[Coco] Survey of Coco realtime clock users

[Arthur Flexser]

On Fri, 30 Nov 2007, Gene Heskett wrote:

> On Friday 30 November 2007, Robert Gault wrote:
> >Arthur Flexser wrote:
> >> Out of curiosity, how'd you go about replacing the battery?  It looked
> >> like the battery was potted in epoxy or something and not at all easy to
> >> replace.  On the other hand, it was rated to last 10 years.  How long did
> >> yours hold out for?  I never heard of a case of one finally giving out.
> >>
> >> Art
> >
> >Not sure exactly when I bought it but a expect at least 10 years ago.
> >
> >Right the battery is potted and I doubt it would be safe to try to
> >remove the epoxy. I measured the voltage on the exposed DS1216 leads and
> >found several with about 1vDC. The battery is a lithium and should be
> >about 3vDC.
> >
> >Marty Goodman posted some suggestions on replacing the battery but I'm
> >not sure he actually did it. While one should remove the battery from
> >the circuit, I decided placing a new one in parallel would be sufficient.
> >
> >Radio Shack has all lithium batteries at the same price so I bought the
> >largest one, about 5 to 6 times larger than the one in the Smartwatch.
> >Should last 50-60 years :)  Solder connected it to DS1216 pin4 +v and
> >pin8 ground. Pre-tested this with two dry cells in series.
> >
> >Works great!
> >
> But that is probably a recharger for the internal lithium cell, and a larger 
> version of one of those just exploded in Korea, fatally breaking the ribs and 
> spine of the man who had it in his shirt pocket.  Those button cells are NOT 
> designed to be recharged, ever.
> 

So that epoxy DOES have a function, after all!  It's a safety feature to contain
the explosion!  (Or perhaps an anti-safety feature to create more shrapnel when
it goes off?)  ;-)

Art