On another list devoted to light airplane electrical systems, there's been a
lot of discussion of "gel-cell" batteries.  It seems that although they are
still widely called gel cells, those have mostly been replaced by
recombinant gas technology.  These cells have a vent, but it is a safety
vent only, and doesn't emit anything unless the battery fails
catastrophically or is in a fire, in which case it releases pressure so the
case doesn't explode.

Check with the battery manufacturer, but it is probably sealed and won't
release any sort of gases unless it's failed, in which case you're going to
have to open the case and service the thing anyway.

I'd go with a little pack of silica gel unless I could ensure that it wasn't
being opened in the field, and I could assemble them in a known low-humidity
environment.

> -----Original Message-----
> From: jb [mailto:alphaone@ROF.NET]
> Sent: Sunday, January 20, 2002 12:05 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [ee]: Enclosed outdoor circuitry, moisture prevention
>
>
> I think silica gel will probably do the job - thanks for the
> info everyone.
> Roman, the case is a Pelican style, gray exterior, air-tight
> seal, no foam
> inside:
>
>         http://www.pelican-cases-flashlights.com/store/p3.html
>
> I too hope that the dissipation inside will not over do it,
> but we'll find
> out soon enough. It's not really a mission-critical thing
> (wireless AP for
> the use of myself and some friends) so I can experiment a
> little with the
> design. I'm now wondering if on hot days the gel-cell will
> emit fumes that
> are going to eat the circuitry.
>
> JB
>
> > -----Original Message-----
> > From: pic microcontroller discussion list
> > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Chris Loiacono
> > Sent: Sunday, January 20, 2002 11:06 AM
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: Re: [ee]: Enclosed outdoor circuitry, moisture prevention
> >
> >
> > It was once available from McMaster-Carr in large
> containers of small
> > packets.
> > I recently disposed of a couiple of hunderd pounds of the
> > stuff, too bad.
> > Realize you will need to replace the packets each time you
> > open the case for
> > more than a couple of minutes. The economics of it worked out
> > such that for
> > a handful of packets in a small assembly, it wasn't
> > worthwhile to bother
> > recharging them - cheaper to toss and replace. Just keep your
> > supply in a
> > good airtight environment.
> >
> > Chris
> >
> > On Fri, 20 Jan 102, JB wrote:
> >
> > > I suppose it might - if I can find a source for those
> > packets, I could
> > just
> > > stuff it in the available space. Is this the same
> substance that is
> > "recharged"
> > > by placing in the oven?
> > >
> > > >I'd say some silica gel would probably do wonders.
> > > >
> >
> > --
> > http://www.piclist.com#nomail Going offline? Don't AutoReply us!
> > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body
> >
> >
> >
>
> --
> http://www.piclist.com#nomail Going offline? Don't AutoReply us!
> email listserv@mitvma.mit.edu with SET PICList DIGEST in the body
>
>

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu