Date: Tue, 10 Aug 1999 20:02:53 -0600
From: Paul Hahn <pfhahn_at_home.com>
To: Mformation <Mformation_at_halcyon.com>
Subject: Re: Battery won't take a charge,
in Mformation #246, Danial Smith wrote :
"I didn't turn over my M6 for a month. When I recently tried, all I
could get was some check lights. A few days later, everything is
drained. The car is new to me (2 months or so), and I am aware of
some past electrical probs. It has a pretty new battery (1/99). The
car also has a clifford alarm."
If an auto battery goes down below a level of about 10v for an
extended period ( hours , not minutes) all sorts of undesirable chemistry
takes place in the cells and the end result is a coating on the plates that
presents a high impedence to current flow so the cells can't conduct
electricity very well , either as an output (power to you car) or an input
(charging current). There are deep cycle batteries that tolerate existing at
a discharged state better than others, but no battery is helped by prolonged
draining of current.
There is some inconspicuous load connected to your battery that is
sucking the life out of it. Possible causes include glove box or trunk
light being lit all the time. Maybe you have an after market alarm system
on the fritz or an electric heater on the locks or windshield washer
nozzles. Connect an ammeter between the negative terminal of the battery
and chassis ground and then remove the ground strap that normally grounds
the battery. Be sure all accessories are off and all doors are closed.
Don't try to run anything at this point or you might ruin the ammeter. unplug
the trunklight bulb.
At this point you should see no more than 70 milliamps of
current. That is .070 amps or seven one hundredths of an amp. you
probably have over 100 milliamps and you need to find out what is on that
should be off and fix it.
If you can't see it , try removing one fuse , read the meter and see if
the current level has dropped to normal. if it has , now you know which
circuit is the culprit. If not , then return the fuse and try the next
fuse. Repeat the process until you figure out the extra load.
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