Defiant 51 led host XM-L mod

A couple Christmas seasons ago I became infatuated with Home Depot's 51 LED side clicky flashlight as a potential mod host. Blinded by lust I bought three of the little buggers to have my way with in the Fishguy chamber of horrors (kitchen). What I found was that these lights are Chinese crap at it's finest. Body is thin, threads suck, switch boot is flimsy, and only one of the three was wide enough to accept four eneloops in a carrier. They could be considered a poor man's substitute for a d cell mag but in reality the mods possible with this host are only those possible with a mag and you could get a mag at only four bucks more at the time.

Enough posterior kicking and on with the mod. I've been waiting for hosts and parts for my next big build but wanting to mod so I started pawing through my junk pile. I came up with this 51 led host and some other less than perfect and/or obsolete parts. No sense in putting good stuff into this crap host. Buried with my reflectors I found an SST-50 reflector with some nicks in it and an plain glass lens. Digging in the emitter bin turned up an old XM-L U2 emitter in a not ugly cool white tint. Because I have lost the ability to be reasonable with drive current a BLF17DD flashed with four mode STAR featuring off time memory and moon mode was defiled by placing it in this abomination of a host. A perfectly good noctigon was similarly besmirched. The bezel was previously Foyed for a different build.

The SST-50 reflector is a tight press fit into the head, meaning, use a vice and blocks of wood. The reflector was stippled with clear coat to eliminate any beam artifacts from the nicks in the finish. The interior of the bezel needs some careful dremel work to accept a 50 mm lens.

I used a 1/4" thick chunk of 1 5/16" aluminum rod wrapped in 0.032" copper sheet for a heatsink. Arctic Alumina was used to secure the noctigon to the heatsink. Acquisition of body ground was a bit tricky in this host but was accomplished by soldering the ground wire to the copper heatsink wrap and cleaning the paint out of the inside of the tube.

I don't have pics but the switch was bypassed in the same way I bypass my mag switches so resistance associated with the switch internals don't compromise performance. The tail spring was bypassed with 22 gauge wire through the center.

I used this low resistance battery carrier and four eneloops to ensure enough current to thoroughly abuse the emitter.

I suppose it's done.

Tailcap measurements with four freshly charged eneloops spike at 8.4 amps and quickly settle in the upper 7 amp range. No signs of stress from the emitter have been observed. I'm unaware of any output tests of the old XM-L on copper so a lumen estimate would only be a guess. However, using Djozz' ceiling bounce numbers for XM-L2 T6 at 7 amps minus 5% for a glass lens and minus 7% average difference between XM-L U2 and XM-L2 T6 gives us around 1600 lumens. That number is perhaps grossly inaccurate and is most certainly based on several shaky assumptions. I just know it's bright. Beamshots in the snow suck but it's what I've got.

Happy modding,


Nice work as usual. I like what you do to those Defiant 51's. Nice budget mod for sure.

Personally, I really like the look and feel of them in hand . They make great gifts for non-flashaholics (Well, after modding if they take Eneloops).

Sweet. Looks like a real winner. Its amazing what one amasses over time.

“this abomination of a host” lol, this had me rolling :slight_smile:

Nice job of taking less than desirable components and making something usefull out of it.

Yep, looks like a winner, born from cast-off’s from the parts bin. :beer:

I must have a look through my parts pile one day……