No, the battery is not being charged- - - -that's normal voltage for a fully-charged battery without any input from the alternator. Each cell produces an open-circuit voltage of 2.1 volts, for a total of 12.6. It takes a minimum of 13 volts to keep a battery charged, and 14 is better. Most regulators cut off the alternator output at 14.7-15 volts several times a second. If you run the engine for more than a few minutes, or use accessories such as the headlights, wipers, etc., the battery terminal voltage will drop very rapidly. Original-equipment batteries on US vehicles are required by federal regulations to be able to run a vehicle with a minimum of accessories operating for one tank of fuel before the engine dies due to lack of voltage. That's assuming the alternator stops charging when the battery is fully charged and is in good condition.
Jerry
