Two recent threads have mentioned the sealed lead acid batteries as used in
UPS and golf carts, etc.  Things like this:
http://www.batterywholesale.com/battery-store/proddetail.html?prodID=2244
and other similar batteries.  BTW, if you open up one of the $59 jump start
units from Costco or the like that's what you will find inside, a 17 AH
sealed lead acid battery.
I have two such batteries that I acquired nearly ten years ago and use them
in the field for powering my telescopes, etc.  I charge them at home with a
special wall wart type charger designed for such batteries. A bank of four
of these (sell for around $33 no shipping if you hunt around on the
Internet) seems about the right size to fit the Vanagon aux battery
compartment.BUT, how will they hold up to a vehicle charging system?  Info
on some sites seems to indicate they will be okay, other info is ambiguous
And the main reason I asked is because of my experience several years ago.
I acquired two 65 AH sealed AGM batteries and used them when camping and to
run some of my astronomy equipment.  They were never hooked into the Vanagon
charging system, charged them at home, placed  under the rear seat, ran a
heavy cord out to run laptop, etc.  One of the batteries self destructed
very fast, I was charging it with a FLAPS auto battery charger but using the
setting on the charger for that kind of battery.  When it went away I went
to charging the second with the special charger mentioned above (much
slower) designed for the type of batteries shown in the link above.  The
battery lasted for another couple of years but also went south.
Because of that experience I've been hesitant to go with sealed or AGM
batteries that are not specified for vehicle use and therefore vehicle
charging systems.
Can anyone lend any info on the suitability of the Vanagon chargiong system
for maintaining such batteries in the vehicle?  BTW, I understand that these
batteries are not designated as 'Deep Cycle'.