My car (2007 Lincoln MKZ) battery dies if I leave the car parked for two days or more. I’ve had this problem for a little over a year now. I’ve been dealing with this by disconnecting the negative terminal of the battery when the car will be parked for awhile. When I do this, The car can be parked for a long time and will start right up when the battery is reconnected. I brought the car to a mechanic and they performed a parasitic draw test by placing an ammeter between the battery terminal and the battery cable. They said the car draws .022A after waiting 30 minutes to perform the test. They also load tested the battery and said it was fine. I repeated parasitic draw test myself later and the test had the same result. I took the key out of the ignition and let the car sit for 30 minutes before reading the measurement on the ammeter There was .022A or less of current draw from the car after the car was allowed to rest for 30 mins. I brought my car to an Advanced Auto Parts where they used they used a device that tests the battery, the alternator and the starter all at once. All three checkout fine and I’ve uploaded a picture of the results. I’m at a loss as to what the problem could be. Does anyone have any ideas? Thanks in advance!
You should wait at least an hour to make sure all computers/modules go to sleep before performing a parasitic current draw test.
The only thing I see, the battery voltage at 12.41, if that is right after shutting the car off, it’s on the low side.
I’d like to know what the battery voltage is after sitting for a couple hours.
12.3 volts after sitting for a couple hours is time to start watching for sales on a new battery.
Any lower it’s time for a new battery.
If you have a meter that records peak amps in memory and leave it hooked up for a long period of time you may find that something intermittently activating at random . I had this happen from a faulty rear windshield wiper motor on I don’t remember what.
I had a similar problem with a 2002 Chrysler Town and Country. Battery tested good and parasitic draw tested good.
Battery would go dead overnight. I came home and my wife had driven the van. when I walked by it, I heard the radiator fan start up. The engine was cold to the touch. When I asked my wife how long the van had been sitting she said 4 hours.
I replaced the fan control module and all was well.
\You may have something like that going on but the trick is finding out what.
What is the symptom when the car will not start? Sluggish starter motor and engine turning over slowly?
Headlights dim with key on? Or stone silence? Just wondering.
The .022 should not be a problem but how old is the battery? I have a distrust of battery capacitance testers as several facilities over the years have sworn that a known 100% garbage battery was stated to be fine based on the use of those testers. Best method is to apply a load.
One of those “fine” batteries would go no higher than 7 volts after being on a slow charge all night. Two known dead cells will do that…
If the battery is fully charged, remove the fuel pump relay or fuse while a voltmeter is connected and crank the engine over for 10 or so seconds. The voltage should remain preferably in the mid 10s. It if drops to 10.2 the battery is on shaky ground. Dropping into the 9s means it needs to go.
Another case of the old fashioned test being the better test: if the battery caps come off, the state of charge of each cell can be tested by measuring the specific gravity of its fluid.