[sdiy] several questions

[Happy Harry]

Yep. Sometimes little whiskers of nickel grow through the paper
containing the electrolyte... causing a short. They are fairly high 
resistance but will prevent the battery from charging... or self discharge 
it.

The cap and SCR throw such a high current pulse into the cell that the
whisker gets vaporized and the time is so short that the cell doesn't
get hot or explode.

This same technique can be used on printed circuit boards and wiring
harnesses in some cases. Remove all chips you can first... then
ZAP !!!

H^) harry


>From: CHoaglin at aol.com
>To: harrybissell at prodigy.net, mtman at cloud9.net
>CC: synth-diy at node12b53.a2000.nl
>Subject: Re: [sdiy] several questions
>Date: Tue, 1 May 2001 12:35:00 EDT
>
>In a message dated 4/30/01 8:34:12 PM Pacific Daylight Time,
>harrybissell at prodigy.net writes:
>
><< Lithium Batteries have an wonderful hidden "feature"... the depleted
>  sections of the battery turn into very good conductors... causing little
>  drop
>  for the remainder of the voltage. A meter will NOT tell you the charge
>  remaining... they will stay 3V until a swift and possibly untimely death.
>   >>
>
>So THAT's why they always measure 3V or nothing..I'd been wondering about
>that for a while. While we're on batteries, I've seen an interesting
>technique used by my uncle to give NiCd packs a new lease on life, namely
>using a large cap and and SCR to discharge the cap through the
>battery..Something about "blowing the shorts out of it"...anybody know
>anything about this?
>
>Chris

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