Date: Mon, 6 Aug 2007 14:27:51 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Deep cycle batteries, voltage regulators, and eating cake
In-Reply-To: <vanagon%2007080613591391@GERRY.VANAGON.COM>
Content-Type: text/plain; format=flowed
What you need to do is find out where the voltage is being lost and is the
alternator working properly? Properly, at any speed above idle the
alternaotr should be maintaining approxiamtley 13.8 volts. Under light load,
there is little trouble maintaining that voltage even at idle. So to find
the loss strt as follows:
With enigne running measure voltage between the alternaotr output terminal
and the alternator case itself. Make sure you have good contact. Clean
through the paint rust, scale etc.
13.5 to 14.0 volts there? OKay, that is good.
Move the negative lead from the alternator case to vheicle chassis. Same
reading? Yes, good, no you have a ground problem. The loss can be from the
alternaot to the bracket or to the case or the case ground straps or some
combination. Time for separate ground from alternator to chassis.
Next step is the wirng from the alternator to the batteries, fuse box and
other power ditstribution. Here most of the Vanagon woring is lacking
incapacity. Add all these years of wire and terminal oxidation and you got a
real bad case of the IR drop blues.
There are many paths to upgrade the wiring. Here are some simple
suggestions.
Add another feed from the alternaotr to the batter cable at the back of the
starter. #6 is a good start that is still easy to work with.
If you have an 87 and later woth AC, there are 2 wires going from the
battery cable. One goes to the fuse box as the main feed, the other goes to
the high speed radiator fan relay. Run a jumper form the feed side of the
big fuse down to the fuse box. This will make ahigh difference. You can also
run another wire from the alternator instead.
For the auxillary battery, use a new feed from the alternator. Now you have
full alternaotr output available for the battery and accesories on that
line.
This will take care of most of yur charging and dim light problems.
Dennis
>From: Geza Polony <gezapolony@SBCGLOBAL.NET>
>Reply-To: Geza Polony <gezapolony@SBCGLOBAL.NET>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Deep cycle batteries, voltage regulators, and eating cake
>Date: Mon, 6 Aug 2007 13:54:13 -0400
>
>Here's another wrinkle in the whole equation (to mix a metaphor): the
>voltage regulator/alternator system doesn't seem to be adequate to keep the
>batteries charged.
>
>Under load (fridge, AC, headlights, etc. on) my system barely generates
>12.3
>volts at the vehicle battery, and about 11.8 at the aux battery. This is
>with a rebuilt alternator and new vehicle battery (a week old on both.)
>With
>no load, voltage is normal, about 13.8- 14 volts.
>
>In other words, there's not enough voltage to charge the batteries, no
>matter how you configure them, while driving.
>
>Those of you who have experimented with variable voltage regulators, what
>have your results been? There seems to be consensus that Bosch regulators
>are "lazy" when it comes to dealing with load, and that's what I'm seeing.
>
>If you're using a battery charger on the bench (or bedroom floor) to test a
>system, it doesn't seem like you'd get the same results as in the real
>world, where your alternator is trying to power umpteen things and charge
>two batteries at the same time.
>
>Maybe we could eat that cake at a free lunch, to mix another metaphor.