Date: Wed, 5 Aug 2009 17:15:19 -0700
Reply-To: mark drillock <mdrillock@COX.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: mark drillock <mdrillock@COX.NET>
Subject: Re: Vitrifrigo trip results, wiring, battery life,
charging issues, etc
In-Reply-To: <C68D0AE9-C115-425F-9206-BEC606D6BCCF@VICKERSDESIGN.COM>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
In my case the lesson is that there is an existing weakness in my old
charging path that I should fix. I have an engine conversion that was
done 10+ years ago. The wiring splice done back then to the charging
path is probably degraded and simply renewing it would solve my charging
issues. Running an additional wire like I did bypasses the likely flaw.
You can run a charging wire from the alternator right to the separator
device to minimize wire length and get a more consistent charging rate
independent of the loads on the main battery. UNLESS you plan to be able
to use the aux battery for starting assist. That feature should not be
implemented unless there is large wire connecting the 2 batteries to
each other or the starter over the entire path. My preference would then
be to have a somewhat larger charging wire from the alternator to the
starter and then an even larger wire from there to the separator under
the back seat and on to the aux battery. Since there is a huge stock
wire from the main battery to the starter, use the starter as the place
to connect the aux battery too, with a large enough wire to handle
starting current. This would safely let both batteries supply starting
current if desired. Then the wire from the alternator to the starter
would not see any current flow due to starting, other than what the
fuel/injection system needs. After the engine starts the alternator
provides the power for the fuel/injection system and also to the starter
post where the batteries tie in for charging.
One concern is whether the big wiring allows the batteries to draw too
much from the alternator. Long and small wires act can as a safety
device that limits the current flow to the batteries. I know this may
seem like a strange concept but it is true. Short small wires can be
dangerous in high current situations but a balance between size and
length can be reached that will allow the battery to get only so much of
the alternator output. The trick is to find that balance area while
getting the most charging that the alternator can safely provide.
Mark
Jeffrey Vickers wrote:
> So the moral of the story is: run a big charge wire to your setup. In my
> case, since my aux battery and 1315 are under my rear seat, would it
> make more sense to run that bigger charge wire straight to the main side
> of the 1315 instead of going all the way to the main battery? Shorter
> wire, less drop etc...
>
> Jeff
>
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