Dunno what caused it but took it back to auto parts store and the put some tests on it and it came back 900amps, 200more than its suppose to have, he said it probably has one of the cells shorted out. This was the RED TOP Optima. So, they replaced it under warranty and I went ahead and paid the diff. for the YELLOW top. Its what I shouldve gotten in the first place. I knew something was up with it. I went down the other day and it was DEAD, I mean DEAD DEAD, dome lights were barely lit. I did a volt test and it was aroun 9volts. Luckily ive got dual batts and jus hit the button to start the truck. My Alternator was charging both batts fine. With truck running I had 14.7 volts. I drove it for an hour, came home, turned it off and it would read 12.4 volts supposedly that is only 60% charged. Here is a chart someone gave me: 12.7 - 13 v = 100% 12.6 - 12.5v = 80% 12.3 - 12.4v = 60% etc. etc. etc. So anyways, that was interesting, thought id jus share.