I use NIMH rechargeable batteries in my detectors. Using them is much cheaper than buying alkaline batteries. I have been using the same Energizer 2500 mah batteries for 17 months. Here is a link for buying rechargeable batteries.http://www.thomas-distributing.com/index.htm

My detectors use a 12v power supply (battery pack) that uses 8AA - 1.5v batteries. When using the rechargeables the fully charged pack reads 11.2 v. This is fine and the detector runs great because the detectors have voltage regulators and actually run on 8v. The advantage of my modified battery pack is it uses 9 NIMH batteries for a full charge voltage of 12v giving me the same operating time as using alkaline batteries. Never use 9 alkaline batteries in this pack because the voltage would be too high.

To open the pack, slide a knife between the sliding cover and case and pull off the door. picture 1

Sand down the small bump. It makes the door easy to get off for charging the batteries. picture2

Take out the contacts. They just lift out by hand.picture 3

Remove the two ribs to make room for the 9th battery. You can grind them out with a dremel tool or burn them out with your soldering iron. Then remove and cut the contact. picture 4

Replace split contact and solder to battery holder. picture 5