What battery voltage do you get during cranking? 9-10v is ok. High means a high resistance point in the start circuit, low means the battery isn't coping.
14v is a little low in warm weather, I'd expect more midwinter. That might be your primary problem. Charge endpoint at 0degC: 15.3v. At 10degC: 15.06v Sounds like either your meter or alternator isn't right.