Glanced at a listing for one on ebay that had a power adapter pictured, said 24V 3A. Not sure if it's the right one (there were actually 2 in the picture), but if you can find photos of similar units or can find a manual, finding the input voltage for the camera/charger shouldn't be too tricky, at least. Then I'd look around for batteries sold as replacements and look to see if the voltage/capacity is ever specified.