Sounds like you could have a small voltage drain. Have you tried disconnecting the battery and seeing if the voltage still drops?? If it holds a charge then batt. is fine (its only 6 months old but could be NFG.). If batt is OK then you need to track down the drain. Methodically try to remove one electrical component at a time by pulling a fuse and see if it stops the drain. Have you ever used the Amp setting on a voltmeter? It will tell you if you are drawing amps from the battery.