Date: Sat, 26 Aug 2000 14:37:13 -0400
Reply-To: Tom Moritz <tmoritz@bmi.net>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tom Moritz <tmoritz@bmi.net>
Subject: Auxillary battery installation follow-up (long)
Content-Type: text/plain; charset="us-ascii"
A little over a month ago I posted some e-mail describing an auxillary
battery system using Sure Power Industries' battery separator between the
chassis or starter battery and the auxillary battery. At that time I was
seeking anybody else's experience with this product. While I didn't get
any response detailing past experience I did get several e-mails asking me
to report back how my installation went.
Sure Power Indust. manufacutures two models, the 1314 and 1315, which work
with 12V negative ground charging systems of 100 amps or less. These
separators allow multiple batteries to be charged from one charging source.
When the batteries are not being charged the batteries are isolated. This
prevents discharging the chassis battery when drawing power from the
auxillary battery. The battery separator also prioritizes charging. This
is where these two models differ. The 1314 is for systems with a single
charging source. This describes most vehicles. When the battery connected
directly to the charging source reaches approximatley 13.2V the separator
will close its high amperage contact connecting the auxillary battery in
parallel. The 1315 is the same except charging sources can be connected to
either the chassis or axillary battery. When would you want the 1315? I
purchased it in anticipation of adding flexible solar cells and/or an
inverter/charger to our electrical system. These charging sources would be
connected to the auxillary battery. With the 1315, when the auxillary
battery reaches 13.2V, the contact would close and the extra power would be
used to top off the chassis battery. The 1315 was only $5 more. Both
models also have spade terminals for an auxillary battery status lamp and
manual override switch. The battery status lamp is illuminated when the
auxillary battery has sufficient voltage to assist the chassis battery for
starting the vehicle. The manual override allows you to force the
separator to close the contacts and connect the batteries. (This turned
out to be quite handy as I explain later.)
Installation:
The first step after acquiring all the parts was to remove the driver's and
passenger seat and captains chair swivels. I probably didn't need to
remove the passenger seat but it made lifting the chassis battery out
easier. The next step was to remove enough of the sheet metal from under
the driver's seat to allow me to install the Optima deep cycle battery. I
was able to do this with a 3/4" hole saw to drill the corners and a small
electric jig saw with a heavy duty metal blade. A test fit of the Optima
battery confirmed there was enough room to mount both the battery and the
battery separator in the auxillary battery box.
Next step was to drill holes in the bottom of each battery box. This is
the reason I had to remove the chassis battery. I lined the holes with
rubber gromets and ran a 5 foot length of 4Ga. battery cable from one
battery box to the other. I terminated both ends with a crimp on eye and
soldered it. I bolted the separator to the floor of the auxillary battery
box using self-tapping hex head screws. I then connected the chassis
battery (positive) to the battery separator primary terminal and the
auxillary battery (positive) to the battery separator secondary terminal.
(The primary and secondary terminal designation is not really important
with the 1315 model but very important with the 1314 model.) I also
installed a small normally open momentary pushbutton switch up on the front
of the seat pedestal where the driver can hold the button and turn the key
at the same time. This switch is connected to the start-signal and ground
terminals on the battery separator to manually close the contact. I also
installed a ground connection to the negative terminal of the auxillary
battery. Make sure you remove any paint from where you attach the
grounding lead to improve conductance. At this time I also replace the
chassis battery with a new one from the local NAPA auto parts store.
With that all done I was ready to test the installation. Turn the key
and....nothing! I checked my wiring and the voltage of the batteries. The
new chassis battery was at 11.2V. Hmmm...must have been on the shelf for a
while. Okay, let's test the manual override switch on the separator. Push
and hold, turn the key and the engine comes to life. I would have taken it
for a drive at this point but the seats were still out so I kept the engine
at about 2000rpm with my volt meter hooked to the chassis battery. When
the voltage was up to 13V I shut the engine down and installed the seats.
She started up right away and I went out for a test drive. Everything
seemed fine so I went home and parked her. Later that afternoon I went out
to start her and....nothing! I checked all my wiring to make sure I didn't
have an unintentional ground. Everything was good according to my meter.
I figured the battery was severly discharged when I purchased it so I
rented a charger and hooked it up for a slow charge. Three hours later
things looked fine so I returned the charger figuring the chassis battery
just needed a full charge. The next morning she started but with
difficulty and I drove to work. After work she wouldn't start without
connecting the auxillary battery with the manual override. Well, I drove
right to the NAPA store, pulled the "new" chassis battery, and told them
the battery was bad. Well, the skeptically put the battery on their test
stand. First test - failed. Test again - failed. This time I asked them
to test the replacement battery before I left the store. Something to keep
in mind five years from now when it's time to replace the battery again.
Fortunatly the bad battery wasn't too much of an inconvenience because I
was able to start the engine using the auxillary battery and manual
override on the battery separator.
I also hooked the fridge and water pump leads directly to the auxilary
battery instead of going through the relay which disconnected the DC when
the engine wasn't running. Now I can put the fridge on DC while we are
traveling and if we stop during the day I don't have to change over to
propane. I don't like to drive with the propane valve open in case of an
accident and I don't even know if our fridge will stay lit while driving.
We've used this setup for about three weeks of camping this summer. The
system works very well. Before the heat exchanger would defrost during the
day because I wouldn't take the time to change over to propane if we were
only stopping for an hour or less. Now that isn't a issue. The fridge is
doing a much better job keeping things consistantly cool.
Next phase is installing a low battery cutoff switch to protect the
auxillary battery. I have bought a product from Mobiletronix called
Voltminder. It is a solid state 15A/12VDC low voltage relay. This will go
between the auxillary battery and the camping equipment. The cutoff switch
will disconnect the battery from the camping equipment if the battery
voltage drops below 10.5V. It will turn on again once the voltage reaches
about 12.5V. While I don't expect to discharge our auxillary battery this
far intentionally I figured it was good protection in case the frige gets
left on DC for an extended period of time ie. after a long return trip home
and we are all very tired. I will let you know how this product works
after we've been using it for a while.
Parts list:
Battery separator - Sure Power Industries, Inc. 1314 or 1315. Web site:
http://www.surepower.com
Auxillary battery - Optima Battery D900M. Web site:
http://www.optimabatteries.com
Low voltage cutoff - Mobiletronix PC15A1VM. Web site:
http://www.mobiletronix.com - make sure you specify the a shutoff voltage
of 10.5 and reconnect voltage of 12.66V. They have a newer model with a
shutoff voltage of 11.5V. This is for applications where the battery has
to retain enough power to start the engine.
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* From the computer of: *
* Tom Moritz *
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