Re: Dead Battery

[Robert Houk - SMCC Bos Desktop Hardware <rdh@UrQ.East.Sun.COM>]

   In the fall of last year I picked up a new heavy duty battery after the last
   one expired after five or so years. Because I had the car in semi-storage
   through the winter I usually started it every two weeks or so to 'excercise'
   the air conditioner. I would simply run the car for a few minutes and then
   shut it off. I last started the car about a month ago and now find that the
   battery is almost dead. There's still a little juice left but not enough to
   turn it over. The question is, is it the battery or is there a bad ground
   somewhere. What and where should I check? 

First, you want to run the engine more than "a few" minutes, I'd say
at least 15-20 minutes, just to recharge the battery. Batteries "leak
down" on their own, even "not connected" to anything. If the battery
is accessible, use a hydrometer to check the specific gravity of the
acid in the battery; most auto parts stores have them for a few bucks
and "calibrated" (which is to say "marked") for lead-acid battery use.
It takes a minute or two just to recharge from starting the engine
(assuming that it started "right up"; if you have to crank it awile to
wake it up, *MUCH* longer)!

All of this is of course not to say you don't have some other problem,
like enough corrosion/whatever somewhere to form a small leakage current
to ground. A small radar detector can completely drain your battery in
just a week or two. You might also make sure you've got nice clean
battery post/cable connections that are firmly clamped. (Disconnect and
clean to "shiny" metal then reconnect and firmly clamp down.)

Second, you want to run the engine long enough to thoroughly warm it up,
specifically to heat up the oil to the point that it boils out all the
water that has condensed inside the engine (exhaust, etc.) from having
started it in the first place. This [typically] takes a *LOT* longer
than "warming the engine" as indicated by the coolant temp (e.g., cycling
the radiator fan). If you don't boil out all the water, you build up di-
lute acid bath in your engine/oil . . .

					-RDH