So I want to use the more readily available 18650 to use a 26650 light.
I can do so using a plastic adapter. 18650 + adapter = 26650 ( adapted to D4S )?
Question, will the 18650 suffer a short lifespan using it as a hi-drain pseudo 26650?
Yes you can use a 18650 in a 26650 powered light I used a couple of different 18650 cells in my ft03 light doing a output test, found out using the imren 4200 mah 26650 cell which is a fairly new cell it out performed all my 18650 cells and I have them all except ebay chinese cells