Battery going dead overnight

200 Volvo S70, 177K. I recently bought this tank as a used, one-owner vehicle, and it’s quite nice. The problem giving me the most trouble right now is that the battery has been dead in the morning two days this week. The first time, I chalked it up to unfamiliarity with the vehicle and figured I’d left some gadget turned on; but this time, I checked everything before leaving it. I also had the battery tested, and that checked out fine.

I don’t recall the weather conditions prior to the first time, but it did rain buckets all day yesterday, so I can accept that moisture may be playing a role. Any advice on what (and how) I can check to find the leakage?


You probably have a “parasitic battery draw.” This could be as simple as a bad glove box switch or something like that leaving a light on that you can’t see. Or it could be a more complicated issue. The starting point is to find out what continues to draw power with the car and everything off. Here is a basic guide:

  • or take it to a trustworthy local shop and tell them you think you have a parasitic draw on the battery and they will find it.

FWIW, I pulled out the cell phone charger from the cig lighter last night, and the car started fine this morning. I’ll check the wikihow link though. Thanks for that.

Time for new battery IF you think cell phone charger is cause of dead battery.

Some cigarette lighters are hooked up to 30 circuit, so leaving a charger hooked up all night could kill the battery

I do know that the cig lighter outlet is switched. When the key is off, the power to the lighter is off; so I don’t really think that’s the problem. Still, it hasn’t happened again, so that’s a good thing.

First off, are you very sure the battery charge is low and there isn’t a connection problem to the battery causing this issue? That will make it seem the battery is dead. If there is a current drain then following the proper test procedures for that kind of thing, and as previously mentioned, should lead you to the problem.

Even if it is a 30A circuit a cell phone will not draw anywhere near 30A. Unless the charger is bad, and even then I would think it would melt itself down, revealing an obvious problem.

When you say the battery is dead in the AM, do you mean when you turn the key to “start” it only clicks, but doesn’t start? Or is the battery actually totally dead. No lights on the dashboard, etc? If it is the former, but not the latter, the problem could be something to do with the starter circuit or starter motor rather than the battery.

A 200 Volvo. Cool. That would make it 1,814 years old.

Seriously, you either have a parasitic drain, the battery is shot, or the alternator is shot.
Many parts stores will test both the battery and the charging system for free. You might want to have that done.

If the charging system checks good, the other thing you can try to isolate the parasitic drain is to remove the fuses for all the unnecessary circuits and see if that helps. You can put them back one at a time, and when the problem returns you’ll know what needs looking into.

Ha. No, my Camry was 1,814 years old when I junked it; but this is a 2000. And, knock on wood, I have not experienced the dead battery issue again, not even on the sub-zero mornings. I’m still gaining confidence in “The Tank”, and I’m hoping the issue was a fluke due to my unfamiliarity with the car’s features. I must have left something turned on, but we’ll see. Thanks all.

It’s good to hear it was a fluke. It could have been as simple as having left a door ajar.

But I have to ask, are you driving it sufficient distances every day to recharge the battery? If your driving pattern is just a mile or two to the store and back, the battery will run low and you might want to consider a trickle charger.