I have only seen nipples on some batteries. I cant' advise whether
they are worth or not (for myself I don't worry). My owner's manual
makes no mention of a vent tube in the removal of battery instructions.

The place where the battery is mounted is not sealed gas tight, with
or without a gasket in the access lid. So i really doubt, even if the
rest of battery spot was sealed, that the lid can form any kind of
gas seal at all.

Why did they put a gasket on the lid when the rest of battery
compartment is so open to the van (underseat) ? Noise control is as
good a guess as any.

As Don pointed out, battery explosions happen when the gas builds up
inside battery due, in his case, over charging, and the integral
battery vent, if present, fails shut. Maybe the gasket is there to
contain some of the resulting splash? :)

I really wouldn't worry about H2 off gassing during normal operation.
I do believe in taking care of the battery, checking voltage and
periodically taking it out of van for an inspection, clean up, and
bench charge. Mind you, I bet more accidents occur during removing
and installing batteries than at any other time.

alistair

On 1-Oct-10, at 1:59 PM, Dave Mcneely wrote:

Alistair, I don't think we are arguing.  I asked you, as a short cut
rather than looking up the chemistry I once knew.  So, you think
little or no hydrogen would be present, and any that was would be
effectively vented if the original vent setup was in place.  None
produced during the jump start process.

And I did think the lid gasket was a part of the vent system to
prevent gas from venting into the interior of the van.  Fact is,
another list member once told me that, one whom I trust to be
knowledgeable about most things to do with the vehicle.  But you
think the gasket is mainly for noise control or something of that
nature?  Not to confine whatever is in the box so it doesn't enter
the van?

I have a non-spec battery, and I see no nipple anywhere on it.
Should I get rid of it and put in a spec battery, and a vent hose
(none evident in the battery compartment).

thanks