Mag-Lite 3-Cell C Size Adapter for 18650 Lithium Batteries

thingiverse

For this adapter, you'll need to machine the front and rear spacers from aluminum or brass based on the given drawing specifications. Three C cell alkaline batteries are replaced by two 18650 button top lithium batteries, which provide a higher voltage output. I've opted for unprotected type 18650 batteries, offering a total of 7.4 volts compared to the 4.5 volts delivered by three C cell alkaline batteries, effectively converting the 3-cell flashlight into a 5-cell equivalent. A LED Mag-Lite conversion bulb purchased on eBay will be used. A video explaining the design, demonstrating assembly and installation into the Mag-Lite can be found at https://youtu.be/6BcD2K7EjpE. The 3D printed adapter securely holds the batteries and spacers in place for easy insertion and removal from the Mag-Lite, also serving as an insulating sleeve. The adapter, combined with front and rear spacers, provides a positive contact with the Mag-Lite switch contact and tail cap spring. C cell alkaline batteries are rated 8000mAh but tend to be expensive, unreliable, and prone to leaking, which can damage your flashlight. In contrast, 18650 batteries are rated 3000mAh and will last longer when running an LED bulb. I expect the 18650 batteries to hold their charge for six months or more when unused and stored on a shelf. I've designed adapters for 2C, 2D, 3C, and 3D Mag-Lite flashlights, with each adapter listed separately on Thingiverse to avoid confusion. To explore other options: Mag-Lite 2-Cell C Size Adapter for 18650 Lithium Batteries can be found at https://www.thingiverse.com/thing:3465819. Mag-Lite 2-Cell D Size Adapter for 18650 Lithium Batteries is available at https://www.thingiverse.com/thing:3473302/edit. Mag-Lite 3-Cell D Size Adapter for 18650 Lithium Batteries can be accessed at https://www.thingiverse.com/thing:3473442/edit.