Date: Wed, 10 Aug 2011 07:48:15 -0700
Reply-To: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Rocket J Squirrel <camping.elliott@GMAIL.COM>
Subject: Re: Follow-Up: Under-Sink Battery Installation
In-Reply-To: <201108100800.p7A80VS96799@sbw.org>
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On 08/10/2011 01:00 AM, Steve Williams wrote:
> Tuesday I dove back in and completed another piece of my house
> battery project. I installed an aviation gauge in the stove facia,
> an expanded-scale voltmeter and -30/+30 amp meter in one instrument:
>
> http://mira.sbw.org/photos/20110809/P1000402a/
I love it. It looks highly technical.
<snip>
> The ammeter shows a roughly 4-amp discharge. That's mostly the
> laptop charger. What you can't see is that the laptop charger causes
> the ammeter to oscillate about +/- 1 amp maybe once a second. Odd,
> but it doesn't seem to hurt anything.
I reckon it's just the way your laptop draws power. I can't see any
reason why a varying load would bother your van's aux power system.
> The fridge and cabin light hardly register at all. (I replace the
> incandescent cabin light with a fluorescent tube.)
A 30-0-30 amp scale is not going to show your typical small loads. I use
a 10-0-10 amp meter for that reason. I am surprised that you cannot see
the refrigerator, though. Norcolds and Vitrifrigos draw nearly 3 amps
when running and that should be visible. What is the current consumption
spec for your Engle reefer?
<snip>
> The wires from the shunt are 20 gauge. They came with the
> gauge. Surprisingly, those wires are not fused. I bought a fusible
> link kit from B&C Specialty Products, but I haven't put it together yet.
My aux battery monitor's ammeter shunt is connected between the battery
- terminal and van frame, so no fusing is needed. I'd like to see the
documentation for your unit, if the ammeter portion of the meter has its
own two dedicated wires for connecting to the shunt you may want to move
it to the ground leg.
>
> The voltmeter is powered at all times. I welcome your comments on
> whether it should be switched. I can't imagine it draws more than a
> few milliamps.
That's going to be difficult for anyone to answer without a link to the
specs for the meter.
<snip>
> Here is the gauge with the engine running:
>
> http://mira.sbw.org/photos/20110809/P1000404/
>
> It shows the alternator dumping about 9 amps into the battery. The
> voltage is relatively low, about 12.3 volts. That's a little
> disappointing, because I know the alternator is making over 14 volts
> at the post of the starter battery.
Yeah, you'll never get a full charge into the aux battery with voltage
that low. But have you checked the accuracy of the new voltmeter by
sticking a good voltmeter across the aux battery's terminals?
> I wonder whether there's a way to run a big honkin' wire from the
> starter battery over to the aux battery relay?
I did, so yes.
> Is it possible to drill holes and fish wires through the low raised
> floor between the front seats? Or is that space open to the
> street? Or have shift linkages in it?
Uh . . . it's been years and I forget how it was routed, but it wasn't
too tough as I recall.
<snip>
>
> Here's a wide shot showing the whole stove, the Engel fridge, and bananas:
>
> http://mira.sbw.org/photos/20110809/P1000400/
As long as you got bananas, you are fine.
--
Jack "Rocket j Squirrel" Elliott
Bend, Ore.
1984 Westfalia. A poor but proud people.
1971 "Ladybug"-brand utility trailer ca. 1972 from a defunct company in
San Clemente, Calif., now repurposed as The Westrailia.
