Basically, the car will not start if I leave my lights on (or the doors open for more than 10 minutes) when not running.

The battery reads a full charge after I turn the car off, but if anything electric is on, the battery drains super fast, and the starter turns too slowly to start the car.

The battery is two years old and I just tested it a couple of months ago. Could this be a problem with the alternator/ charger or a grounding problem?

 

Car batteries don't like to be constantly drained. You can get away with jumping it a few times, but more than that it will start to lose charge fairly quick... especially if it is a cheaper battery.

What does your voltmeter show at idle? At driving speed? Have you taken it to your local parts store to have them do a battery / load test?

 

+1 ^^^^

Sounds like it's not charging properly or you have a constant drain when the car is off. Both can be tested. I always recomend replacing the battery cables for a new-to-you car unless they look minty fresh.

Batteries need to be tested with a load on them. I had an intermittant battery that read fine and charged fine with the alternator on my Jeep but when I cranked it over it wouldn't even click and yet it read a full charge voltage wise.

 

go to an interstate battery shop. buy a good battery from them and have them test the charging system - should be free. fricfrac is right cables that are corroded will kill you system. then buy a cheap ammeter anywhere. pull the ground strap and with some jumpers (radio shack) put the ammeter in series with the battery. if you show a drain there is part of your problem. if you don't understand "in series" buy a book on basic electrical stuff. what did you test when you tested it. without a proper load test set up you can't really test much.

 

thanks, all!

when I said I tested it, I mean I took it to Advance Auto and had them do it, what do I look like an electrician? haha, though I could probably figure out how to test it myself. that idea about testing for constant drain is good, but I don't think that's my problem...

The car can sit without running for days and start up beautifully, just as long as no electricity is being used during that time. HOWEVER - if I leave my radio (lights, doors open, ect...) on after turning off the engine, the car can take about a minute of that, tops, before starting becomes an impossibility.

OH - and the car's voltmeter shows a tick over 14 while driving and when the engine is off, and if it gets down to the yellow because of the aforementioned condition, it will not start.

But I'll get it tested again.

 

Just sounds like a worn out battery to me...

Have you tried putting it on a trickle charger overnight?