2001 S60 - Low idle rolling speed, low battery level

[Pennybags]

I had a short drive earlier today, and I noticed as soon as I turned the car on that I was getting very little pull when idling in drive. It's a 2001 S60, so it's rife with throttle body issues and PCV clogs and whatnot, so I'm not even sure what to expect when the car actually works. Normally when the car behaves I can roll at around 10 MPH in drive with no pedal input at ~850 RPM. Today in drive at ~850 RPM it was barely breaking 4 MPH, and almost outright stopped while turning.

I've experienced this before when my alternator failed, but I put my meter on the leads while the car was running and I got a solid 14.00V. I did get a troublesome reading of 12.23V before turning on the car, but it looks as if at least the alternator is doing its job.

Does anyone know what might cause an issue like this?