Good morning, Frank.

You say that with a SurePower 1315 that the batteries are never
connected together ... but that would be for normal operation.  However,
the 1315 can be wired so that the aux battery can assist the starting
battery if necessary (and the aux has enough oomph).

The way I read the 1315 operation is that it's actually a "Smart Relay"
and won't bring the aux online for charging unless the starting battery
is up to about 13.2 volts.  It would then drop off the aux if starting
battery voltage dropped to about 12.8 volts.

Anyway, the 1315 is what I intend to put in mine this spring.

Mike
Houlton, Maine

Frank Condelli wrote:

> Using  the Sure Power 1315 Battery Separator solves all your problems.  The
> batteries are NEVER, NEVER, EVER, connected to one another.  That's the  whole
> point of using the Sure Power device !  We've been over this a  gazillion
> times if not more !  Relay systems work but not well,   isolator systems work a
> little better but still not correct.
>
> Cheers,
>
> Frank  Condelli