Date: Fri, 21 Aug 1998 08:41:02 -0800
Reply-To: YauMan Chan <YauMan@CCHEM.BERKELEY.EDU>
Sender: Vanagon Mailing List <Vanagon@vanagon.com>
From: YauMan Chan <YauMan@CCHEM.BERKELEY.EDU>
Subject: WIERD SCIENCE -Reply
Content-Type: text/plain
Mark,
It all points to a resistive drop across the power buss. There
are two possibilities I could think of:
1. Check the grounding point. Since you moved the battery,
your battery's negative terminal is now probably grounded to
a different part of the van. That part of the van where you
bolted the gound may not have a low resistance to the rest of
the van and to the ground of the alternator etc. Try using a
different grounding point. The ground point of the battery
much have a ZERO resistance to the ground point of the
alternator. The floor pan of the van or any cars for that
matter is not usually a good ground. Trying running a ground
strap from the battery's negative terminal directly to the
engine ground (like the alternator mounting bracket. Or run a
grond strap from the alternator to the floor pan of the van.
So-so grounding paths usually shows up when the electrical
system is under load.
2. #6 awg wire may not be thick enough to carry the
amparage required if the wire is longer than 4 or 5 feet. You
should try a #2 or even #0 awg wire. (Resistance is directly
proportional to the length of the wire and inversely
proportional to the cross section area.) Touch the wire
immediately after you start the van. It it feel warm, even
slight, it is now thick enough!
Yau-Man Chan
87 GL
>>> Mark Thoma <TVReporter@STRATOS.NET> 08/20/98
04:23pm >>>
Hey Everybody,
There must be some kind of weird alternator bug going
around. Mine is acting very strange.
I recently moved the battery from the engine compartment to
under the rear seat. New heavy gauge battery cables, new
battery, new belts etc. Suddenly the new voltmeter on the
dash starts giving strange readings. When the van starts, I
get 10 volts, after it comes off idle, it will come up to 12
slowly, then after a few seconds of higher rpm it will come up
to 14 volts slowly. If I turn the lights on down to 13 volts. If I
turn the heater fan on down to 12 volts or lower. Obviously if
I hit anything else even lower. Thinking I had a bad
alternator, I replaced the 65 amp model with a 90 amp
Quantum alternator. Same symptoms. Thinking that maybe
the primary lead from the alternator to the battery was too
small for the job I bought some 6 guage multi-strand (1/4
inch in diamter) and soldered on some heavy copper lug
terminals. Same symptoms. The battery has a good ground
to the body, as does the alternator, and the engine itself. Oh
by the way, it's not just the gauge. When I turn on the lights
at night, and then turn on the heater fan the lights dim
noticably. I think with a 90 amp alternator I ought to be able
to power all the lights and heater fans I want and still have
juice to spare. And one last thing, the local parts store
tested both alternators and their machine said they were
operating just fine.
ANY IDEAS?
Mark Thoma
'82 intercooled turbodiesel Vanagon
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