Power Drains While the Car is off. PLEASE HELP!!!!

[ruddycreek]

So my car can jump and start properly, and if it's running, it'll run all day, so I know it's not the alternator, but if I shut it off, the battery drains FAST! (Like in 15 minutes) I've bought more than 1 new battery, so I know it's not a faulty battery. There are no fuses blown, so I don't believe a seized fan motor or something is to blame. I've had it checked professionally as well, and the result was basically that something was drawing a large amount of power, but I don't know what. Please help.

This is on a 2002 Mazda Protege, with a naturally aspirating, FS-DE motor. I have also disconnected the stereo to try and rule out that possibility.

 

[cougar10agREDUX]

why do you say the battery is drained? batteries have a reserve capacity of way more than 15 minutes. if multiple batteries are completely dead in 15 minutes, then the alternator may not be charging properly. with the engine running and turning on all electrical accessories, does everything seem to dim?

or do you think it's dead because your car will not start?

 

[dhodory]

Have you checked to ensure that your leads are tightly affixed to your terminals? Had this exact issue and basically, every time I charged the battery or jumped it, it was fine. However, what was happening was that while driving my alternator wasn't charging my battery because of a poor connection to the battery.

Just something to consider.

 

[goldenboy88]

To add onto what dhodory said, make sure to clean the terminals as well and check for any corrosion on the other ends. I've also seen this happen for corroded leads to the starter after the battery leads were cleaned.

 

[Jeezus]

Take a multimeter and run the leads across the battery terminals with the car running (Multimeter on DC voltage). You should have somewhere between 14-14.5V. If less, then the alternator is not charging.
Turn the car off, and remove the negative ground cable from the battery post. Turn the multimeter on the highest DC Amperage, and put one lead on the battery negative terminal, and the other on the negative cable. You should only have a .010 amp (10mA) draw, for the clock. Anything over 50mA IS a grounding issue. If you only pull 10mA, and want to be super sure, tap the fuse boxes, wiggle the doors(but don't open, the interior lights will come on), etc.

If you have more than 10mA draw with the car OFF and SITTING, come back.