On Wed, Aug 10, 2011 at 10:35 AM, Dennis Haynes <d23haynes57@hotmail.com>wrote:

> Anyway there are two considerations for venting reqiurements. One is for a
> vehicle and the other is for a dwelling or living space. Passenger Vanagons
> do not seal the battery compartment. Flip top cover and a vent-drain on the
> bottom. Campers as a dwelling get the sealed, screwed down battery cover.
> This is particualry important if you paln to add charging capbility while
> the vehicle is occupied such as when sleeping.
>

I think Dennis has answered a basic part of my original question on the
importance (or not) of venting.  Never having owned a non Westy I was not
aware that the battery compartment is only sealed in the campers.  That
implies, at least to me, that VW (and the various bureaucrats that have
power over such things) did not consider the open battery a hazard in normal
use but added what might be called an abundance of caution for the camper
where people would be living in the van.
An additional thought on this subject.  I've been following several Vanagon
and Vanagon/Westy related Internet list for about 10 years now.  And I don't
recall a single instance where someone reported any kind of problems related
to venting or no venting.  I have to come to the conclusion that given
normal use and prudent behavior there is not a problem.
But I'll close with this admonition,  posted many places including owners
manuals and stickers in most vehicles:  Don't cause a spark at the battery
like when jumping from or to another battery!  Ground to the frame (so no
spark occurs right at the battery) and always connect the ground LAST!