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RE: Cold Start Myths

To: "'Steve Laifman'" <Laifman@Flash.Net>,
Subject: RE: Cold Start Myths
From: Chris Thompson <cthompson@rrinc.com>
Date: Mon, 17 Jan 2000 15:26:57 -0500
Robert Palmer must be off today.  I fully expect we'll get a dissertation on 
this, but I recall doing the calculations in Physics 101 twenty some years ago 
showing that the heat generated by turning on the lights prior to starting (and 
then turning them off when starting) had net positive effect.

Since this was Physics 101, I'm sure there were numerous simplifying 
assumptions.  But the Professor swore that it worked.....

Chris Thompson
Executive Vice President
Recognition Research, Inc.
1750 Kraft Dr. Suite 2000
Blacksburg, VA 24060
540.961.6500
540.961.3568/fax
cthompson@rrinc.com
www.rrinc.com
B382000331

-----Original Message-----
From:   Steve Laifman [SMTP:Laifman@Flash.Net]
Sent:   Monday, January 17, 2000 7:16 AM
To:     BRENNAN,STUART (A-Andover,ex1)
Cc:     Tigers (E-mail)
Subject:        Re: Cold Start Myths

Stu,

With all due regard to the knowledgeability of Theo Smit and Steve Murphy, for
whom I have the utmost respect.  And, since I'm freezing here at 75 F today, let
me share some of my experience.

I did live in Illinois for 6 miserable years.  Just across the Lake/Cook county
line on the Lake, where 2 weeks of below 0 weather (F, not C), and 
mosquito/muggy
summers left me 1 month of nice weather, I scurried back to California, where I
was born.  Now don't get me wrong, Illinois, other than the weather, was a
marvelous place to live.  The people were just great, the schools good, the
Italian food fantastic (bought forget Mexican food).

So, back to the cold - really cold.  Luckily my car was in a semi-heated garage.
But, I've had to park at the airport with below 0 for days.  Getting started was
no joke in the middle of a parking lot.  They did have a truck that came by with
jumpers, though.

Many people owned a 'battery heater' from Warshawsky's (J.C. Whitney, to the 
white
bread people), as well as a 'block , or sump heater', which could plug in if you
were at home.  So the battery, and engine were relatively warm.

The concept that cold electrolyte decreases power is accurate.  So the question
is, "does a 20 amp drain heat the battery electrolyte sufficiently to make up 
for
the power it has drawn".  Of course, you wouldn't start the car with the lights
on, but 20 amps times 12 volts is 240 watts into the lights.  I've got to 
believe
that figuring the resistance of the battery into that equation would show a heat
dissipation in the battery.  The only issue would be 'is it sufficient to 
overcome
the drain and make a difference?'.

I'll leave the calculations to the electronickers and thermo-dynamicists, but 
it's
in the correct direction, and not totally ridiculous, like those Passive Radar
Jammers.

Steve

--
Steve Laifman         < Find out what is most     >
B9472289              < important in your life    >
                      < and don't let it get away!>

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