What causes my battery to run down?

JOEL MCCAULEY

MEMBER
CHEVROLET

Battery is good; alternator is charging @ 14.7v on 1997 Chevy Lumina with 108,000. I have a constant 13.78 v draw on the battery with everything shut off. With the positve batt terminal disconnected and a voltmeter placed between the battery terminal and the disconnected positive lead, I show a solid 13.78 v draw. I have systematically pulled every fuse, one by one, disconnected the altenator, disconnected the starter, made sure the headlights and all interior lights are off. To no avail. This problem just started about three-four days ago. Ikeep thinking this is something simple that I am overlooking. ?

2 Replies

KIRB778

MEMBER
1 POST

Have you checked your sylenoid?

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Saturday, December 30th, 2006 AT 3:37 PM

MATHIASO

MECHANIC
1,209 POSTS

Informations given are allways general and not just spesific to your car, The sevice manual of your car give you specific details about the related repair procedure.

Light switches, relays and generator voltage regulators are some very common causes of parasitic drain that can kill the battery over a few hours or few days. Often the problems are intermittent and require tenacity to locate.
Many car manufacturers recommend measuring battery drain with a tester switch connected in series at the negative battery terminal. Follow the drain test procedure in the vehicle manufacturer's service manual.A multimeter with a millampere scale is connected in parallel to the tester switch.
When the tester switch is open, any curent drain from the battery must flow through the mutimeter