I converted my Vaquero single 9v battery to a 6 cell AA battery pack(9v) for longer battery life(Photo shows AA battery size and battery from inside 9v,one of six).-first I stripped a dead 9v battery (duracell has strips attached)for the terminal end with the thin connecting strips attached(photo) so i could solder wires to the terminals.I made,out of wood(photo),3 thin pieces glued together so i could grove one for the wirers to fit into) a block the size of the 9v battery and added the new wires and battery terminals so it would fit into the battery compartment as a 9v battery would.I had to notch the battery cover for the wire to exit the compartment(you can get a new one from Tesoro).I stripped an old low voltage transformer (wall plug type) that was large enough to hold the new 6/AA pack.Any plastic housing will do.I used a 3/4 inch plastic pipe clamp to fasten the housing to the upper arm ,just below the stand.I added 9v battery terminals to the end of the wire and battery pack for easy replacement of the batteries.(watch polarity.it reverses when two 9v terminals/wires are plugged together).A few velcros hold the wire to the shaft...Yes,this does add a little weight to the machine but the batteries will last a lot longer...6AA battery holder and 9v battery terminals and probably housing at Radio Shack,on line..3/4in pipe clamp and thin wood strip at home depot.Ralph