It may be getting tired--you really need a "load" test to find out for sure since voltage is only part of the story. After sitting for a few hours a fully charged battery will be at 12.6 V. With the alternator charging, it can be anywhere from about 13.5V to 14.5V so that gets a bit confusing as well. 35 minutes on acc position sounds short unless you were cranking the stereo.I think my battery may be on it's way out, it died after having the ACC on for <35 minutes. (not able to start).
Before normal running was reading 14.2 V
Now it sits between 13.2 - 13.8.
I'll have it checked but I am curious about others.
The charging voltage doesn't indicate much other than your alternator is charging--those numbers are not unusual. Check it after sitting overnight with the key on but not running. It should be about 12.6. If it is 12.2 or less, it is probably bad.I've been having issues at startup and battery wouldn't start the car until the 3rd try tonight. Voltage at startup climbs from 14.6 to 15.1 then settling back to 14.5 after running 5-10 mins. Does this sound like a bad battery? I'm taking it to the dealer day after tomorrow and would like to know if anyone's run into this before. Appreciate any help you guys can provide.
I just checked my battery as you suggested and it read 11.9 volts after sitting for two days. My dealer has already told me it passed their tests, therefore they could not replace it under warranty. It has already failed to start the car once and the battery is only a little over two years old, assuming it was fresh when installed in my new STS. I am inclined to replace it with an Interstate MTP H3 which fits the STS and is highly rated. Firestone quoted me $135 plus change out the door. It may be worth it for the peace of mind. What do you all think?The charging voltage doesn't indicate much other than your alternator is charging--those numbers are not unusual. Check it after sitting overnight with the key on but not running. It should be about 12.6. If it is 12.2 or less, it is probably bad.
I am not convinced it is due for a battery based on the "good health" report from the AAP diagnostics. In the "won't crank" situation, I get no message on the DIC. Thanks for the reply.If you're due for a battery soon, you may as well replace it before throwing money at other diagnostics. Just a hunch, though, it seems like you've got an electric gremlin that intends to feed on money.
Maybe someone whose battery has gone dead can tell us if the car explains that with a message or if you just get no starter action. I can't recall from the one time it happened to me what (if anything) was shown on the DIC.