http://www.cafr.ebay.ca/itm/2-NP-F550-Battery-Charger-for-Sony-NP-F570-F730-F330-F930-F950-F530-Cleaning-Pen-/130972924824?pt=Batteries_Chargers&hash=item1e7e983b98 These are cheap batteries that I use they have protection circuit board inside they are easy to open. As you can see they are 7,5 V...