The internal battery is replaceable, but although it is not difficult it does need a fair degree of technical competence and electronic servicing tools. The part number of the battery is ML614. The original in my camera was branded 'Sanyo'. The version with surface mount tags is needed. (The cost is around$5.00) It is at the bottom left corner of the main circuit board. The two solder connections are easy to get at with a small soldering iron.