White's 3900/D PRO PLUS Metal Detector Battery Holder Replacement

White's 3900/D PRO PLUS Metal Detector Battery Holder Replacement

USE AT YOUR OWN RISK

My original battery compartment used D cell batteries (4 x 1.5v = 6v).  In college I decided to go eco with all rechargeable in my life and taped 4x NIMH batteries (4 x 1.2v = 4.8v) together and rigged the metal detector to work.  I finally decided now that I have a 3d printer I could make a replacement power supply and use 2x 18650 batteries (2x 3.7v = 7.4v).  Concept was easy get a 5v regulator and tap off of some batteries.  This is the result.  

Parts you will need:

• 2x M3 Long heat set
• 2x M3x20 Hex Socket Head Cap Screws
• 2x M3 Fender Washers
• 2x M3 Washers
• 2x M3 Nylock Nuts
• 4x M3 Short heat set
• 4x M3x8 Hex Socket Flat Head Countersunk Bolts Screw
• Parts for Additional Print
• 5v regulator

Additional prints:

• 18650 battery holder basket-v1_2.stl

Building:

• Insert short heat sets in back of model
• Insert long heat sets inside end where the +/- power studs will go
  • Screw long screws and fender washers in the long heat sets for terminals.
• Screw additional print to this model
  • assemble additional print to hold batteries
• Wire batteries in series
• Connect to voltage regulator
  • wrap output of voltage regulator outputs around the proper terminals use washers and nylock nuts to keep wires from disconnecting from the terminals
• Put in metal detector. 

WARNING this works on MY metal detector.  If I did it right, you cannot put the battery pack in backwards like the original.  The contacts will not make connection.  Not exhaustively tested.