I have one of these Vosonic VP300 Mp3-cum-card reader HDD based device. It uses a very slim 7.2v Li-Ion battery.
I am wondering if some other battery can be used to replace the OEM ones. The replacement battery has to be the same dimensions because the battery fits in the back between the device and the HDD mount so the space available for the battery is fixed. I am looking at a replacement (probably some cell phone battery) because the OEM batteries aren't locally available in India.