It is a old topic here but time for it again I guess. Lots of us need
new batteries from time to time or wish to add a second battery. What
fits? That is the question all right. I recently needed several
replacements and have switched to a slightly different size.

Group 41 seems to be the native battery for Vanagons. There are others
that fit into the compartment too.

Group 41   standard size, sort off
Group 42   smaller, weaker option
Group 48   very close to standard but easier fit into compartment?
Group 91   standard size, maybe stronger?
Group 40R  maybe close but don't have details

I am now using some Group 48 as a trial as I wanted a size slightly
easier to fit in/out of the compartment. It is same height and width but
slightly less long. It also has a bit better CCA and CA numbers than the
41 at the same megastore chain.

An anomaly I have noticed is that the supposed "standard" size
dimensions can vary slightly from brand to brand and the size charts can
be way off from reality. Group 48 for example is often listed with
physical dimensions larger than the Group 41 but the ones I just bought
are smaller. Is it an error in the charts? An error by the manufacturer
in labeling? Anyone else using this size under the front seats with
unmodified battery compartment?

Mark