The sure power isolator or smart relay is actually a voltage controlled
relay. It connects the two battery banks when either one is being charged.
When the charge source stops and the voltage returns to a battery only
state, the banks are again isolated.

Dennis

>From: Kenneth Lewis <kdlewis@NORTHSTATE.NET>
>Reply-To: Kenneth Lewis <kdlewis@NORTHSTATE.NET>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Re: Aux Battery Charging Alternatives Question for the Electrical
>             Gurus
>Date: Wed, 18 Jul 2007 18:57:57 -0400
>
>Loren,
>    Personally, I would add a relay that connects the aux battery (to the
>alternator)only  when the car is running. Otherwise you run the danger of
>discharging both batteries.
>    I would not use steering diodes due to the loss of precious electrons.
>    When in camping mode, I am too lazy/forgetful to use a marine battery
>selector.
>Ken Lewis
>http://neksiwel.20m.com/