How can I find out what is draining my car battery?

[MiketheGrinder]

It's an old Hyundai SUV with less than 80,000 miles on it. The battery is newish, still under warranty. I make sure to turn everything off, so nothing should be draining the battery. Everything seems fine when my wife or I drive the car once a month or so. But, if the vehicle sits for longer than that it won't start. It's been checked by a mechanic and he couldn't figure out what the problem is. How can I determine what phantom thing is draining my battery?

 

[Sophia]

If I were you I'd take it to another mechanic and have them check the electrical system. Have you tried driving the car several days in a row to see if the battery still drains? It may be that you're letting it sit too long.

 

[Impaired]

The way I would troubleshoot is next time your car is going to sit, go to the fuse box and pull out one fuse. Do this each time until the issue stops. Then at least you can narrow it down to the things on that circuit.

Good things to check are: wires that go through doors and trunk lids. They are the most likely to short out. Look for bare metal showing through the insulation.

 

[Hilander]

The battery could be about to die even if its not that old. I've had that happen.

If something is draining your battery and you have a multimeter you may be able to run down the problem yourself.

Five Signs Your Car Battery Is Dead (or About to Die)

 

[MiketheGrinder]

Thank you all for the great tips and ideas. I'm going to work on it this weekend. You've all given me a lot to go work with which is fantastic!

 

[MiketheGrinder]

I've tested the battery and the shop did too, so I don't think it's that. The electrical system doesn't show any issue when they run it with whatever it is they use, so I don't think it's that. I've started checking the spark plugs, but am not yet finished. It takes a while to unplug and let the vehicle sit.