Please Explain Battery Isolator Operation/Function

[Eric Johnson]

My coach has 4 - 6 volt AGM batteries that serve as starting and accessory DC
supply. I have
a gel battery mounted in the generator compartment that starts the generator. I
have an
"isolator" in the coach battery compartment with leads coming from the coach and
generator
batteries. I use a Xantrex 40 Truecharge, located in the center driver's side
compartment, to
keep the coach batteries charged. On the dash I have a rocker switch that reads
"auxiliary
battery". My understanding of the dash switch is you can use it momentarily to
augment the
coach batteries if they're too low to get the engine started.

I've read a number of references to isolators but am clueless on how they
function and would
appreciate some education on the subject. I'm particularly curious if my Xantrex
charger may
be supplying the generator battery as well as the coach batteries. Xantrex says
mixing battery
types with the same charger is not a good thing.

Eric Johnson
84FC35SB
San Antonio Texas