Strange. I use a wall adapter too, but my batteries never take longer than 3 hours, but I had similar issues when I was charging from my computer USB port--lights blinking intermittently, long charging time.
It just might be a bad charger, those lights sometimes malfunction. If you're using Joyetech chargers and the connections are clean, I can't think of another reason. How old are those chargers? Can you contact your vendor and ask for a replacement? If not, and if money is no object, I'd get another charger. It's good to have a spare, anyway. One never knows with those things, they often malfunction or die.
