Tom you are right isolators are diodes that allow current to flow inone direction
so if you hook the charging circuit to two batteries it "isolates"the batteries
from trying to charge each other. so you can use energy from battery#2 and the
primary battery is still 100% to start your vehicle. you could putanother single
diode in the charge line of the trailer and charge the trailer battery.but its a
one way street so you can't borrow from it to start the tow vechicleand the
trailer can't use the starting battery. In boats it can be a more serious
situation as you need that cranking battery to get back home so youhave to be
real careful that the cranking battery is ready to start the big engine.With a
relay between the two batteries if you have control you can borrowenergy "if need
be" to Start the tow vehicle. I think you have to have a good understandingof the
situation and how your system works or your better off calling AAAor Good Sam. It
would be nice to add a couple of diagrams here with circles and arrowsetc. but
alas I don't have the technology.. Dave from Pepperell

"Tom H." wrote:

> Courtney,
>
> After thinking about how the isolator is set up (it is actually abig diode),
> you are absolutely correct that I will be potentially draining boththe vans
> main and deep cycle batteries so in retrospect this would not bea good idea.
>
> I guess that I can connect to the auxiliary (deep cycle) batteryterminal but
> am still concerned about the mismatch with the trailer batteries.I suppose
> ann ideal situation would be to use a three battery isolator butI am not
> excited about spending another hundred and some dollars on a largeenough
> 3-battery isolator (I presently have a 165 A isolator), particularlysince the
> present isolator is working well after having problems with smallerversions.
>
> Tom H.
>
> Courtney Gwyn wrote:
>
> > Thanks for your reply, I too run dual Optimas in my Sub, with aWrangler 170
> > amp alternator and solenoid isolator. It's my understanding thatif you
> > connect to the alternator you are effectively connecting to yourmain
> > battery, as they are hardwired together and not separated by theisolator.
> > Convention dictates the charge wire should be hooked to the auxiliary
> > battery, Perhaps Mr. Dunmyer could jump in here and help with anisolating
> > relay. I'll try West Marine for those panels, thanks-Courtney