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Re: Heated Batteries

Excerpts from audi: 25-Jan-95 Re: Heated Batteries by Alan Cordeiro@adi.com 
> I have heard of a recommendation to turn headlights on for a few
> minutes on really cold mornings ( evenings, nights ) and then turn
> them off for a few more before trying to start your car. The
> theory behind is that the 20 amps or so flowing through the 
> battery will warm it up a bit, perhaps five or ten degrees. The
> short gap allows the battery to recover, and the heat to
> evenly spread all over it.
This seems to make good sense.  On my 81 5000 Diesel, I have to
regularly crank 15 to 20 seconds(or more) when the temperature drops
below about 20F, when it drops below 0F, I have to crank at least twice
that long.  With my larger than average diesel battery, I notice that my
car actually turns over faster and faster as time goes by.  

IMHO, you would never need to heat the battery anyway.  With a good
battery, good charging system, fuel without water in it, synthetic oil,
and the benefits of electronic ignition and fuel injection, no properly
maintained(gas engined) car should have trouble starting.  If it's
really cold(30 or 40 below), you shouldn't be starting your car anyway
unless you have a block heater.  If you don't believe me, time how long
it takes to empty a quart bottle of engine oil when it is below 0F.  If
it's so cold that your engine isn't lubricated properly when it starts,
you should leave it at home and snowshoe to work.  

Many people with perfectly good batteries neglect them terribly. 
Batteries should not be left in subzero weather unless they are fully
charged.  Many people wonder why their car won't start when they have
new batteries.  Frequently, people drive home from work with their
headlights, foglights, heater fan, rear defroster, radio, CD Changer,
Alarm System, Cellular phone, CB Radio, Windshield Wipers, Heated seats,
Heated Mirrors, Radar Detectors, etc on, which create a load that their
alternator cannot keep up with; so they leave their battery
half-charged.  Then they leave all of this stuff on as they start the
car the next morning(luckily most Audi's have load reduction relays
which turn this stuff off while the starter is engaged).  It's always
fun to jump start someone who says"I started my car, went inside to wait
for it to warm up, but when I came back out it was stalled and it
wouldn't start again.  Most alternators won't keep up with the load of
extra gizmos when the car is only idling.(5000 diesel have an idle speed
knob on the dashboard)

If you want the ultimate advice in cold weather starting, look to
truckers and loggers.(People who have to start Diesels in cold weather
know lots of tricks)  Sometimes they use the brute force method i.e. big
batteries, jumper cables, and a big can of ether, but there are much
more clever tricks.  A logger I know in Vermont put hydraulic quick
connect fittings on the heater hoses of his Chevy truck.  Every morning
he would drive into the woods, and connect the cooling system of his
truck into his skidder.  After 15-20 minutes of circulation, his skidder
would fire up like it was July.  Some truckers have propane fired block
heaters.  But the best advice is, if you don't want to have to start
your car in the winter...leave it running all night like truckers do. :)