2012 volvo xc60 3.2 awd
Started getting the charging system failure indications. Battery is newer.. Good readings. Installed new volvo factory alternator. Check tightness of pulley, all was fine. I'm still not getting a charge. Died on the way home tonight. (well, went into limp mode, crawled home).

I've been reading that possibly bms needs reset? Car isn't throwing any codes other than the red charging system failure. Any tips would be highly appreciated. Thank you!

 

Last night hooked up to charger at home for a couple hours. voltage was 14.1 sitting at idle for about 30 min. Shut it off and locked car up. Today after work I took it out for a spin lasted about 30 minutes then the charging system failure light came back on. Got it home and it was at 12.5 idling.

I keep reading about this bms reset. Is it possible I need to replace the bms sensor on the negative battery cable? I'm really at a loss here. Alt is working, was bench tested. It's just that the car isn't telling the alt to charge the battery.

 

Have you done the BMS reset? If you replace the battery and do not perform the BMS reset the ECU does not know that you have a new battery and treats it like it is an old battery. This means that it will not charge it properly and the battery will die prematurely. I went through this on our 2017 model after it killed a new battery in about 18 months.
The BMS can be reset with OBDII scantool that has volvo customizations, but there is also a set of control/button manipulations that will work for those without the scan tool. I can post what I did on the 2017, but it may be different for your 2012.

For the 2017, install the new battery.
Turn the ignition on without starting the car - hold the start button for about 5 seconds with your foot off the the brake so it does not start.
Turn the headlights on to the normal low beam setting.
Press the fog light switch six times (rear foglight)
Press the emergency flasher switch three times - this will leave them in the on position.
Watch for the battery icon in the dash to flash three times.
The BMS will now know that you have a new battery and will charge it properly.

If you search google and youtube you can find the process that works for the 2012.

 

When I had my stock alt rebuilt, the shop had put an aftermarket voltage regulator on it. Ordered a new Bosch voltage regulator from RM European Auto Parts and replaced it. All charging issues have been fixed.