The nominal battery voltage is 12.6 volts. In order for the battery to be charged, a current has to be sent through the battery in the opposite direction of when it discharges. That'* just another way of saying that the voltage has to be higher than the battery'* voltage. Mid 14'* would be about right for a charging voltage, depending on the condition of the battery'* charge. 15 volts would be getting a bit high, and 16 volts could indicate a problem in the charging circuit/voltage regulator. Usually, the voltage meter in the car is sort of a good approximation of the actual voltage.
Black 2000 SSEi, Silverstar Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, drilled 180 degree thermostat, Intense FWI, PCM, shift kit, and 3.4 Pulley. Solid front mount.