I like the theories advanced so far, but one more basic thing I would wonder about is whether your 12V accessory battery is not holding a charge well. When ours wore out, the first symptoms were that the car stopped "remembering" stuff (like the clock not keeping time). And that was when the car...
Well, we picked up our Leaf yesterday (15-Feb-2014). MY 2014 S trim in Silver with the charge package.
So far we love it! It's our first car with a backup camera (awesome as backing out of our garage is a bit tricky), USB port or integrated Bluetooth. I was glad of the heated wheel this morning...