Date:         Wed, 16 Jun 2010 17:31:51 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: 12.2 V at rest ('85 Westy w/2.1L)
Comments: To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
In-Reply-To:  <023a01cb0d99$6e8f8d10$6701a8c0@PROSPERITY>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 05:18 PM 6/16/2010, Scott Daniel - Turbovans wrote:
>the guy who originally turned me onto solid state adjustable voltage
>regulators for Bosch alternators ...and starter/alternator rebuilder guy -
>he likes to see them run at 14.5 volts.

Dear Scott,

This is band-aid stuff.  The place that the voltage matters is
directly at the battery posts, and having the regulator measure it
there means that it doesn't matter whether you have thick wire or
thin, good tight connections or lossy ones, high current drain or low
-- the alternator is going to put the designated charging voltage
into the battery.  In that case 14.5 volts is definitely too
high.  Automobile batteries are operated in what's called "float"
service, where they are never more than slightly discharged except in
emergency.  13.8 volts at room temperature is probably a pretty good
voltage for floating a car battery.

People who actually discharge their batteries, i.e. camping service
with more than minimal battery use, are looking at a whole 'nother
kettle of fish, both with regard to charging and to the battery
itself.  For those people no single voltage is satisfactory -- the
float voltage won't charge the battery fully, and the charging
voltage must be removed once full charge is achieved.

Yours,
David