I've only tried the carrier with the included Defiant batteries and I don't own any eneloops (yet). Are you saying Eneloops won't fit into the carrier or that the carrier with eneloops in it won't then fit into a particular flashlight? I'm assuming the first option. I'll try to remember to measure my batteries.
Ok NightCrawl, I measured my cells. The original Defiant alkalines are the smallest I have at 14.10mm and if I push them in toward the center of the carrier they will barely slide into my 2D maglite (would need pushed back out from the front somehow to get them out though). My Energizer 2300mAh's measure 14.35mm, my Sanyo 2700mAh's measure 14.45, and my cheapie Harbor Freight 2000mAh's (manufacturer rated) measure 14.40mm. The carrier by itself (empty) slides right in! I guess if the inside of the carrier could be trimmed somehow to allow the cells to move inside more than it would work well without any boring to the light body.
it’s worth trying to trim the carrier, but in an old 4AA 5mm LED light I have it didn’t work. With alkalines, the holder slides right in. With any of my rechargeables it doesn’t, even after I trimmed the holder to a shadow of its former self. Bit of a pain but a useful home for old alkalines.