Extension tube for AA minimag

I am looking for an extension for a minimag so it will accomodate 3 AAs. Does anybody know if someone makes one of these? I posted over on the led board if any one could instruct me on how I can swap the lamp assembly out of a 3 AA MM so I could just use that body but got no response. I am wanting to put a xenon lamp in MM and try to overdrive it with 3 AAs. Any help would be greatly appreciated.

Tacstar sold these 1xAA extensions years ago. However, I don't think they've been available for many years. The other issue is the ID of the extension. I've found that some AA NiMH cells are too large in diameter to fit easily. Unfortunately, Eneloops are one of them.

If that's yours, Justin, very cool! :thumbsup:

I bought one of these Tacstar extensions approx. mid 90's. It was my first flashlight "mod". Unfortunately, I discovered a couple years ago that the alkaline in it had leaked, and wouldn't come out no matter what I did. It was a sad thing to have to toss it after 9 months of trying to save it (including 7 or 8 months soaking in vinegar to dissolve the dried alky gunk). :sigh:

Anyway, they came with their own bulb that was rated for the extra voltage because the stock MM bulb would blacken quickly, then blow soon after that. You can simulate this by running one on a 14500 Li-ion.

To answer Elseis66's questions, the positive end of the 3AA MM LED tube is designed differently than the incan, and doesn't look like your idea would work. Also, as mentioned above, the Minimag bulb doesn't respond well to overdrive. It's definitely brighter, but won't last long. You would need to find a T-1.5 size bulb at the right voltage. And, it would have to run cool enough to not melt the plastic switch/bulb holder, and reflector. More about this below.

The way to go is to use a donor Minimag tube for the extension piece, then find someone with a 5/8 X 28 die to cut the threads. A die is needed for this because the tube wall is too thin for machining. Here are a couple corroborating pics from my adventure down this path a few years ago. For further detail, check out post #12 of this thread.

Machining attempts... the one that didn't break was the wrong length, and probably wouldn't have survived screwing it onto the end of a MM anyway.


This is the die-cut extension. I treat the light this is on very gently, so I don't know how strong it is. Still hasn't broken though!


Now, back to your main problem here. You may not be able to find a useful bulb, and the ones you're likely to be interested in will melt the stock parts. This is why the Auroralite Minimag hotwire kit was created (the old thread is in the Marketplace... will link when the MP is back up), but they haven't been available for a long time, and rarely come up on Custom & Mod B/S/T. If you somehow manage to snag one, I'd suggest skipping all the hassle of trying to get an extension made, and run a Streamlight TL-3 bulb on two 14500 Li-ion. It'll be MUCH brighter than stock, and give a good 25 minutes runtime.

Member Litho123 used to sell a custom halogen filled Carley bulb (the H1499), but only has a few left, and won't be making more. Very bright, but with no availability, this is not the way to go. The Fivemega FM1794, now sold by Nite and Wonderlite is extremely bright, but 14500 Li-ion's cannot handle this kind of current draw. Rumor has it that AW is coming out with IMR 14500's, and this bulb would push even those batts to the edge... in addition to giving a ludicrously short runtime.

Again, if you can find an Auroralite kit, go with the TL-3 solution. Happy hunting!

Bimmerboy, I really enjoyed those cool, retro mods in your link.

Yes, that's my Tacstar extension.

elseis66, the way Tacstar avoided an overly thin wall at the threads is they use a small diam plastic spacer piece (with bottom copper contact and top spring contact) that interfaces between the top nipple of Batt #3 and the bottom plate of Batt #2. The contact piece diam is less than that of a AA cell, which allows the tube wall at the extension's thread to be of adequate thickness. The bottom copper contact looks like a copper rivet. The rivet's stem passes through the plastic spacer and the spring is attached to the top of the rivet stem.

The downsides are a longer extension and additional contact resistances.

See the following photo (the tail end of a stock AA Mini Mag is on the left, the spacer/contact for the Tacstar 1xAA extension is in the center, and the top end of the Tacstar extension is on the right):



I am using this extension to drive a Cree XR-E Q5 LED in direct drive. I use a mariposaoyako copper heat sink for the LED.

Thanks, Justin. Glad you enjoyed that. I've got more destined for that thread this coming fall.

Justin Case said:

Tacstar sold these 1xAA extensions years ago. However, I don't think they've been available for many years. The other issue is the ID of the extension. I've found that some AA NiMH cells are too large in diameter to fit easily. Unfortunately, Eneloops are one of them.

Click to expand...

Justin, you :rock: I knew I wasn't crazy thinking all these years I had seen (but never bought) those 1AA extensions!! (you don't happen to have a spare, do you?)

:rock:

Sorry. I wish I had several so that I could use some, and provide some. Bimmerboy's approach looks like the most workable option.

thanks for all the help guys, i'm just trying to figure out a way to make a decent incan torch without having to go to a CR123 host and I have eliminated any rechareable lithium set ups because I simply do not trust myself with them.

That would be pretty sweet running a 12V bulb with three of AW's IMR14500 cells.

elseis66 said:

thanks for all the help guys, i'm just trying to figure out a way to make a decent incan torch without having to go to a CR123 host and I have eliminated any rechareable lithium set ups because I simply do not trust myself with them.

Click to expand...

That's a very tall order! Let me save you a fair amount of time...

Without Li-ion's, and the Auroralite kit, you're gonna' have to go with the extra width of CR123's if you're looking for a semi-pocketable incan with decent output. For numerous reasons, my recommendation, although there are a couple other options...

Surefire 6P. Get a 9P if wearing cargo pants.

Edit: Perhaps an old school Underwater Kinetics 4AA might fit the bill? Still a great light, uses alkies, and can be found for about $20. Replacement bulb/reflector assemblies are about $7.

The only decent incans I've ever had that ran on alkalines are a dorcy that took 4 AA it was not pocketable at all and maglights that use 3 or 4 C/D batteries. I love my 6P and E2e both of which house a strion bulb and lithium ion battery.

That being said if you want a good incan with out going to lithium based lights then I would suggest checking out streamlights website. Specifically the propolymer that takes 4 AAs or maybe the twin task that uses 3 AA

Take a look at the streamlight scorpion as well, it's relatively inexpensive and has some pretty good output, small size as well.

They did sell a 3 AA version for a while; mine died from leaky alkalines.

I'd like to see a tube that will take LiOn diameter cells, with a slight step-down at the end to attach head. Would need to insert the "guts" of the light as well, so the front of the tube would have that inside diameter.