Maglite 2-Cell D Size Conversion for 2x18650 Li-Ion Batteries

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This is a simple upgrade of an old 2-cell D-size Maglite flashlight to an LED lamp and two 18650 Li-Ion batteries (7,4 V). Printing a very straightforward battery holder for the slender but longer 18650 batteries is step one of three. Step two: Providing a conversion LED lamp for the P13.5S socket, taking 7,4V from two x 18650 batteries. I discovered an affordable option with a 3W CREE-LED for 4-12V on AliExpress. Search using these parameters: P13.5S LED conversion. This one fits snugly into the Maglite. Step three: Modify the tail cover of the maglite. Since 18650 batteries are longer than D-size cells, the spring in the tail of the flashlight must be installed inside the tail cover instead of onto it. See pictures. Use a vice to tighten the spring. Ensure it has contact with the minus-pole of the batteries. If your Maglite is colored, remove the color under the spring for contact. Utilize a meter to verify everything has electrical contact. Of course, you'll also need two 18650-type Li-Ion batteries. Make sure they have a proper plus-pole tip (not too flat for contact inside the Maglite). Remember that you'll also require any charger for the batteries. This upgrade will give you a significantly brighter flashlight than before (two last pictures to compare). However, since the reflector is not optimal, it won't be as good as a genuine LED-flashlight.