Hey, lighten up!!, we are talking about a disposable camera here (see 
the Subject). The cap  fits INSIDE the camera, it's the size of my 
pinkie! When was the last time you saw a 100 megaFarad cap, eh? - they 
probably have them lying around at Livermore lab.
and no, not milliFarads either - microFarads . So I'm an old f@rt! So go 
ahead, kick me around a bit. By the way, thanks for the correction 
(update), I'll try to be more careful in the future, (but the intent was 
to help folks repair batteries, not win a spelling bee). You could have 
left it at a simple units convention correction without getting nasty. 
Of course then you wouldn't have had all the fun of calculating how many 
fission bomb equivalents there are in a disposable camera.

This is a common practice for restoring NiCds. I have merely suggested a 
common source for a tool to restore NiCds - no need to be nasty.
By the way - it did work for me on a dead 9V Makita battery pack and 
some other stuff. And yes, you probably don't want to use this on a 
button cell.
And yes, you can get by with less voltage, but >100V is common - I had 
thought that 300V would be OK cause the cap is EVER so much smaller than 
my house.
And yes, it's true, you can use <100V but if you don't want to take the 
battery pack apart, I would guess that you need quite a bit more than 
the terminal voltage if only one cell is shorted.

I wonder though if someone who can't even spell ridiculous (you spelled 
it "rediculous" should be listened to at all about anything that he is 
ridiculing  :-)  I AM kidding here - wouldn't even have seen it, but my 
spell checker found it.

PLEASE forgive any gramme errors or misspellings on my part!
-- 

Looking forward,
Al Shinn


 >That's obviously absurd!

1/2 (300V)**2 * 100MF = 4.5TJ = about 1 kiloton of TNT equivalent, or a
large fleet of B-52s fully loaded with conventional bombs, or about 1/15 the
energy that leveled Hiroshima in 1945.

Assuming you really meant millifarads instead of megafarads (additionally
assuming "fd" was supposed to mean Farads), that's 4.5KJ unleashed on the
battery in a fraction of a second.  That's still rediculous when you
consider that's enough energy to launch a normal 5 pound clay brick 300 feet
into the air.

Don't try this at home folks.  This is messed up advice on a number of
fronts and could get you seriously hurt.  This guy can't even get basic
units right, so anything else he says is best disregarded.  You don't want
the equivalent of a 5 pound brick falling 300 feet onto your battery, and
you don't want to be nearby if you did try it.

Even with a lower capacitance, there is no need for 300V.  A NiCd cell is
only 1.2V.  The point is to produce a short current pulse to blow out the
little whiskers, or dendrites, while minimizing any other damage.  It
doesn't take 10s of amps to do this.  Ideally the damaging high voltage is
gone just as the dendrites fuse open.  That's tricky to arrange since the
amount and strength of the dendrites is unknown.  It's best to start at
5-10V on 1mF and work your way to higher energies until the dendrites blow.
Increase the energy by 2x each time, but 15-20V is max.  Use a higher
capacitance if you get that far and they're still not blown.  If 20V and
10mF doesn't work there is little point trying to salvage the battery.
 >


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