Date:         16 May 1997 15:01:31 -0600
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         "Carl Hansen" <Carl_Hansen@ATK.COM>
Subject:      deep cycle battery fitment

 BatSubject:     deep cycle battery fitment             5/16/97    2:59 PM
In answere to will deep cycle battery fit.

OK, I've looked at this subject myself because I'm setting my non-camper '89
Syncro up for camping duty.  It doesn't take a rocket scientist to figure out
that the VW batteries, Group #41 and 42 if memory serves, is different than
other battery groups.  In short, they are SHORTER.

So look at what you have under your seat.  It will be a group 41 or 42.  Close
the lid, and you will see that you can't hardly put a pencil in between the
lid and the battery, that's why VW has the plastic covers over the positive
terminal.  That's why the battery under you driver's seat is probably NOT a
deep cycle battery at all, rather it's another group 41 or 42 standard
battery, least ways it is in my brother-in-laws 86 camper.

Now it also doesn't take a rocket scientist to look at a group 41 or 42 next
to a 24 or 27 or other group to see that most other batteries are
significantly TALLER than the pencil you can't hardly fit between the battery
top and the lid.  That's why there is a group 42 and 41 designation for the VW
battery, they fit in shorter spots.

So are you hosed?  Well, yes and no.  There are deep cycle batteries that are
short enought to fit under the seat.  The problem is, IMHO, they don't have
the capacity to do squat.  i.e., they will run down too fast to be of much
good for anything.  You might be able to run a couple of lights for a little
bit at night, but don't expect to run your electric cooler all day long.

Anything the size of a group 24 or 27 just isn't going to fit under the front
seat.  So, why don't you hook it up under the back seat.   I'm going to hook
up the biggest deep cycle battery I can get in a plastic case and install it
under the back seat.  I haven't figured out the details yet, but I figure the
starter terminals are just the other side of the sheetmetal, so it's the most
logical spot to put it.  People over at Batteries Plus here in Minneapolis
tell me that most vehicles should be vented enough that I shouldn't have to
worry about battery fumes. 

I was surfing misc. vanagon pages the other day and came across an interesting
article that bears on the problem at hand.  The URL is listed below.  It
discusses the pro's and con's of passive isolators vs. relays vs. active
isolators.  I haven't read it in detail, but in skimming it I felt it was a
good disertation on the problem.

http://halfdan.med.umn.edu:8853/misc/archives/Files/Motorhome--Alternator-Charging-Systems

The tech tips site that listed the artical is also of interest so I'll list
that here also.

http://killer-whale.automatrix.com:80/~skip/volkswagen/tech-tips.html

Does that answere your Question??

Ch   '89 Syncro GL