Date:         Wed, 10 Aug 2011 01:00:23 -0700
Reply-To:     Steve Williams <sbw@SBW.ORG>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Steve Williams <sbw@SBW.ORG>
Subject:      Follow-Up: Under-Sink Battery Installation
In-Reply-To:  <4E417B3A.2070302@gmail.com>
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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/

In that photo, it's showing the new house battery at about 11.2
volts, after a night and a day running the fridge and cabin light and
charging the laptop, followed by a 30-minute drive.

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.

The fridge and cabin light hardly register at all.  (I replace the
incandescent cabin light with a fluorescent tube.)

I cut the hole with a 2.25-inch hole saw.  I covered the paint front
and back with masking tape and cut a block of wood to back up the
face of the panel, then drilled from the back.  It didn't chew up the
paint too bad, at least on the front.

The screws are 6-32, so I drilled those holes with a #28 bit and
countersunk them as best I could in the tight space.

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.

The voltmeter is spliced into the gauge end of the shunt lead to read
the voltage from the battery side of the shunt.  I added a 22 gauge
ground wire for the voltmeter back to the ground block in the former
battery box.  That ground block and the shunt are tied to the battery
with 4 gauge cable, so it's just as if the voltmeter were tied
directly to the battery.

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.

I have the internal light kit for the gauge, but I couldn't find it
today.  I'll have to install it later, probably with a momentary
push-button switch so it's not on all the time.

This is the first time I've had the stove facia off.  A bit of a
pain.  Of course I was more than a little hesitant to drill a big
hole in it.  But I just clenched my teeth and did it.

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.  I think there is a significant
voltage drop from the starter battery up to the dash and over to the
fuse box under the steering wheel, then back to the house battery
through GoWesty's aux battery kit.  Probably some old, dirty
connections plus small wire sizes.

I wonder whether there's a way to run a big honkin' wire from the
starter battery over to the aux battery relay?

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?

It's nice to be able to really see what the house battery is doing in
detail.  I'm camped in a friend's driveway tonight, with the Westy
plugged into shore power, so the Pro-Sport charger is doing its thing
with the new house battery for the first time.  We'll see what the
voltmeter says after a proper full charge.

Here's a wide shot showing the whole stove, the Engel fridge, and bananas:

http://mira.sbw.org/photos/20110809/P1000400/