I recently had an even easier time changing the rechargeable battery in some mini Christmas lights. The unit was a solar panel in a box held by 4 screws. Took them out, and it was a regular AA nimh just slotted in there. Changed it out and the thing worked again.

I wonder how many people just chucked the unit when the battery wore out.

I just bought the Steam Frame, valve's new VR headset. After hunting for a USB port on the paddles i was shocked to find how eaily it is to replace thier batteries. They are Duracell AA.