Battery drains after five days of driving

1991 CADILLAC DEVILLE
125,000 MILES • 4.9L • V8 • 2WD • AUTOMATIC
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JAGGER LEES
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After driving my car for 5 days the next morning I went out and the battery drained. I have changed the battery, the alternator and check the battery draw check the volts it's showing all good, there's no lights on. I took it to a mechanic that they said there's no draw.
Jan 11, 2022 at 2:45 PM
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SQM
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Hello,

If the alternator is charging the battery properly and the battery is good. Then the only explanation is that there is excessive parasitic draw (current drain) on the battery.
All electrical circuits will have some amount of draw, however when it becomes excessive it will drain the battery fast, many times it will drain it completely overnight.

This vehicle should have about 25 milliamps of parasitic draw, which is considered normal.

To determine what is causing the draw you will need to use a multimeter and check for the draw at the battery while removing different fuses for different components.

Here is a helpful video showing what to do:

https://youtu.be/z5F7WpgjaRs

https://www.2carpros.com/articles/car-battery-dead-overnight

Please let me know if you have any questions.
Thank you.
Jan 11, 2022 at 9:48 PM