Nealoc187

iTrader: (23)

I'm starting to wonder if the alarm, or something else wired improperly, is drawing significant current off of my battery whilst the car is off, or if this is another alternator problem with weird symptoms.

I bought this car about a month ago with a very strong battery in it. The lights would dim pretty significantly when i turned on the fan, when the RPMs went low, etc, and it soon became apparent that the alternator was bad. The car would still crank over just fine however, the battery seemed strong. The final nail in the coffin was that one day i warmed the car before going to work. When I came back out, after the car had been idling for 10 minutes or so, the lights were extremely dim, the tachometer wasn't even registering any RPM, the RPM was audibly very low, the car was struggling to stay alive. I tried to rev it up, and the car just died. Next day I put in a new alternator. This was 2 weeks ago. Car has been fine up until the last 3 or 4 days.

Now, every time I go to start the car, the car struggles to even turn over as if the battery is weak. Keep in mind this battery was able to crank over indefinitely 3-4 weeks ago, with no signs of any trouble at all. Even after the car is warm, if I shut the car off and restart it, the battery does not seem any stronger (as if it's not being charged by the alternator perhaps?). This would lead me to believe that the alternator on the car is bad again, however the symptoms are totally different from those before. No appreciable drop in RPMs when turning on the fan, defrost, etc. Just very slow cranking.

This to me indicates a battery which is dying, but wouldn't a good alternator charge it at least somewhat during the course of a drive to work? This doesn't seem to be happening. Its gotten so bad that I'm having serious doubts about whether or not I'm going to be able to get the car started in 2.5 hours when I go out to leave work. Any ideas?

Hrap

Two things come to mind: 1) check your battery cables to ensure that there is no corrosion or rust, at both the battery terminals as well as where the cables terminate (the ground cable is a good candidate for trouble), and 2) measure the no-load current drain on the battery by ensuring that everything is off, doors closed, etc. and putting an ammeter between the - terminal on the battery and the cable to ground. No load current drain should be small - 10ma or less.