Date: Tue, 14 Apr 2009 19:43:34 -0400
Reply-To: pickle vanagon <greenvanagon@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: pickle vanagon <greenvanagon@GMAIL.COM>
Subject: Electrical setup: Photos and details
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I wanted to send an update on the big electrical project that I undertook.
My goal was to make the AC/DC systems work together like they "should", so
that the battery can power the A/C outlets via an inverter when no shore
power is available, and the shore power can charge the batteries and run the
DC system when shore power is available.
For AC->DC conversion, I settled on the Truecharge 10tb:
http://www.xantrex.com/web/id/185/p/1/pt/7/product.asp
I chose it because:
*) It is a true multistage charger, capable of delivering 10 amps (in total,
but it can deliver all of them to either battery).
*) With 10 amps, it can charge the system pretty fast, and if at some point
in the future I need to garage the van for a month, I can just plug in the
van for a month and it will safely maintain the batteries.
*) The manual for it specifically endorses using to support DC loads off the
battery. Many other chargers I looked at warned against using the charger
while DC loads were connected (not good for a camper), while some were
ambiguous.
*) It is compact enough to fit in the hidden electrical compartment with the
outlet/circuit breaker.
For the DC->AC conversion, I chose an AIMS 800 watt inverter:
http://www.invertersrus.com/pwrin800w.html
This inverter has a nice feature I didn't find in any other inverters
(except much bigger ones): the cooling fan is thermostatically controlled,
so the inverter is silent unless it is under a large load. It is also
reasonably compact. Another plus is that it is easy to disassemble (a
necessity since the fuses are inside.) This made it easier to wire up
external leds and an external switch.
To supply the outlets from the correct power source, I used a double-pole
double-throw switch as a transfer switch. I used this one:
http://www.mccampingsupplies.com/index.php?main_page=product_info&products_id=7845
It is rated for 20 amps, has standard screw terminals for the connections,
mounts in a standard electrical switch box, and even comes in brown!
This is an on-off-on switch. In my setup, up means inverter power, down
means shore power, center means nothing.
My original plan was to use a 3pdt switch, and use the third pole as a power
switch for the inverter. I only found "component" 3pdt switches, however,
and after beginning the installation using these, I decided it wasn't really
a good solution (it certainly wasn't "code", whatever that means in this
case).
Note: another possible choice would be an integrated converter-charger like
they have in big RV's. This probably would have its own automatic transfer
switch. I ended up not going this route because I wanted something that
would usually be silent, and because I wanted something that was small
enough to fit in the hidden compartments.
Wiring details: the truecharge is hardwired into the shore power line
upstream of the transfer switch. Downstream of the transfer switch is the
Pass and Seymour GFCI outlet, which also feeds (and protects) the hidden
outlet. (The stock 15a circuit breaker is upstream of everything on the
shore power line). (As I mentioned in an earlier email, the GFCI outlet has
an *very* slight buzzing when running off the inverter. I may try a
different brand of GFCI in the future, but listmembers and the Pass and
Seymour service people have convinced me the buzzing is harmless).
As mentioned before, the truecharge is located inside the hidden wiring
compartment. The inverter is located under the drivers seat. My subwoofer
amplifier used to be located in the hidden wiring compartment, and has now
been moved to the hidden space under the passenger seat. Since our van has
the stock swivel seats, this involved cutting some sheet metal with a
dremel.
The auxiliary battery is a Walmart group 41 battery with the receipt taped
to the top so I know where it is should I have to collect on the warranty.
The batteries are joined by 6 gauge wire and a stancor relay (located under
the passenger seat, since that simplifies wiring the amp off the aux
battery). The relay is fed off the firdge relay. Although I haven't done
it yet, I plan on using an Altronix 6062 timer relay off the fridge relay so
that the firdge can be set to run on DC for an hour after shutting the van
off, so that it can be run on DC during short stops without worrying about
accidentally draining the aux battery all the way. I ran 2 feet of 6 gauge
wire from the alternator to the starter (which is connected to the starting
battery by the stock 0 gauge wire) so that the alternator can deliver its
full charging current to the dc system.
Photos:
Here is the transfer switch and outlet:
http://people.cs.uchicago.edu/~wes/vanpics/closeup.jpg
The red button is wired as a remote power switch for the inverter, and the
leds are wired as remote power and fault leds for the inverter. Note that I
bothered to paint the outside of the switch and led housings brown! The
thing to the right is our propane detector. It controls a solenoid on the
propane tank. When the alarm goes off, it beeps, flashes, and shuts off the
propane. We haven't had any problems with nuisance trips. Notice the
on/off switch: this shuts off the alarm *and* the solenoid.
Here is a bigger view to see how it looks overall:
http://people.cs.uchicago.edu/~wes/vanpics/overview.jpg
The circuit breaker has been moved to the inside of the cabinet next to the
hidden wiring compartment. I forgot to take a picture of this, but it looks
just like it did before.
The only other evidence of the whole operation is from the cutting
underneath the passenger seat. You can see the list in the carpeting:
http://people.cs.uchicago.edu/~wes/vanpics/underseat.jpg
I should say: this project took me significantly longer than I anticipated.
Even more so than usual. I mean a really really long time!! The problem
was that I kept changing my mind about the best way to do things. I think
the way I settled on was pretty good, so if you're looking to do something
similar and need more information about what I did let me know.
-Wes