Hi all,

My wife called me at work yesterday and reported that the car was sluggish to start a few times during the day, then wouldn't start at all that morning. I gave her instructions to charge the battery (we have a smaller charger that does well, but takes a while). She said the charger was blinking, which meant it was working. When I got home, the charger had a solid green light and the battery was at 13-ish volts.
We discussed what could have happened, so I did some tests with the now fully-charged battery:
1 - Current draw: I switched my multimeter to the 2 amp setting and with the car fully off, removed the negative terminal and put one probe on the battery, one probe on the cable. I got an initial spike of 200mA, which trickled away to nothing. I chalked that up to the radio memory waking up when I connected, but then it's not on, so it disconnects and goes back to sleep. Either way, for all intents and purposes, there is zero to negligible current draw on the battery.
2 - Running voltage: Just like the manual says, 14 volts while running, so the charging system is working.
3 - Further troubleshooting: I went in the house, looked up a few things on the internet, double-checked everything I could check with the Bentley book. Tested the voltage again with the negative terminal removed, and with it on. I got the same reading, but the battery had dropped to 12.62 volts. Hmmm...
4 - Battery load: I did as the Bentley book said and ran the headlights for one minute. Testing afterward showed the voltage had dropped to 12.4 volts.
At that point, it was time to hit the sack, so I re-connected everything and vowed to look at it today, with the suspicion that I might come home to a dead battery.

So I came home and tested the voltage; solid 12.4 volts, so it hadn't dropped in 24 hours, which made me suspect the battery was still good. I did the battery load test again, and the battery went down to 12.25 volts. At that point it could still start, so I started it and let it run for 5 minutes. Running it showed 14 volts, and after I switched the car off I tested the voltage; it was back up to 12.4 volts. I suggested to my wife that maybe she had left the lights on (which she never does) or some other negligent behavior that I have been prone to in the past. I then suggested we grab the Jump 'n Carry just in case, and go for a spin across town, stopping at a few points along the way so I could check the progress with the multimeter.
Here's where it gets interesting...

She started the car and noticed the Charging System and Brake Failure lights remained on. I said to turn it off and back on again, thinking it was a fluke. Second start, she gets the "RRrr RRrr" of a low battery trying desperately to push the starter to life. I checked the voltage: 11.29 volts! What? We went back inside and discussed what it may be, and I eventually wandered out and checked the voltage again. 12.38 volts! What? I grabbed the Jump 'n Carry and started it back up. No extra dash lights, and the running voltage was 14 volts like it should be. I let it run for a few minutes; more than 2, but less than 5. I checked the voltage again: 13.12 volts! WHAT?

OK guys, I'm clueless here. I have one or both situations here:
A bad battery that is capable of not only running low in the span of 2 shopping trips, but also maintaining a charge for 24 hours, then dropping to unusable levels after 2 extra dash lights came on, then jumping to new battery voltage after ~3 minutes of running the car when 5 minutes of it only pushed it back up to marginal,
OR,
the Alternator and its attendant voltage regulator is charging intermittently.

I don't particularly savor the idea of paying out for another battery that may or may not be the culprit, nor do I particularly want to bust my knuckles replacing the Alternator, but I think that might be the problem.
What say you? Are these the symptoms of a dying battery, or a twitchy charging system?

P.S. I saw the other "starting issues" threads on the main page, and I did do a cursory check of the relevant wiring. Everything is OK as far as I can see, but I guess I can't rule it out.

 

My 1st question would be how old is the battery. 12.4 v is not a charged battery. If older then 5 years then get a new one. If voltage is 13.8 - 14.2 while running then the alternator is working. Remove the battery and go have it load tested .

 

Sounds like bad cells in the battery. Get it checked.

 

You have a bad battery.

 

as jagtoes and act1292 have said get battery tested. in meantime you could also check that your grounds are clean/tight.
otherwise you have already thought of the voltage regulator being intermittently not working properly...

 

OK, the opinions seem unanimous; battery is the most likely culprit. I'll take it to Napa and get it tested, but just to ease my wife's nerves I'll probably just get a new one. This one is only 2-1/2 years old, BTW, but when I had it in the other Volvo (RIP) I ran it down a couple of times accidentally leaving the headlights on, so that may have toasted it.
Lesson learned...

 

why 'just get a new one'? get it tested first then see. for whatever it's worth i had a napa battery fail miserably on me which wasn't that old. very good performance out of the interstate i got to replace it..

https://volvoforums.com/g/picture/13491624

 

+1 on the Interstate batteries.

 

I trust you have and use a battery terminal cleaner - the inside and outside wire brush thingy. Bad connections can be erratic and frustrating.

 

I followed everyone's advice and got the thing tested before I made the jump. The guy at the counter said it was bad, and the numbers he pulled from the tester thingy indicated probably a cell or two had gone bad. I'll take the blame for that one, having run it down one too many times.
With the prorated warranty on the old battery, I walked out with a AAA battery with a 3-year warranty for less than 30 bucks. I ain't complainin'...
Thanks all!

 

Try facing down an anxious wife who just wants the car to start when she's ready to take the groceries home...
I convinced her that putting a new battery on a bad system would have been just as bone-headed as tearing apart the alternator when the battery is the problem, so yep, got it tested first.

 

ha i hear you! i've got one at home as well...
saw the test came back couple cells possibly out. that would certainly explain your symptoms, and big bonus you don't have to fool with the alternator like i had to few weeks ago..ughh.
believe you did the troubleshoot in exactly the right order.
$30 is an incredible deal these days early xmas present for u ! be well!

 

I would check the new battery voltage and also put it on a charger overnight. Remember these sit on a shelf for a while and lose some of the charge. An alternator is not what you want to charge the battery with. Just a suggestion

 

believe AAA batteries are made by East Penn these days...good co.

 

I hear ya, but the guy said it was manufactured this month, so it shouldn't have sat for long at all. It started the car right up too, no hesitation like I used to get buying Wal-Mart batteries. Ugh. Never again.