many farads would be needed to replace say a simple 1.5V AA
sized battery ? with a similar run time..

It's not the same. A battery's voltage stays relatively constant,
whereas the capacitor continually discharges, to zero. But you'd need
lotsa farads. See http://www.maxwell.com/ultracapacitors/

thanks,

Chris

--
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[exxos]

"Fred Bloggs" <me@privacy.net> wrote in message
news:Xns9419CCE13731SpecialIdString@130.133.1.4...

exxos <exxos@home.co.uk> responded in
news:3f92dd4e$0$6621$cc9e4d1f@news.dial.pipex.com like this:

Hi all,

Roughly how many farads would be needed to replace say a simple 1.5V AA
sized battery ? with a similar run time..

C = IT/V

So for 2000mAH, Vmin 1V, C = 2 x 60 x 60 / 0.5 = 14.4kF.

--
Fred Bloggs.

Ah, I did it for a guess at 100ma for a hour and got 400F, in other words
BFC!

Chrsi

 

[Watson A.Name - "Watt Sun]

In article <3f92fe83$0$9466$cc9e4d1f@news.dial.pipex.com>,
exxos@home.co.uk mentioned...

"Fred Bloggs" <me@privacy.net> wrote in message
news:Xns9419CCE13731SpecialIdString@130.133.1.4...
exxos <exxos@home.co.uk> responded in
news:3f92dd4e$0$6621$cc9e4d1f@news.dial.pipex.com like this:

Hi all,

Roughly how many farads would be needed to replace say a simple 1.5V AA
sized battery ? with a similar run time..

C = IT/V

So for 2000mAH, Vmin 1V, C = 2 x 60 x 60 / 0.5 = 14.4kF.

--
Fred Bloggs.

Ah, I did it for a guess at 100ma for a hour and got 400F, in other words
BFC!

Maybe not so big, physically.
http://www.maxwell.com/ultracapacitors/products/large_cell.html

Chrsi

--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

 

[Ross Mac]

Why don't you get one of those 5volt 1 farad caps. They are about the size
of 4 quarters stacked up. We used to use them to keep the old DRAM energized
without batteries. They would last months and months. I think the last one I
bought was from http://www.altronics.com in northern California...
Good luck and take care, Ross


"exxos" <exxos@home.co.uk> wrote in message
news:3f92dd4e$0$6621$cc9e4d1f@news.dial.pipex.com...

Hi all,

Roughly how many farads would be needed to replace say a simple 1.5V AA
sized battery ? with a similar run time..

thanks,

Chris

 

[exxos]

"Watson A.Name - Watt Sun" <alondra101@hotmail.com> wrote in message
news:MPG.19fcadf1f517d33e9897ec@news.dslextreme.com...

In article <3f92fe83$0$9466$cc9e4d1f@news.dial.pipex.com>,
exxos@home.co.uk mentioned...

"Fred Bloggs" <me@privacy.net> wrote in message
news:Xns9419CCE13731SpecialIdString@130.133.1.4...
exxos <exxos@home.co.uk> responded in
news:3f92dd4e$0$6621$cc9e4d1f@news.dial.pipex.com like this:

Hi all,

Roughly how many farads would be needed to replace say a simple 1.5V
AA
sized battery ? with a similar run time..

C = IT/V

So for 2000mAH, Vmin 1V, C = 2 x 60 x 60 / 0.5 = 14.4kF.

--
Fred Bloggs.

Ah, I did it for a guess at 100ma for a hour and got 400F, in other
words
BFC!

Maybe not so big, physically.
http://www.maxwell.com/ultracapacitors/products/large_cell.html

Chrsi

wow, would be interesting to see what happens to the steel rule after
shorting one of those out ;-)


chris