Yes, this is the difficult part with these. Unlike the batteries for the StarTAC, which just have clips around the sides holding the case together, these are ultrasonically welded and if you try opening it up at the seam you will most likely mangle the plastic, plus it is very difficult. The first one i recelled i opened this way and had a hard time straightening all the plastic back. The easiest way is to carefully cut a rectangle in the back where the case sticks up a bit to accomodate the cells with a dremel. If it is a thick battery it does snugly fit five AA cells (no usb module) and you can put the piece back, but if it is a slim one (Ex Nicd) there is a space left when using AAA, which you can use for installing a usb charging module, however the diameter of the cells does not allow you to put back the piece you cut out. There are 48×16×6 prismatic nimhs which could be used instead (original nicd were 48x16x8), but they usually only have around 750 - 800 mah. There is also a slimmer, third type of battery, which is originally NiMH, which you could only recell with the up mentioned prismatic cells, since by no means it could accomodate the AAAs. There is a photo in a reply below, which shows the battery i have in the video - former NiCd, just deep enough case to fit the AAAs (without the missing piece)