[Shotimes] Battery/Alternator testing questions!

[Ron Childs]

Two things will make your battery voltage decrease while the car is off.

1. A bad battery that will not hold the charge.
2. A current drain.

You can check for #2 by using an ammeter (a function on a VOM) in series
with a battery cable. You should unplug the light bulb under the hood so
its draw does not register. The current draw with everything off should be
very minimal, only the clock, radio memory etc. Probably a few (dunno how
many but well under 100) milliamps.

To find an unknown current draw, you need to pull and replace (not with
new ones) fuses, one at a time, until you identify the circuit with the
current draw. The owner's manual should list the various accessories
connected to each fuse that might be the source.

To check for #1, bring the battery in to your local auto parts store to
have it load tested.

-Ron Childs  '91


--- Steve Tatro <stevetatro_shotimes@att.net> wrote:
> Help.
> 
> This has happened for a couple of days now.  My car is sluggish to start
> when
> it's been sitting for a long period of time, seems like the classic weak
> battery syndrome.
> 
> When I got home I got the voltmeter out and it registered 13.96VDC when
> running.  It's been off for about an hour and now the battery indicates
> (with
> the car OFF) 12.75VDC.
> 
> My question is, how do I determine if I've got a bad alt, or batt, or
> what?
> If my battery is dying a slow death would it keep losing it's charge, so
> that
> if I check it in a few hours it would be even lower?
> 
> Oh, and can someone recommend a good replacement battery if in fact
> that's
> what I need?
> 
> Thanks for any help.
> 
> Steve Tatro
> Red/Black '93 with 171k miles
> Cincinnati, Ohio
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