Date:         Mon, 23 Jul 2007 20:27:11 -0400
Reply-To:     Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
Comments:     RFC822 error: <W> MESSAGE-ID field duplicated. Last occurrence
              was retained.
From:         Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject:      Re: Aux Battery Charging Alternatives Question for the
              ElectricalGurus
Comments: To: Susan Alfrey <svalfrey@comcast.net>
In-Reply-To:  <C2CA397D.601E%svalfrey@comcast.net>
Content-Type: text/plain; charset="us-ascii"

One thing that I discovered with my Smart Relay is that the starting
battery needs to be in good shape to deliver enough voltage to trip the
relay and charge the aux battery. Ran into this in the middle of Kansas
last July (106 degrees)... Fortunately I had a small generator with me and
got the van going again....  HVA/Tucson



I think there is some confusion here. Battery voltage alone should not
operate the relay. The relay is operated when one side is receiving a
charging level voltage. If the chassis battery is to low to start the van
normally, you have to ask why? What drained it and are the house loads or
accessories wired to it? Now if you ran it low and wish to use the house
battery to boost it. You need a trigger wire to operate it. You will also
need adequate wiring to-from the relay to handle that load. Now under
normal operation, when the engine starts, the alternator will supply
charging voltage to the chassis battery. As the charge voltage raises, the
relay will operate and connect the house battery so it will also be
charged. When the charge source is removed, the battery voltage will fall
and the relay will disconnect separating the two batteries. That is how it
is supposed to work.



Dennis





-----Original Message-----
From: Susan Alfrey [mailto:svalfrey@comcast.net]
Sent: Monday, July 23, 2007 1:55 PM
To: Dennis Haynes
Subject: Re: Aux Battery Charging Alternatives Question for the
ElectricalGurus



on 7/19/07 5:22 AM, Dennis Haynes at d23haynes57@HOTMAIL.COM wrote:

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/


One thing that I discovered with my Smart Relay is that the starting
battery needs to be in good shape to deliver enough voltage to trip the
relay and charge the aux battery. Ran into this in the middle of Kansas
last July (106 degrees)... Fortunately I had a small generator with me and
got the van going again....  HVA/Tucson