Date: Mon, 17 May 2004 21:18:45 -0700
Reply-To: Rob Campbell <rob@PHEMP.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Rob Campbell <rob@PHEMP.COM>
Subject: Battery isolator trouble
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hello-
A while back I installed an auxillary battery and a surepower isolator.
I thought all was well for a while, but its not. The batteries arent
charging.
Alternator is putting out 13.8... which sounds normal. With engine on,
the batteries are reading about 11.9-13.2, depending. Same reading on
the respective isolator terminals. The "Alternator" terminal on
isolator reads as high as 13.95, and the "regulator" terminal reads as
high as 14.07, but the surepower manual says it should be 14.8 to 15.5
to account for the voltage drop across the isolator diodes.
Recently my alternator light has been coming on. At times it just
remains on after starting engine, and at times it comes on after driving
a while. The starting battery is not being recharged, its now at 12.3
volts (engine off for a while).
I stumped my first mechanic; he said "it looks good, its fine" but I
wasn't aggressive enough with him I suppose. When I got home to my
multimeter and measured things, it didn't look "fine".
I then visited another mechanic, he found that the regulator tab was
perhaps not bent correctly, and again I drove away thinking all was
well. The alternator light came on shortly after leaving, and the
batteries were reading lower than ever when I got home.
Today I checked the regulator again, and more thoroughly bent the
alternator tab (which is actually inside the alternator) to prevent
connection with the regulator.
The 2nd mechanic is too busy at the moment to take a look, but I need
this problem corrected very soon.
So anyone else have ideas for what I can check out? Or, anyone know a
good VW/electrical talent in Seattle area? I'm considering contacting
RV shops which have experience with isolators, but maybe not with Bosch
alternators. As my first mechanic showed, not all VW mechanics are very
familiar with this setup.
It looked pretty straight forward to me, but I am now stumped. I've
tried to verify grounds (using continuity test), I've rechecked the
connections according to the Surepower diagrams, I don't know what else
I can do.
If it helps: main battery is brand new Sears International, aux is
Optima Yellowtop, isolator is Surepower 1202R (i think... its the Bosch
flavor at any rate)
Thanks
Rob Campbell
87 Westy, Seattle
