Maglite Mini-AA Incan to LED Mod Rehash

pc_light

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On another thread member Number21 asked about drop-ins for old 2-AA Maglites, I mentioned a mod I'd done using an AA and member LiftdT4R was interest in details, so rather than to hijack the original (any more than I already did) I created this thread so that I could provide details here.

Yes, I know there are better lights out there for the money.
Yes, there are easier ways to upgrade a minimag AA.
And finally, why bother? - because we can, it was fun and I'm a flashohic :)

I didn't intend to create detailed step-by-step instructions so I didn't take photos of the progress as I was working. Frankly I just followed along the recommendations of some earlier threads, that did a better detailed explanation. FWIW, here is my take on the steps, nothing new or novel, just sharing what I recall.

(Apologies original author for not including reference to their thread, I can't seem to Search/find it anymore.)


Here are the list of materials -

  • AA Minimag Incan Host (I started with an old Minimag but they can be found at close-out from Walmarts for like $5-7 these days)
  • $2 AA 800mA Linear Boost Driver from FastTech
  • $1 20mm Acrylic Optic from FT
  • $5 XP-L V5 4500K from FT
  • $2 Brass P60 Pill from FT
  • $3 21mmx1mm Glass from eBay
=========​
$13 Total +host​

One more item I purchased was a large 1/2 shank drill bit to make light work of the required boring (<$10). The other/previous mod threads recommended using a 25/32" drill bit but I opted for something smaller (23/32") so that my fit could be more snug. The size is variable depending on how much one intends to file/reduce the brass pill. Even the drill bit is argeably optional, since one could dremel or sand the inside to achieve similar results.

Step 1 -
Completely dissassemble the guts of the MiniMag AA. The switch where the bulb is inserted can be disassembled by prying off the bi-pin holder and simply punch the remaining portion down into the battery tube. When done we have an empty bezel head, and battery tube.

Step 2 -
Prepare/resize the brass "pill" (second from the left). I filed & sanded until all threads were gone and walls smooth/straight and overall round. In my case, I re-sized the diameter down to the previously mentioned 23/32".

(Empty P60 Assembly)
gTgkKD0.jpg


Step 3-Dry fit or rough assemble the brass pill, LED driver and LED/mcpcb. Mount the TIR optic and take a measurement of the overall height of this light engine assembly (from bottom edge of brass pill to top surface of optic).

Temporarily replace the old/original plastic reflector into the head and make a note of the height/distance or how much it sticks up from the top of the reflector to the top edge of the head (e.g., 1.4 mm). Whatever that measurement is subtract this number from the combined height of the assembled light engine. This measurement is the bore depth for the next step.

In other words, when the final light engine assembly is inserted into the finished bored bezel head, it should stick up by this same amount so that the glass and retaining ring fit as original.

Step 4
-
Prepare/resize the Minimag bezel opening (from the Glass end, with glass and ring removed) to 23/32" diameter (or matching the brass pill diameter). This can be done fast using a the drill bit or with a some time/effort using a dremel/sanding/etc.
NOTE: Remember not to bore all the way through. Leaving a slight lip/ledge will provide the pill a place to rest when inserted into the head. The exact depth of the bore varies depending on the height determined in the previous step.


QaAHxE2.jpg


Step 5
-
Assemble LED light engine (driver+ small spring (item on far right of P60 assembly picture at top)+pill+LED on MCPCB+TIP Optic). Place into bezel/head and replace glass/retaining ring. The head is now complete. There is one more step, to prepare the battery body.

DdOJ2NL.jpg


Step 6 -
Since the minimag does not use a tailswitch (or even if it uses an after market clicky) the next and final step is required to enable the battery to make contact with the driver. One must sand the end of the battery tube so that bare metal is exposed. This exposed metal is needed to make contact with the outer ring (negative/cathode) of the driver to turn On/Off.
NOTE: Be careful NOT to sand/expose metal on the thread sides of the battery tube and/or to the extent possible avoid exposing metal on the threads of the head. Doing so will result in a closed circuit which means the light will not be able to be turn off. Similar to all twisty lights, anodizing is required on the thread surfaces to electrically insulate and keep the circuit from unintentionally closing.


Here is the business end of the completed light and resulting beam (my rough estimate, about 250 lumens). In my case I chose a medium throw optic, one can optionally choose a narrow, wide or even mule (i.e., no optic) depending on the desired results.

If you do this mod. please remember to share your results :twothumbs

VE3U8r8.jpg

HEGip2u.jpg
 
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LiftdT4R

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Awesome, I'm def gonna put this on my mod list. What kind of battery are ya using and what kind of light/run time are ya getting?
 

pc_light

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It's just a fun light I keep around so Lithium works best since it sits unused for long periods. I've never done a continuous runtime plot but my 14500 with dummy cell draws 0.9-1A on max.

If I were to use this heavily, I would definitely use 2xNiMH, which I measured at 1.4-1.5A on max.
 

Bimmerboy

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Very cool, and nice beam. Love Mini-mag mods!

Many aren't "practical" cost-wise, and often don't have the greatest thermal path, but no matter. Mini-mag mods will always be cool. Heck, we had it a lot worse back in '04 with less efficient LED's making all that heat per Watt, lumen droop, and terrible stars compared to today.

BTW... the reason for the higher draw on 2xNiMH is that Vbatt is further away from the LED's Vf than 1xli-ion, so the driver has to pull harder from the batts to try to meet the spec'd current. There is more efficiency loss and heat in the driver this way, and most likely lower output. But, the Nimh's should give a longer runtime anyway with this setup, and a cooler LED due to slightly less current.

Kinda' surprised at the 1A draw on the li-ion, but I don't know the typical Vf range of a XP-L HI. Perhaps it's going direct drive with the li-ion, and battery sag is keeping things from running away? Could be making a lot more than 250 lumens for a short time.
 

WalkIntoTheLight

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Inspired by this post, but too lazy to do a proper job, I repurposed an old 2xAA incan minimag to use a 5mm LED. I used an amber 5mm LED (forward voltage around 2.2v), soldered on a 22 ohm resistor (to cut the current down to 20mA or less), and then poked the ends into the bulb sockets.

I can use it in "candle mode", and it actually makes for a nice candle. Very warm light, and it runs for 1-2 weeks on rechargeable batteries. I never tested how long it will run until dead, because eventually it gets too dim to be useful. But it's decently bright for about a week.
 

Icarus

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:thumbsup: because I like ALL Maglite mods! And as some people here might remember I did (and still do) many. All sizes AA, C & D. :)
Believe it or not but one of my most used EDC lights is this black modded MiniMag. :whistle:
 
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pc_light

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:thumbsup: because I like ALL Maglite mods! And as some people here might remember I did (and still do) many. All sizes AA, C & D. :)
Believe it or not but one of my most used EDC lights is this black modded MiniMag. :whistle:
Icarus, your work is in another league from us mortals :bow:

I think my favorite is the "Customized FM-14670 MiniMag".

Do you make some of your mod part available for reasonable? A good clicky tailcap would be nice.
 

Icarus

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Icarus, your work is in another league from us mortals :bow:

I think my favorite is the "Customized FM-14670 MiniMag".

Do you make some of your mod part available for reasonable? A good clicky tailcap would be nice.

By far the best switch for the AA Maglite I ever could find is the Terralux TCS-1. Back in time they were reasonable priced and I bought a bunch. I used them in mods up to 1.2A measured at the tail. I'm using a couple MiniMags equiped with this switch nearly daily and so far not one ever failed. I did a search to see if they are still available and it seems they are. I'm not sure if it's allowed to post a link here but I can let you know by pm if you want.
 

pc_light

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Found another old Mini-Mag incan and decided that before I upgrade it with the above drop-in mod that I would give WalkIntoTheLight's 5mm mod a try.

Afterwards, I liked the mod enough that I might not go the next step and simply leave it as-is for a long run-time low-level utility light.

LED used - 5mm LED Yugi 3200K hi-CRI, the leads were sanded thinner and squeezed to same gap as OEM bulb
Reflector mods - Base opening was widened to accommodate 5mm LED, surface was rippled with clear spray for orange peel effect.
(I had to add a small ring shaped spacer to the bottom of the reflector to restore height so that twisty action would again turn light On/Off. I could have avoided this by drilling the hole wider rather than sanding the bottom off :-(
Current Draw on Fresh cells - OEM Bulb ~400 mA vs 5mm LED ~50mA (direct drive, hence the LED is slightly overdriven without a resistor)

Here are the results -
(camera exposure settings were the same for both setups so that relative brightness is accurate; WB was set to 5000K)

Original Maglite Bulb (and reflector) on the left - 5mm LED (and modded reflector) on the right -
jL18U5j.jpg



At the tightest setting for each (the OEM bulb is drawing 8X the current) -
4JELaih.jpg



At the widest setting for each -
r5Y7UYQ.jpg



On Candle mode -
ZGZEFkZ.jpg


A while back I purchased a set of Tenavolt 1.5V AA Rechargeable Lithium Batteries. These batteries deliver a flat 1.5V x 2 =3V, so I decided to use them in this light for flat constant current output without any battery sag.

I don't have a light meter but the OEM bulb with fresh cells at 400mA draw is clearly many times brighter than the 5mnm LED which draw only 50mA. The OEM bulb has the throw advantage for distances greater than ~20ft but for lesser distances and/or close-up on the widest reflector setting, I prefer the even illumination of the 5mm LED setup.

-------------------
Edit - added spacer for twisty On/Off
 
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devryd

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Hi @pc-light
I just found your mod and I am planning on doing it myself. Is there anything you would change on the build from 2018, or can I reuse the parts you picked?
I know it is a long time ago, but i don't know if anything new came out, that would be better fitted for this build.
 

pc_light

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Welcome to CPF Devryd.

It just so happens that I made another mod for the Mini-mag mentioned above and FWIW I used the same basic approach above with only a couple of tweaks.

(1) This time, I didn't sand down the entire battery tube front end as I did previously. I only sanded off enough of the anodizing from the front of the battery tube to expose bare metal for electrical contact. The OEM hole is large enough for the drop-in center spring to clear the side of the opening without shorting against the edges. I did this so that I could easily restore the light to using the OEM bi-pin bulb or the 5mm hack/mod (above) if desired. This approach of leaving the OEM hole intact is optional but if you do entirely sand off the front end, the head will sit further down past the o-ring on the battery tube which is a good thing.

(2) I added a clicky tailcap because the twisting On/Off was a little touchy and sometimes it would miss levels when I tried to change modes, at least with the driver I was using. With the clicky tailcap mode changes were definitely more spot on. Do the mod without first and if you decide a clicky would help you can usually find a Nite-ize one for less than ~$10 somewhere. Again, this is optional depending on how your driver behaves. If it's a 1 or 2 mode driver, it shouldn't be necessary.

Last but not least was I tried a different 17mm driver and LED combination but that's the beauty of this set-up, you're at liberty to use whatever driver & LED you prefer.

The clear TIR is great for traditional beam but I also have a pebbled surface optic which smoothed out the beam for close-up flood and it's looks great.

Go Slow and enjoy the process. Goodness knows there are cheaper/easier ways to buy/get a better light but then what's the fun in that.
 

devryd

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Thanks for the answer. What LED and driver did you use this time? I was looking around a little for more efficient LEDs but i didnt find a lot. Are you still running the driver at 800mA?
Can the maglite handle the heat? Or does it get too hot? I am really new to flashlight modding so please forgive me if I ask stupid questions. I thought of using the moded mini mag as a bike light. Will it be bright enough, or should i use something different for that.

Also you used the word TIR. What does it mean?
Thanks for your help
devryd
 

pc_light

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This time around I used a similar 1-2xAA driver but with only L-M-H modes and no blinkies. For the emitter a SST-20 4000 Hi-CRI emitter. The first one was made of spare parts but for this one I decided to make one I'd more likely carry.

Good question about heat. there's good contact between the brass pill and the Maglite head so it seems to handle the max 800 mA fine. On High it will get warm after a while but not uncomfortably so.

I use 18650 lights for riding but depending on how dark it is where you ride, how fast you ride and whether there are unusual hazards, it might work. It probably puts 200-300 lumens out the front in a 45-deg or so beam.

TIR's ("Total Internal Reflectance") are optical replacements for reflectors. TIR's capture the scattered/spill light like a reflector and further manipulates it using the optic portion to create a reflector alternative. The advantage is that TIRs typically take up less room than a traditional parabolic reflector and they can to a limited extent be trimmed and shaped. Most TIRs will give a wide even hotspot will little to no spill, compared to a traditional reflector beam profile which is a tighter hotspot with accompanying wider spill. Search for TIR Optics and there will be loads of threads discussing their Pro's and Con's.

Good luck with your mod.
 

devryd

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jfezvkfd_jpg.htm
Today I started my own Mini Mag mod. I tore down the old one and installed a copper pipe as a spacer in the back since I will be using 1 14650 battery as power source.
I am still waiting on the stuff from fasttech, so I dont know when I can go on with the mod

jfezvkfd_jpg.htm
https://www.directupload.net/file/d/5741/jfezvkfd_jpg.htm
 
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pc_light

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If you like 14500, you can also consider picking up some AA-dummy cells. I keep a couple around for situations where I substitute a single 14500 for 2-3xAA applications. A lot lighter weight than copper pipe.
 

devryd

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The copper pipe has a wall thickness of 1mm so it is not heavy. I wanted the 14650 because they have a little more runtime.
 

Buck91

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Inspired by this post, but too lazy to do a proper job, I repurposed an old 2xAA incan minimag to use a 5mm LED. I used an amber 5mm LED (forward voltage around 2.2v), soldered on a 22 ohm resistor (to cut the current down to 20mA or less), and then poked the ends into the bulb sockets.

I can use it in "candle mode", and it actually makes for a nice candle. Very warm light, and it runs for 1-2 weeks on rechargeable batteries. I never tested how long it will run until dead, because eventually it gets too dim to be useful. But it's decently bright for about a week.

I did a runtime test a couple years ago with a nichia gs in a minimag running direct drive off 2aa. I don't remember if I used alkaline or nimh. But I had multiple weeks of usable output. Maybe search for that post if you are curious...
 

devryd

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The stuff I ordered arrived a few days ago and yesterday, I managed to put it all together. It works and it is really bright. It is definitely not as clean as I would like it too be, but I am happy. Somehow the driver doesn't seem to work properly though. I measured 2 A at the tailcap with a single 14650 cell. I mean, I dont know the efficiency of the driver, but i doubt. that it is below 40%.
 

pc_light

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...I measured 2 A at the tailcap with a single 14650 cell...
Congrats on getting it done. That does sounds high, as mentioned previously my light with 1x14500 and a dummy cell draws about 0.9-1A.

I'd double check various connections to minimize as much resistance as possible. Try cleaning all contact/connections and perhaps different dummies to see if the amperage draw can be lowered.
 
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