SMJLED Chinese Clone AAA

I bought some of these in the GB and modded them with SMJLEDs. Here's a step-by-step:

1) Remove the PCB/LED unit.One of my lights luckily missed the crimping operation, and the PCB fell out with finger pressure. The others were crimped and required straightening with pliers and much more persuasion (read whacks) to extract the PCB. The metal is quite thin at the end of the head threads, and it is likely the straightening will shear off a portion of the first threads. Remove and continue leaving as much as possible. Don't try to clean up the end by removing more threads or the PCB might not stay put later.

Once you get it as straight as you can, you'll need to force it out. I removed the nose of a pen, placed it on a hard surface with the nose up, set the LED of the assembled light (without battery) on the tip of the pen nose, and gave the end of the light a few whacks with screwdriver handle. You will win.

The legs of the LED have probably buckled, the base of the LED hit the top of the inductor coil, and the plastic housing of the coil has probably lost a few bits. No problem, it should still work.

2) Remove the stock LED. Save the tiny O-ring on the LED, heat the LED leg connections as you pull the LED off. This part doubles as a test of pain threshold or insensitivity to heat. Once the LED is off, heat the PCB holes and suck out the remaining solder with a solder removal tool.

3) Prep and mount SMJLED. Bend the legs of the SMJLED into a yoke with the proper spacing for the PCB holes (1/4") and so the legs are parallel. Insert the SMJLED into the holes observing correct polarity. The longer leg of the SMJLED is (+), and the PCB is marked on the underside. Install the tiny O-ring on the SMJ and butt it against the LED shoulder. Your objective when soldering the legs to the PCB is to have a gap of 0.220" between the top of the O-ring, and the top of the PCB. This is the dimension of the head from the PCB shoulder, down to the backside of the reflector. This is somewhat important as it will affect the focus if you're off. I determined this by lighting a loose SMJ by squeezing a coin cell between the legs, and playing around with the position and beam in an empty head. I found that installing the tiny O-ring on the SMJLED, and butting it against the back of the reflector, I duplicated the best beam. To get the proper SMJLED position when soldering, it helps to gently squeeze the untrimmed legs, sandwiching the PBC. Again a test of heat resistant fingertips. Simply reheat and nudge if you get it wrong. Only when you are satisfied, trim the legs of the SMJ.

Note: I measured the voltage across the legs of the stock LED running on a Rayovac Max alkaline, and I got 3.6 V. I didn't measure current though.

4) Reinsert PCB/LED into head. This is pretty self-explanatory, but be sure to press on the very edge of the PCB, not on the components or center. Be sure the tiny O-ring is on the SMJ beforehand.

5) Crimp. I didn't do this, but it may be advisable to ensure a better contact between the PCB and the head.

6) Enjoy.

Here are some pics:
A stock head, PCB/LED removed, SMJLED mounted & removed LED, finished unit



Stock head and PCB unit, SMJLED head and soldered, untrimmed unit



Beamshot: SMJLED Clone, Stock Clone, Arc AAA-P. All on fresh Energizer Li primaries, 10" from white wall, F4 & 1/4 sec.



Personally I think the SMJLED clone has a great beam. Great spill, decent hotspot, minimal artifacts, and uniform tint. Not quite the throw of the Arc, but overall preferable IMO.

Lineup of some SMJLED modded lights: My "lipstick" light, Lambda's TurboMate, Chinese clone wrapped in shrink tube.



I also did a post on what I call the "Chinese Clone Lottery"- findings of the various manufacturning QC issues and suggested remedies here:

https://www.candlepowerforums.com/posts/1245243#post1245243

Amazing, thank you for the pics. I totaly destroyed one of them so far and it wont light up now, Oh well:mecry:. What a great little light we have here.

Hey pretty cool. I think I need to get some SMJLED's.

Just wondering if an uncut SMJLED might give more throw since there isn't much reflector?

Excellent write up Zep! I am wondering though, since the SMJled is about 6 x the price of the nichia CS, is the price difference worth it? Also, while looking for LEDs I came across 10 mm 4 chip LEDs (and I believe some 8mm 4 chip leds -might be mistaken on that though) but no 4 chip 5mm LEDs, is it possible that the SMJled is actually a 10mm cut down to 5 mm size?

I'm also curious about how appropriate the circuit boards from these clones would be for modding solitaires. With it now possible to HA3 a solitaire, a HA3/smjled solitaire might be quite a kickin pocket light.

Mr. Light, I don't think uncut smjleds are available, that is one reason I'm wondering if they start life as 10mm leds.

Xochi,

I think you're correct about the uncut SMJLED's not being available, but Lambda would be the one to ask.

Though I haven't tried the Clone circuit in a Solitaire, I think it would work very well depending on what emitter you're driving.

I don't pretend to be an expert on converters and would appreciate anyone chiming in to correct or add to any of my information, but I believe the circuit in the clones is a simple boost. What goes in comes out a certain percent higher. If you are using a particular boost circuit, and have a certain emitter you are trying to use, you could vary the power to the emitter by adjusting the voltage supplied.

I know the stock circuit on a 1.5 V cell will light a Lux, I've done it on a bench. I think it was underdriven, so if I wanted to increase the output, I could have tried a 3 V cell, or a Li-ion. This will work up to the point you fry the circuit (or the emitter). If you do, consider it cheap tuition. Luxes generate more heat, so heatsinking is another consideration.

In bigger lights, there are other cheap boost circuits you can use. The Xnova 5 LED light has a robust circuit that works well in miniMags and the larger lights. Emilion and Dae carry these in the dealer's forum.

As far as the value of the SMJ compared to a Nichia, that's up to you. The beams are quite different; the Nichia has sort of a built-in lens that alone creates a hotspot, and the SMJ emits a spread of light that needs a reflector, even a tiny one, to give it focus. The SMJ has much more spill, and more uniform tint with no rings. Both deliver a comparable output, but considering the spill I think the SMJ emits more light at the same current. I like spill and a flood beam for my typical uses for a keychain or pocket light. If I want throw I use something bigger, and typically with overkill. If you are looking for the most bang for the buck, it's hard to argue with the Nichia. Either way, I guarantee you'll be happy with it since it is your own blood, sweat, and blisters.

I don't know the maufacturing origin of the SMJLED's, again Lambda would be the authority. But I would guess that it would be much easier to make a whole new die than cut down all those 10 mm emitters to create the SMJ. If you order some SMJ's you could probably deduce this with very careful inspection of the guts of the emitter. From what I can tell by the housing of the SMJ, it looks to have been molded into it's form, not cut, and the tip polished.

LED
have you figured out the current yet?

obviously the 3.6v is ideal - and would love to know how hard a Nichia CS or Snow 29 LED would be driven in these things...

Looks like a cool little mod.

I'm still unsure about the origin of the MJLED/SMJLED... I swear they look very similar to the LEDs in the Nuwai .5W lights and the River Rock 2xAAA lights but the Lambda LEDs are consistantly less blue than the Nuwais.

As to current for the Nichia CS and Snow29s, I've run both direct on a LiON cell so 4.2V down to 3.7V and initially, they pull about 170ma then drop down to about 120ma by the time the cell itself is down to 3.7V. These numbers are with a Nichia CS B0 on a 10440 cell. I've also run a Nichia CS C0 on a 14500 cell and have gone through about 6 or 7 charge cycles three of which were non-stop. One of the Snows I got from you has seen duty in an identical setup on a 14500 but I've only charged the cell twice and is currently on the third charge. I haven't done a side by side comparison to see if the Snow has dimmed after being driven this hard, but the Nichia CS C0 is still just as bright as when new.

Still, I'd like to be able to run the MJLED or SMJLED on a rechargeable cell so I might try something like this. I'll probably get one of the uncut ones and try in an Inova X1 eventually but right now I'm too busy installing and playing with colored LEDs in the X1.

lebox97 said:

LED
have you figured out the current yet?

Click to expand...

I measured the current through the stock LED and through a Nichia (I don't have any more loose SMJLEDs) by unsoldering one leg of the LED, hooking up the PCB to the cell with clips, and probing between the leg and the PCB. I measured about 50 mA each running off a Rayovac Max alkaline @ 1.58 V.

Next I took a stock head and hooked it up to the cell, and used the probe to complete the circuit between the (-) battery end and the head housing. I got a measurement of aprox. 200 mA. The same measurement with the SMJLED head yielded 150 mA.

I'm not quite sure what is going on here, or if I did anything wrong, but those are my results.

I took the opportunity to measure the voltage of the powered PCB without an emitter. I got 5.03 V between the LED contact holes of the PCB with no load on the same Rayovac cell.

I don't think you did anything wrong... if a light uses anything more complicated than a simple resistor, then the current it pulls from a cell will be more than the current it sends to the LED.

I bought ten of these lights and so far I've tried them with a cut down smjled, a 1 watt luxeon (don't know bin code), a U-CO binned Nichia Cs ,a cut down Nichia CS and a lux III (TV1J).

One thing I can say is that for what these lights are, they actually have an excellent reflector. These have actual metalized parabolic reflectors that do a good job of focusing and I got very pleasing beams from the uncut smj led and even after cutting and polishing a nichia cs, I got the beam that is typical of a reflector , that being a central hotspot surrounded by a corona of sidespill. Getting the cut nichia into the sweet spot was a royal PITA since the die is so high in the acrylic there is just barely space to mount it in the right place. The nichia with it's standard optic does well in this reflector as well. My favorite so far in this light is the U-CO nichia, the smjled is a bit brighter but I love the very warm tint of the nichia. The smj is very cool and seems to wash out color. I think I may be real sensitive to the bluer leds or something.

Although these lights are very cheap and the quality is pretty in line with the price I'm having alot of fun modifying these and I've come to the conclusion that , IMHO, the Arc AAA would be signifigantly improved if it adopted a parabolic reflector of greater reflectivity.

Thanks again Zep for a great right up . These mods are 5 stars of flashlight goodness in the fun and cheap categories.

i just did this mod with a 29snow led. I had to grind down the acrylic with my dremel and hand polished it to near clarity. I didnt re-crimp anything as it seems to work without it. All I have to say is amazing.. it made this light much more usefull. This is my favorite light by far. It's nearly as bright and just as pretty as my 1/2 watt 1xaa light from advancemart.

edited to add my sorry beamshot!


This is my modded one on the left.. and the original (still decked out with a clip and rubber grip on the right. The spill is much cleaner larger and brighter on now. The hot spot is not as large but somehow It feels like it throws better now that it's using its reflector.

I just got one of these lights and I'm thinking of putting a 380nm led in there.
Mine looks potted. At least the back is black... Looks like it's oozed over the outside of the head a little too. Will there be any issue getting it out of the head?

getting them out of the head is by far the most dangerous in terms of damaging the pcb. The inductor? the coil of copper wires is the most fragile. I had to superglue over my coils on each of mine to keep the wires from unraveling. One drop of glue and let her sit.. then continue working after it's dry. I used a 9mm bullet and a hammer to get mine out.. neat hu? I stayed away from the primer. Anyway, the FMJ head of the bullet was perfect in that it wont scratch the lens and was deep enough to push the led all the way through. Dont hit it hard.. just firm smacks, and hit the battery tube / body, not the head itself. That wouldnt make sense. The back of the led will hit the inductor coil and break the plastic off the top, then the pcb will be forced out the bottom of the head. Works like a charm except the one where i broke off the tiny little resistor and now it doesnt work. Micro soldering failed! This will be my direct drive host the day i get some Lithium rechargable AAA batteries and a charger... Maybe i'll power my K-2 emitter in there..

Anyway sorry to ramble.. soldering is fun.. im about to do some now.

But did yours have any black potting material over the back side? I'm thinking I'll have to heat it before it will come out... Hitting a bullet with a hamemr is too dangerous for me!

well, i didnt hit the bullet with a hammer, rather I stood the bullet on the counter and hammered the light led down into the bullet.. nothing impacted the primer and the whacks were not enough to set the bullet deeper into the casing.. no no harm no foul. As far as black potting material.. i havn't seen any.. but feel free to heat the head up, the pcb seems to be rather imperveious to heat. I'd set it down and heat up the head and hope the crud runs out.. ?? I take it the head isn't crimped?

It's crimped and it looks like black potting epoxy over the back. only thing left exposed is the solder blob. Perhaps it's just paint covering the back side components? I'll find out when my 380nm UV leds come in I guess...

If you can, take some pictures.. we'd love to see the black goo that you speak of... and before / after shots are nice too.

I haven't seen any heads that are potted, but if it's anything like the Arc AAA head, the stuff is a royal PITA.

My first attempt at unpotting and Arc head was heating with a microtorch. It did loosen the PCB up, but I made the mistake or trying to pry it off and break the LED leads. It came off all right, but the top half of the inductor coil stayed in the potting compound of the head.

I ended up baking it in a toaster oven @ 400 degrees for 10 minutes, and that softened up the potting and made it release. It became soft and brittle and chipped off easily.

Having ruined the Arc circuit, I used the Clone circuit in the Arc AAA head with a TWOH Lux. It was a nice beam, but not bright. A stock Arc AAA-P had a brighter hotspot.

Then I cleaned all the components and potting off the Arc PCB, and simply used it as a contact board for an SX1K Lux, direct drive off a Li-ion in an Arc AAA head and N-cell (or Arc/Peak) body. WOW! It has amazing output, but gets rather warm. It does stabilize to a nice hand warming temp, and hand cooling keeps it comfortably warm and not too hot. A pocket rocket indeed.

Where did you get your Lithium Ion AAA and charger? I'm trying to find the best option for this light to direct drive the new k2 emitter. will it be too much for this light or can i / will i be underdriving it? I also want to be able to use rechargable 123 and AA size batteries for other crazy mods im doing. All at 3.6 volt is fine. Protected is a bonus.