Hi Frank, I'm not seeing any normal conditions where my relay system is
at a disadvantage when compared to the 1315. My starter battery is
always connected to the charging source, just like in a system using the
1315. My aux batter is connected to the starter battery/charging source
under only two conditions:

1. The alternator is putting out enough voltage to extinguish the dash
ALT lamp. What's that -- 13 volts or more? Bridging the aux battery to
the starter battery under these conditions is appropriate unless the aux
battery has suffered a major failure, in which case all bets are off
with my system.

2. I have operated a switch to manually bridge the aux battery to the
starter battery/charging source by applying voltage from the aux battery
to the relay coil. This would be done in the case where the starter
battery is low and I need to steal some power from the aux battery to
pump up the starter battery. There also should be no problem unless the
starter battery has suffered a major failure.

I did use the phrase "normal conditions" in my opening paragraph, and I
noted above two unusual conditions which involve the near or total
meltdown of one or both batteries. In the situation where the aux
battery was hosed, the 1315 would allow a fellow to keep driving because
it would refuse to connect the bad battery, whereas my system has no
such safeguard. If the starter battery is low, both systems allow a
fellow to bridge the aux to it for starting, but if the starter battery
was massively failed neither system would help.

The 1315 does not require metering: it appears to be smart enough to not
connect ugly-dead batteries to the system. So that's an advantage -- but
to me, not much of one because I like meters -- even with a 1315 I'd
monitor battery voltage.

So, unless I'm missing something, the 1315 only provides two advantages
over the relay system: no-brainer operation (always useful when you have
a squirrel's brain) and it refuses to connect a hosed aux battery. Those
two may be advantages enough for some folk to recommend the 1315 to
them, but to say that "relay systems work but not well," is a bit much.

--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR

Frank Condelli typed:
> In a message dated 20/02/2007 3:11:46 P.M. Eastern Standard Time,
> LISTSERV@GERRY.VANAGON.COM writes:
>
> 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.
>
>
>
>
>
> OOPS  ! Big screw up here !  Now's it's me giving out false information.  My
> good friend Mike brought this to my attention.  After re-reading the
> document that comes with the Sure power 1315 I see that the two batteries are  indeed
> connected together under two circumstances.  One, when the aux start  feature
> is connected and the main battery is found to be below the level of the  aux
> battery at starting then the aux battery is connected to the main battery to
> aid in starting the vehicle.  Two, when both batteries reach a charge of 13  ~
> 13.5 volts, both battery banks are connected together.  Sorry for
> propagating false information.
>
> Cheers,
>
> Frank  Condelli
> Almonte, Ontario, Canada
> '87 Westy, '90 Carat, '87 Wolfsburg  (Forsale) & Lionel Trains (_Collection
> for  sale_ (http://members.aol.com/Fkc43/trainsal.htm) )
> Vanagon/Vanagon Westfalia Service in the Ottawa Valley
> _Frank Condelli &  Associates_ (http://members.aol.com/Fkc43/busindex.html)
> _Vanagon  Stainless Steel Exhaust Systems_
> (http://members.aol.com/Fkc43/stebro.htm)
> _BusFusion_ (http://members.aol.com/BusFusion/bfhome.htm)  a VW Camper
> camping event, Almonte, ON, June 07 ~ 10,  2007
>