TrustFire TR-J12, $54-Shipped, Aliexpress

LED Flashlights – General Info 26650 Flashlights
8

During these thermal-runs and current tests the light started to get moisture condensation on the back side of the lens. At this point it was hot to the touch. So I dis-assembled it further...

Engine + dry threads and gasket. I ended up smearing a bunch of AS-5 on these threads to help aid heat transfer.

Heres the screws that attach the reflector and sandwich the LEDs.

Another view of the engine. Why do they scrape off the component ID numbers? The only other place I have seen this is high-end custom audio DIY, where the circuit designer wants to hide the ID of the components used to help deter other DIY builders from copying the circuit.

Nice tight fitting O-ring... This junction should be water-tight. Shown before the AS-5.

I let it run open like this for ~7-8 more minutes and get really hot, too hot to comfortably hold in my hand. Hopefully this allowed the trapped moisture to vent. One things for sure, this light generates a lot of heat... a good percentage of which needs to conduct through the entire heatsink area, and a small amount into the battery tube.

All dried out. I buttoned it back up, with arctic silver-5 on the threads. It has the consistency of white toothpaste, mixed with pine tree sap, and add some asphalt-tar for color... YUK!! Its a royal pain to clean up. It took 5 minutes to apply, ~45 minutes to try and mop up.

After all these HOT runs I checked Vbatt and the cells 'finally' dropped to Vnom=3.6V. I checked tailcap current at that point and measured 3.95-4A (fluctuated a little depending on how much pressure I pressed on the probes). It looks like the driver is pulling more current as Vin drops, as expected.

So in summary, the $54 J12 lights form aliexpress are legit... no clones, fakes from this seller. At this price its a really good deal if you are looking for a fat flood-beam from 26650 cells.

What I find most surprising is the performance of the 26650 cells. Even with a ~3.5-4A draw, they seem to spend a LOT of discharge time ABOVE V-nominal (3.6V). Unlike even the best 18650 cells, which drop from 4.2 => 3.6 much faster.

9

Hmmm something isn't right.

Why are my cells rattling like crazy inside? the light now flickers from intermittent battery contact.

whoa... what happened to the +B plunger? and whats that smell!!? (before and after pics)

Hmmm cells look like they sit farther down now: (before and after)

TOAST!! Poor little spring just can't hang. Melted and smashed. Time to go get some copper braid, and get current flowing properly.

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Noooo! Hope that doesn't happen with mine.

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Hold any more tests, annealed spring in my experience is normally a sure tell of a short somewhere. Those silvers you put could have dropped inside and doing the nasties.

Best bet if you would take a peek inside again.

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It very well could, especially if you are using low resistance 26650 cells. Its pumping a LOT of power+current through some very thin wire springs. It has a good heatsink design that can dissipate a lot of heat for long ON cycles. So clearly the springs are under-designed for this application. I didn't take pics of my tailcap spring but it too was rainbow + silver colored from heat. That pretty gold plating just gets smoked.

I'm off to frys to get some copper braid....

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Thanks for the great photos showing inside the light. Very unfortunate the spring got so hot. I'm debating whether to purchase this one from AliExpress or take a shot in the dark on the UniqueFire UF-S7. I'm going to decide by Monday morning on one of them.

Hope you can get your light fixed and all works out for you.

14

Just got back from Frys with some copper braid. Wrapped some through each spring. I'm not going to bother testing it, as I already am certain it will work and sufficient current will divert from the spring and through the copper wire. It kind of brought back memories of my Mag-incan days.

Ready to rumble!!

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I brought mine from Manafont but payed a lot more, now the difference is $17.80 usd more to yours, i did not have a moisture problem with long runs or the spring problem or discoloration.

My driver base is different to yours mine is flat with no nylon ring and just uses a spring direct to the battery. I am also pulling a lot more current then your's and still have not melted the spring, but i did break off the tip of the spring, but the torch runs fine still.

Ive never had any flickering or any bad smells or driver or tail cap plunger discoloration any moisture problems and Ive had mine a lot longer then yours....

I believe 1.97 to 3.4 amps should not cause these problems as Ive drawn more amps then that through similar springs with out discoloration of parts or melting any thing and 3.4 amps is only approx 0.4 to 0.6 amps more then the TR-3T6 on 2 x 18650's that ive run a hell of a lot.

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It funny because this light reminds me so much of the MAG-ROP (2x26650) that it replaces. I have had that light for ~3+ years, and use it every now and then. But those ROP lamps will vent some strange foul smelling vapor/liquid, so you have to burn the PR lamp in by running it for ~15-20 minutes straight with the window glass off. I also had to add copper braid wire to the tailcap spring on those ROP builds... just like this J12. It took a little effort but I think I got it dialed in now. I am a little bummed about my springs melting, I hope others don't have this problem too.

I hope mine lasts as long as yours benkie, its a great light so far. I was doing some ceiling bounce comparisons and LO mode is a really nice floody, cool running ~250 Lumens. Perfect for around the house tasks.

Yeah your driver setup looks completely different than mine. I found your old pics from a few months ago...

https://budgetlightforum.com/t/-/5619#comment-116214

Mine has a brass retainer that clamps the driver board in place.

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After all that water proofing let's see some underwater beam shots ..... he he

Nice light This is my next light ........

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Yep thats our old kitchen table.

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You need to get some of these heavy duty springs for the tail cap. I have a couple extra if you want I can send you one.

http://www.cnqualitygoods.com/goods.php?id=1442

They are very difficult to solder because they are coil is so thick, you need to get them really hot for the solder to stick. Don't mind the lame braid attempt I was just demonstrating the technique for another thread.

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Thanks for the offer Eric... I think I am good though with the copper braid. I just wove it around the spring coils and stuffed a wad of it inside the spring.

Switch spring:

I also played around with some old exhausted sanyo 18650 cells that were ready for the recycle bin. These tired cells measured ~1000Ah capacity. I ran them down to ~3V, where the tailcap current draw peaked at ~6.8A, and then rapidly dropped from there. So I think this sample J12 falls a little short of the 7.5A claim, but its better for the well-being of the cell at that point in its discharge.

21

The claim is 7.5A current output across the LEDs.

So with 8.4v x 3.4A in, and assuming 3.2A vf and 85% driver efficiency, that comes out at around 7.8A output. Just above the rated amount.

I wouldn't worry about it.

22

hey guys,

I was doing a runtime test on my one with 3 partly charged Panasonic NCR18650A 3100mAh protected batteries.

It went for 1hr then all of the sudden the flashlight turned itself off (there wasn't any noticeable dim during the hour btw).

I thought the J12 meant to change to lower modes first before shutting down completely? Is this correct?

When I checked the batteries, they were around 3.05V left in them.

I thought these batteries can go down to 2.5V before the protection kicks in and also thought the J12 can run well below 3V as well.

Hmmm, what is going on...

23

This is not related to your particular case with the J12, but:

Just keep in minds that voltage on load is always lower and it's current dependent. A large current will cause a bigger drop on load vs off load measurement. But then your NCR18650A might simply have a 2.75V cut-off not 2.5V. What brand are they?

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These ones:

http://www.intl-outdoor.com/panasonic-ncr18650a-3100mah-protected-batteryone-p-333.html

Damn. Kinda confused on off vs on load voltage..

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Those can for sure go down to 2.5V, maybe even 2.4V

Off vs On load:

I am not familiar with how the J12 when it cuts and so, but as a rule what a driver sees is the voltage on load, the higher the current the stronger it affects the voltage. Once you take the cells out and measure the voltage, the battery is off load, thus the voltage is higher than when it is powering something.

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Shopbot, the protection on the batteries has not cut any power, if that would be so then you could not have measure any voltage but 0.0V.

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After reading this I took some depleted Sony 18650 cells and ran two them down in my J12. These cells were depleted previously down to 3V in a capacity test, and deemed too little capacity to be any use. But they're suitable for tests like this when I want to see how a light behaves when the cells run down. The cells had rebounded back to 3.8V.

I ran the light tailstanding for a few minutes, enough to get the head very warm. Took a tailcap current measurement and the boost circuit was pulling 5.5A. I noticed the cells were VERY hot at this time. Too hot to comfortably hold in my hands, so I stopped the test here (fearing some kind of melt-down) measured the cells and they rebounded back to 3.5V each.

Paused here and let everything cool down for 20 minutes.

Ran the test again. Cells started out at 3.5V each. Re-loaded them and ran them in HI for 4-5 minutes (as I type this), long enough to get the light warmed up again. Measured current draw, and it was still pulling 5A, down a little ~.5A from before. The cells were once again very HOT, measured cell voltage and it had dropped to 3.3V. So things seem to slowly be dropping, as the cells deplete.

Paused here and let everything cool down again.

Ran the test again. Cells started at 3.35V. Only this time (knowing the cells will be completely depleted) I ran the test without the tailcap, passing current straight through my Fluke meter. Current topped of at 7.2A for a brief moment (maybe 10 seconds) and started to drop rapidly down to ~1.75-2A. Went over to the wall and confirmed HI output had dropped to MED, so the circuit was doing what its supposed to. Truncating the HI mode. The other thing I noticed was mode switching began to "flicker" a little between modes as I flipped. It wasn't a crisp HI-MED-LO cut. Pulled the cells and they measured 2.85V each, and they rebounded back to 3.25V after a 3-4 minute rest.

I Re-loaded the cells and ran the light again. At this point its clear the circuit is dropping both HI and MED output down to a lower mode, maybe a little brighter than LO. At no point did the light output cut off completely. I stopped testing here, bad/dangerous/explosive things can happen running Lithium cells depleted this far.

BLF'er benkie and a couple others have been very vocal about the existence of fake Trustfire TRJ-12 and J18 lights... and from reading others comments and reports that appears to be a very likely scenario. Personally I think it goes deeper than that... I think it has to do with the driver board supplier, and their ability (or lack thee-of) to manufacture the same DC-DC circuit form batch to batch. I have always wondered why they take the extra time to scratch off the component ID and BIN numbers from the SMT components. After reading threads like this HERE , I personally believe the driver board manufacturers are stuffing the circuit boards with whatever components they can get their hands on. They may not always be 100% compatible or identically capable. By the time you add together the cumulative sum of inter-mixed parts on each board, you end up with the variation we are seeing across the population.

Anyhow... I think this particular J12 from the aliexpress $54 batch is a good one. Just be careful with unprotected cells, and don't run them all the way down. Watch out for HOT cells, HI mode dimming down to MED, and a slight "flicker" between modes, these are all signs the cells are fully depleted.