Im interested in hearing what it is also.  I thought the Trojan J-150
AGM  Deep Cell Battery having 150 amp-hours was pretty good, but, im
sure theres better . Hopefully someone in here will tell us along with
the specs.

I see where <nospam@sbcglobal.invalid.net> contributed:

A pair of 6v golf car batteries in series.  Around $50 each at Sam's
Club.

Will Sill
The Curmudgeon of Sill Hill

Another one of these impossible to answer "what's the best" questions.
Like with most of these questions the party asking gives little detail
to help define BEST.

Is "longest lasting" a reliability, battery capacity or depth of
discharge kind of question?

Are you asking brand or battery type?

Are you aware there a few companies that make automotive type lead acid
batteries?  These few companies make batteries for many companies that
are marketing batteries under there own brand.  Are you aware that for
even major brands like say from Sears and their Die-Hard brand, they may
be manufactured be different companies in different parts of the
country.  There might be small differences depending upon which factory
they came from.  Marketing companies change suppliers from time to time
and so would any comments be valid for a specific brand.  Example,
everyone knows Wal-Mart/Sams and was recommended in one of the posts.
In this area Wal Mart's batteries were manufactured by Johnson Control,
one of the largest LA battery mfgrs in the country.  Last fall they
dropped Johnson Control and are now being made by Exide.  So is any
comment about this brand still valid.  Are the Exide made batteries you
buy from WM any different the the batteries bought from a different
chain with their own brand on them that are built by Exide also?

Battery type, there is the convientional wet cell, the gel cell, and the
starved electrolyte (AGM) construction.  Each have there own
characteristics.  Within these groups you have batteries intended for
starting engines, there are others intended for deep discharge and there
are variations in between.

Then you have the situation of regional availability.  Do you want a
brand that is decent but would be difficult to find warranty coverage if
you are away from an area where this brand is offered?  Would you care
if that replacement battery with same brand and model number were made
by a different battery mfgr and possible perform differently?

Does battery location present a problem for normal and regular
maintenance?  If so maybe one of the maintenance free typs may better
suit your needs even though it may not be the best choice from other
characteristics stand point.

Sorry to be giving what some would consider a smart-a.s response but I
hope it does show the futility of a "what's best" kind of question.

Mickey

I'm an expert on deep cycle batteries as I use them in my all-electric
RV. The best batteries, by far, that I've found are made by Rolls. They
have a SEVEN year warranty and high storage capacity.

Check them out here:  http://www.dcbattery.com/rollssurrettemarine.html

Harry Harris

Rolls/Surette