Mag-Lite 2-Cell D Size Adapter for 18650 Lithium Batteries

thingiverse

MagLite 2D Cell Adapter for 18650 Lithium Batteries To build this adapter, you'll need to be able to machine the front and rear spacers from aluminum or brass, using the dimensions provided in the drawing. Two D cell alkaline batteries are replaced by one 18650 button top lithium battery. I've used unprotected types, which provide 3.7 volts compared to 3 volts from two D cell alkaline batteries. Currently, I'm using a 4.5 volt 3-cell Mag-Lite bulb, but I plan to replace it with an LED. LED bulbs are available on eBay and are expected to be the preferred choice. The following video explains the design, demonstrates assembly, and shows installation into the Mag-Lite: https://youtu.be/6BcD2K7EjpE The 3D printed adapter holds the battery and spacers in place for easy insertion and removal from the Mag-Lite, while also acting as an insulating sleeve. The adapter provides positive contact with the Mag-Lite switch contact and tail cap spring. D cell alkaline batteries are rated at 12000mAh but tend to be expensive, unreliable, and prone to leaking, which can ruin your flashlight. The single 18650 battery is rated at 3000mAh and will last longer than alkaline D cells when running a LED bulb. I expect the 18650 to hold its charge (unused) for 6 months or longer. I've designed adapters for 2C, 3C, and 3D Mag-Lite flashlights, with each adapter listed separately on Thingiverse to avoid confusion. Other available Mag-Lite adapters include: MagLite 2-Cell C Size Adapter for 18650 Lithium Batteries https://www.thingiverse.com/thing:3465819 MagLite 3-Cell C Size Adapter for 18650 Lithium Batteries https://www.thingiverse.com/thing:3473408/edit MagLite 3-Cell D Size Adapter for 18650 Lithium Batteries https://www.thingiverse.com/thing:3473442/edit