Date: Mon, 5 Apr 1999 14:45:00 -0700
Reply-To: Davidson <wdavidson@THEGRID.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Davidson <wdavidson@THEGRID.NET>
Subject: Re: 2nd battery...an alternative??
Content-Type: text/plain; charset="iso-8859-1"
Jim,
The battery that you mention sounds very interesting. It certainly has its
advantages, like flexibility, portability, and ease of installation. Also,
doesn't cost any more than the Optima battery, and you save the cost of the
other components and labor involved with a more permanent installation in
the box under the driver's seat. On the other hand the Optima installed
under the driver's seat has its advantages too.... Like it is out of the way
and doesn't take up so much space.. and does its job pretty much
automatically for years and years.
The Optima is about 40 lbs. for about a 60 amp hour rating (about 50 useable
down o 10.5 amps). So with all the extra gismos I would think the battery
you are proposing would weigh more if it is rated at the same number of amp
hours. One thing to think about: is your proposed battery a deep cycle
battery? Deep cycles are designed to be drawn down frequently; starter
batteries are not. If it is not a deep cycle, it may last only a fraction of
the life of an Optima deep cycle.
Sorry if my article made the installation seem complex or intimidating.
Really, only the research was complex... mostly due to my anal retentive
compulsion. But once the research is done the installation is pretty
straight forward. If you wanted to do the installation, I'm sure you could
get lots of advice and support for several of us on the list.
The key to figuring how long a battery will run your appliances is to know
two things. You need to know the 'amp hour' rating of the battery; not just
the maximum amp output. You also need to know how many amps the appliance(s)
will use when turned on. The calculation is pretty simple: example, my
Optima battery will supply about 50 amps hours as the battery draws down
from 13 volts to 10.5 volts. (Below 10.5 volts many appliances like lap tops
will not operate correctly.) My lap top uses about 4.5 amps (depending on
how much of the time the disk drives operate). So divide 50 by 4.5 and you
get about 11 hours that I can run my laptop. There are many variables
including temperature, but this gives you the idea.
One other thing... if this battery you propose has the same amp hour
capacity as the Optima and you deeply discharge it... you could be looking
at... 40 amps or more going through the wires that connect your battery to
the cigarette lighter when you go to recharge it. That would most likely
blow the fuse on the main panel for that circuit. That situation could put
you back to my article which was mostly about how to size the wires and
other components for charging the auxiliary batter.
Good Luck,
Bill
90 Westy Syncro
-----Original Message-----
From: Jim Fritz <jfritz@DECORAH.K12.IA.US>
To: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM>
Date: Monday, April 05, 1999 11:50 AM
Subject: 2nd battery...an alternative??
Volks,
I've listened to all of the various ways many of you have devised to make a
2nd battery work in your Westys. You folks are very ingenious! However,
after reading the excellent post by Bill Davidson about what he did to hook
up his battery in his Synchro, I knew I was in WAY over my head. So, being
basically lazy, I went looking for an easier solution that might answer all
of these same issues with out the headaches. I'd like your comments, roses
or thorns, regarding what I am considering doing.
Basically I've found one of these sealed 600 amp lead batteries that come
with jumper cables attached, a 12v DC power port, 110-v power outlet,
worklight, AC charging cord, DC power inverter/charging cord, built-in cord
storage, and battery level indicator. Its supposed to hold an 8-12 hour
charge orver 6 months. The ad says it will power a standard house lamp for
8 hours so who knows how long you could run a cell phone or laptop?! You
can store it on its side or upside down because its sealed and charge it
from your cigarette lighter as you go down the road. It costs $160 so its
not cheap but it eliminates the electrical engineering degree (which cost my
brother big $$ and 4 years at Iowa State) and I can transfer it to other
vehicles and other outdoor adventures. It looks like its about 16" X 16" X
4" and a similar one that I saw weighed about 20-30 lbs. What's your
thoughts on this easy way out?
Jim in Iowa
91 Passat Wagon GL
89 Westy
66 Beetle
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