Alternator output high? 2012 S60

Herb Goltz · Post by **Herb Goltz** » 30 Oct 2025, 09:50

Hello all:

I have had an intermittent low battery warning on my 2012 S60 T5. As part of some diagnostics, I measured the output of the alternator at the battery, and was surprised to see 15V. Is this abnormal?

Post by **chrism** » 31 Oct 2025, 06:24

Hi Herb. From what I’ve read here and there it’s not unusual to see alternator voltages running as high as like 14.8-ish especially if the battery charge is low. The voltage should drop slightly as the battery charges up.
How old is the battery? And does the 2012 S60 have the second auxiliary battery like our 2018?
We were getting the low charge message periodically for about a year but then the starter finally began to sound sluggish so I replaced the main battery. I haven’t replaced 7+ year old auxiliary battery yet. I’m guessing it won’t be long….

Herb Goltz · Post by **Herb Goltz** » 31 Oct 2025, 10:58

Thanks Chris-- things got more complicated when I tried to do more diagnostics-- the hood release cable broke when I tried to open it! I got it to a local independent Volvo shop ASAP to avoid needing a tow. They got the hood open and jury-rigged wire loop pulls to both hood latches (the bumper has to come off to replace the cables, they say they do both cables and latches to avoid comebacks, but $$$$ for parts and labor). I am going to leave it for now, and will order cables etc for a DIY fix once I research the job. I think the low battery issue is resolved-- there is a battery monitor that needed to be reset-- I replaced the battery in the spring with guaranteed used battery, but didn't know about the need to reset the monitor. This changes how the ECU communicates with the charging system. We looked at alternator output and did a load test on the battery after reset, which were OK. The 2012s don't have the aux battery. These P3s are a different beast-- I am a lot more comfortable with my P2s...