18650 to C and D cell adapters

mrfixitman

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Apr 16, 2023
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I have used 3 or 4 A123 3.2vdc batteries in 3 or 4 D Mag-Lite I upgraded bulb to match higher voltage. Just flip the end ap spring.
Adapters are not commercially available but some people can easily make them even in their garage with lathe.
Voltage of single Li-Ion is pretty close to 3 cell "D" (Alkaline or NiMH) but for 2D size, you need to make sure your module will take voltage of your new set up.
There has to be PVC the right size to adapt c to d cells.
 

mrfixitman

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I took a Two C cell flashlight and use one A123. All I did was stretch out the spring. 3.2 vdc. Works like a charm. A123 close in diameter.
 

vicv

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Mar 22, 2013
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Btw 2x 21700 is the same length as 3c so no need to make anything conductive for length like with 18650. You just need to take up the windage. It's not much. I used some super thin plastic pipe from a kids toy And make sure they're button tops
 

alpg88

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Apr 19, 2005
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3/4pvc inside 1 inch pvc is a perfect for D to 18650. but you have to cut 3/4 pipe along so it goes into 1 inch. i posted pictures in some maglite thread a while ago.
 

mrfixitman

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Apr 16, 2023
Messages
235
Location
San Francisco
I took a Two C cell flashlight and use one A123. All I did was stretch out the spring. 3.2 vdc. Works like a charm. A123 close in diameter.
I shorted out one of three A123 26650's in a modified flashlight. I flipped the spring and the end reached around and contacted the case through a nick in the insolation. These are powerful batteries and any break in the covering is a possible failure point. I let the smoke out so tape the nicks and don't have the spring too tight.
 
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