Tuesday, September 10, 2013

Car starting in Winter

Was talking to youngest son, who is out in Minot, North Dakota, about getting his car ready for winter.  Winter in Minot is really really bad.  I recommended he put in a block heater rather than a freeze plug heater, and carry a really long extension cord.  Northern NH winters are harsh, but not so harsh as to require block heaters, where as in Duluth, Minnesota, in which I spent three winters, every car in the city had a block heater. You could tell by the plugs hanging out of the grilles.
   Conversation moved on to other things, but later, I thought of  a number of winter car tricks that I hadn't passed on.  Hence this post.
    Cars have improved greatly since I started driving.  We have alternators now, which throw a lot more juice than the old DC generators,  keeping the battery charged.  We have fuel injection, controlled by clever microprocessors which are much better at getting the mixture right than feet made clumsy by ski boots.  We have solid state ignition that throws a spark so hot it will fire plugs burned out to twice the proper gap.  At 20 below, a 2013 car will most likely crank up and go, whereas a 1957 Chevy most likely would not. 
   One thing that has not improved is the battery.  Being chemical contraptions, they slow down as they get cold.  Batteries are rated for total capacity, (usually 80 ampere-hours) and cold weather cranking current at zero degrees.  (usually 800 amperes)  As the temperature drops below zero,  cranking current goes down. By the time forty below is reached, the battery may not have enough current to light the dome lamp.
   When the weatherman is predicting really cold, you can just bring the battery indoors to keep it warm.  In the morning, a nice toasty warm room temperature battery will crank with enthusiasm.  Or stick a 100 watt light bulb under the hood next to the battery.  Mechanic's trouble light works well.  Stock up on 100 watt bulbs, the greenies are banning their sale.  Or stick a battery charger on it.  The charging current warms the entire battery, as well as bringing the charge up.
   Batteries last three, maybe four winters.  Then they go weak, and won't crank in cold weather.  How to tell when the battery is getting old and tired.  Check the voltage with a multimeter.  A good battery, fully charged, and warm, say after a two-three hour drive, will show 12.8 volts.  As they age, they show less.  When the batttery gets down into the eleven volt range, it's time to go to Sears and get a  Diehard.  Battery voltage is measured engine off.  When the engine is running, what you see is alternator voltage, which needs to be 14 volts or a little more to charge the battery.  If alternator voltage is low, that's the reason your battery voltage is low, the alternator isn't doing it's thing and charging the battery.
When the car fails to crank over,  get out and touch each battery terminal with your bare hand.  If you feel one of 'em getting warm, that's a sign it isn't making good contact.  Couple of times over the years, I have gotten the car to go by pulling the cable off, polishing the cable end and the battery terminal and putting it back together.  You do carry tools in your car?  All you need for this trick is pliers and a pocket knife.
   The sun is your friend in cold weather.  Mid day sun can warm a car up to nearly room temperature, which makes starting more certain.  It may not help if you gotta get to work, but if all you have to do is go to the store, do it at mid day.  Brush the snow off the car so the sun can get at it.
    Back the car into the driveway.  Should you need to jump start it, it's much easier if the hood faces out to the street.  You do carry jumper cables?  It's also easier to ram out thru that snow drift the plow throws across your driveway going forward, rather than backing into it.  Leave the parking brake OFF.  It can freeze ON, and then you are stuck til it melts out.  

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