12V battery discharging - '05
 

In the last month my '05 has had a nearly dead 12V battery on two occasions. The first time was after it had sat for 11 days while I was away. I thought maybe it was because I had a couple devices on chargers (flashlight, two-way radio). It took a jump start right away and worked fine for the next couple weeks.

This time it sat from Wednesday afternoon until Sunday night. Same deal. This time I just put the battery charger on it and it started right up.

The 12V battery in this car was replaced just over two years ago. By comparison my '06 still has the original 12V. I don't think it is the fault of the battery per se but I also don't think the couple things I have plugged into the cigarette lighter should be killing it this quickly either.

The odd thing that I noticed both times this has happened is that the interior light won't work at all even after the car is running again. After a while it works again.

Any suggestions where to start? I don't want to run out and buy another $120 battery nor do I want to bring it in and have a tech start guessing at it.

Just over 80k on it now. Needs tires before the winter. Car is flawless otherwise.

Thanks

Re: 12V battery discharging - '05
 

Use a multimeter to test the battery voltage with the engine running. It should be at least 13.8 volts. To check for a battery drain. Disconnect the battery cable and put the multimeter set on amps in series with the cable and battery post. Any drain should be a few milliamps or less. If more, something is draining it. You can also have a battery tested for free at many auto parts stores.

Re: 12V battery discharging - '05
 

Keep Disconnecting battery connection whenever you go out of city and don't use that car.