14V actually coresponds to something called TVG (Temperature Voltage Gassing) or Gassing Voltage. TVG is basically the voltage at which gassing occurs but the heat produced from charging isn't excessive enough to cause plate damage. Gassing mixes or circulates the electrolyte which increases battery by increasing the specific gravity at the top of the battery. Once you get above TVG for extended periods the active material on the plate can start to shed producing internal shorts and reduced capacity.

Steve

'97 Rodeo 5spd. 3.2L SOHC V6 4WD