Being in the mood to install a 2nd battery in my 82 Westy, I have been
reading the archives about the SurePower isolator and the more recently
mentioned combiner. The drawback to the isolator I had assumed to be about a
.7 volt loss in charging and some modification to the alternator regulator.
The battery combiner seemed to be the ticket as it didn't have these problems
and in addition could (optionally) be used to combine the 2 batteries for
emergency starting. The SurePower people tell me, however, that for Vanagons
the best choice is the isolator and that the supposed .7 volt charging loss
is actually compensated by increasing the charging rate the same amount. Also
the isolator being solid-state would last longer and be more trouble free
than the electo-mechanical combiner besides being half the cost.
Looking at the West Marine catalog the isolator again is mentioned as losing
that .7 volt and not being the best way to go.
I am probably going to use a deep cycle lead acid battery until I can afford
the spiral-wound or gel cells. What am I missing here? Is the isolator OK?

Ken Hunter
82 Westy 1.9D
84 Jetta 1.5D
89 Mitsubishi van