Date: Wed, 16 Jun 2010 15:19:50 -0700
Reply-To: "Mike \"Rocket J Squirrel\"" <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "Mike \"Rocket J Squirrel\"" <camping.elliott@GMAIL.COM>
Subject: Re: 12.2 V at rest ('85 Westy w/2.1L)
In-Reply-To: <023a01cb0d99$6e8f8d10$6701a8c0@PROSPERITY>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Scott Daniel - Turbovans wrote:
> Hi Rocket,
> not sure if I made it clear ...
> though I think I mentioned it twice...
> I had a fat volt less charging voltage at the battery than at the
> alternator with engine running and alt. charging.
Well, by golly, you're right. I did overlook that.
When the battery has been freshly discharged turning the starter, it's
going to be hungry for energy and will draw a lot of amps and there will
be fewer volts at the battery than are present at the alternator due to
resistive losses in the alternator > battery wire.
As one drives along, the battery will draw fewer and fewer amps as it
tops up, and pretty soon the voltage at the battery will be very close
to what's coming out the alternator. Other loads on the battery, like
headlights, will continue to cause fixed voltage losses.
In other words, if you got no serious loads hung off the battery, you
could pretty bring a battery to full enough charge through a 22 gauge
wire if you drive long enough.
But if one does not routinely drive very far, the battery may not have
enough time to become sufficiently charged so that its charging current
drops much. Under such conditions it would benefit the man or woman who
doesn't make long trips to provide a low resistance connection between
the alternator and battery, so as to jam as many coulombs into the
battery in as short a time as possible, especially if they do their
short trips in the dark with the headlights on.
As for that alternator to starter wire . . . well, that's going the long
way around, isn't it? Why bring the current from the battery to the
alternator then to the starter? Just bang in a chubby wire from the batt
to the starter and be done with the middleman.
My van would benefit from that. I'd like to find some hefty 2 gauge
primary wire for that but my Ace Hardware only has 10 gauge. Who's got
the good pricing on wire like that?
> about what is good charging voltage ..
> I think lower is better for longer battery life.
> Higher is better for good starting cranking.
It's all a balance. A little good beer makes me feel cheerful and
gregarious. Much more and I'm embarrassing Mrs Squirrel . . . and, the
next morning, myself.
--
Mike "Rocket J Squirrel" Elliott
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Westrailia: (Ladybug Trailer company, San Juan Capistrano, Calif.)
Bend, OR
KG6RCR
