Date:         Mon, 28 Jan 2013 21:31:07 -0500
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: Electrical Gremlin of Jan 18 has been detected
Comments: To: Richard Koller <kollerr@HELIX.NIH.GOV>
In-Reply-To:  <011b01cdfd92$5fdddb00$1f999100$@helix.nih.gov>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 03:02 PM 1/28/2013, Richard Koller wrote:
>function is supposed to work only with the engine running. When I popped the
>12 volt switch off, the ammeter now read about 50ma and there was no more
>clicking sound. I presume this must be  a sticky  relay for the fridge that
>is under the driver's seat.

Good ears!

Sounds like a PO maybe added a relay to take load off the DC switch
and wired it to the kitchen circuit instead of the fridge circuit
(kitchen is 8 A always live, fridge is 16 A live when alternator
working; both located bottom of driver's B pillar inside a little black box).

The relay under the seat doesn't know or care whether the fridge DC
switch is on, it operates when the alternator starts charging regardless.

Incidentally, 200 mA for 48 hours is 9.6 amp-hours, so if that's
killing the battery you maybe should look into battery condition.

And I should have mentioned before that it's considered the genteel
thing to do to make your final ammeter connection away from the
battery, for the same reason that when jump starting the last ground
connection is made to a ground on the receiving vehicle somewhere
away from the battery -- just on the off chance that a little
hydrogen is nearby, you'd rather not tempt it with a spark.  I used
to think this was a bit prissy, until I became acquainted with two
people who'd had batteries blow up in their faces (not frozen, not
being fast-charged, not hooked up backwards to jump-start).  Neither
was much hurt -- one heard it rumbling and left in a hurry, and the
other had a garage-full of people shove him under a hosepipe right
then.  But they said they'd just as soon not repeat the experience.

I ran across a table of upper and lower explosive limits for various
gases.  The wide range (4-75% by volume) of hydrogen didn't surprise
me, but some of the others did.
http://www.mathesongas.com/pdfs/products/Lower-(LEL)-&-Upper-(UEL)-Explosive-Limits-.pdf

Yours,
David