One of my cars was doing the same thing up to last week. I would clean the battery post charge the battery and everything would work fine for about two days. I would get a jump and it would charge up and work fine for the rest of the day, even starting under a load like having the lights and everything on. Next day dead againg, or it would start and then a couple of hours later it would be dead. Tested the battery; dead cell. Got a new battery and it has had no problem for a couple of weeks. I am betting on you battery.