Where do I start to find the culprit for drawing down battery voltage when the car is parked?

It is a Optima red-top battery, less than a year old, so I really doubt it's the battery.

In just two days, for example, there is not enough voltage (11.39) to start the car. Just a click from the starter but no movement.

Where do I start?

 

I would guess that you've checked for lights on when they shouldn't be..........the glove compartment sometimes stays on.

Failing that I would take an Ameter and check some current draws by puting it in the circuit where the fuse of choice used to be.

 

Thanks for the reply!

I tried the latter with the two fuse areas, both in the area and under the hood. How much draw is too much? A few of them had .xx V, including I believe, the fog light fuse.

I never thought of the glovebox light, thanks for pointing that one out.

Any other thoughts or followups?

 

Your concern should be directed toward amps not volts when looking for errant devices.

That little light that's in the cig tray between the shifter and the console compartment sometimes looks like it's on when it shouldn't be.

The problem may if fact be the battery still........
I believe that JasonD has a thread about having problems with that exact make too.

If it's unable to hold a charge when you drive it, then when you park it, you won't be able to start it next time.
When you're driving, the voltage meter will read normal because it's reading what the alternator is putting out, not the battery.

You're not wrong in looking for something that is drawing away from the cell but I wouldn't discount the battery either.

Good luck man.

 

Well, the reason I doubt it's the battery is because it starts up just fine during the day and usually in the morning. It's just that once in awhile it'll be dead after a few days. Other times I've let it go a week and it starts up ok.

So it seems like something is staying on sometimes...

So I should check the circuits using the amperage setting on the voltometer I have? I'll try that next, thanks.