[adc]

'11 with OEM battery. Slow to crank in 15F weather. Checked battery quick n dirty with a multimeter.

12.6V resting
14.6 with engine running.

Battery would appear to be ok, is this just due to extreme cold? I would figure with the thin synthetic oil we run in these it would not be as sluggish....

Take it in to Autozone/Advance and get it checked. Voltages seem OK but that's not always the whole story. Now I have the 08 and replaced my original battery at 90+K miles even though it was fine. Never had your issue.