I had no idea anything was wrong until the car had a dead battery the other day. I jumped it and it was reading in the 14v range while running so it seems to be charging fine. But then I started checking the voltage the past few days and it would be around 12.6 or so when I shut off the car and then the next morning it was reading in the 12.2 range, enough to start the car though, so maybe it has been that way for a while and I didn't notice it. Last night I just disconnected the battery to see if it would drop on it's own and it was reading 12.58 when I disconnected it and only dropped to 12.47 this morning. Should that have even dropped at all though if it were disconnected? I have other batteries in the garage from my boat and trailer that sit for months and barely even drop .1 volt in that time. The battery is only a year old. What should I check next?