This has been a head scratcher for me and everyone I have asked about it.

The first time I had this problem was back in November. I went out to start the truck and it cranked, but just didn't have enough juice to fire. I let it sit for about 20 minutes, that sometimes lets the battery recover. I go back out and the remote won't unlock the doors. Completely dead. I had to hook up jumper cables for about 20 minutes to get it to fire. No problems until about March. I drove to the store, parked and left the radio on for about 15-20 minutes. Go to start and nothing, just a click. After that the radio won't turn on, interior lights are dim. This time I disconnect the battery, jump directly to another car then reattach the battery. Maybe not the safest thing, but it was cold.

The battery is fairly new, bought it back some time around September. Every connection to the alternator and battery is tight and free of corrosion, same is true for every ground I can find. I have occasionally saw the volt meter drop down to 12 while driving, making me think it's a charging issue. But what's the cause? It's so infrequent I can't pin anything down.

The truck is a 2007 chevy 1500, new body style. 5.3.

I'm about to put another battery on with a relay between the two so I can run off either battery or both just so I don't get stuck somewhere, but that's just a bandaid to the problem.

Any guesses?