Review: TrustFire TR-J20 - 12 x XM-L (3 x 32650) Chunky Monkey!

From the moment I saw the TR-J20 it caught my eye. The large chunky head, deep-finned aluminum heat sink, coupled with 3 x 32650 cells should do a good job as a flooder capable of sustaining high-mode run times. The size seemed on the cusp of what would otherwise be to large for a long term carry. As long as the reflector was properly designed, I thought it would probably be easy to improve the rest of the host if necessary (driver, thermal management, conductivity, etc.)

The TR-J20 arrived in great condition and looked as well finished as the stock photos above. Please excuse the dust on the light.

Pros:

  • Excellent thick robust aluminum construction and design
  • Water resistant
  • Excellent thermal management
  • Simple and easy to use UI
  • Excellent spill and satisfactory throw
  • Easy to disassemble and modify
  • Mode memory
  • Tail stands
  • Simple resistor modable for greater output
  • Robust non-galling threads
  • Near flawless anodizing and machine work

Cons

* Can not lock out by loosening the tail cap

* Slight blueish emitter tint

* Modes are H/M/L/Strobe/SOS - getting rid of the last 2 modes would be nice.

* Lens is not A/R coated

* No lanyard, charger, batteries, instructions or accessories included

* Plain brown box

Measured Specifications

  • Length 13 5/16”
  • Width 3 1/16”
  • Weight 3.26 lbs. (empty weight)
  • 12 x Cree XM-L
  • Aluminum reflector
  • 32650 to 26650 adapter tube included

Light was tested with 3 x Trustfire unprotected 32650 cells (not included).

Initial thoughts: this light was built as a medium-wide area flood light with moderate throw. Overall build quality and finish is as good as Ive seen in a “budget light”, which seems comparable to other top-of-the-line genuine TrustFire flashlights.

As can be seen in the above photo, the light easily breaks down into its sub-components.

The driver is retained by a threaded ring that is easily unscrewed with needle-nosed pliers.

Photo of the driver, which can easily be modified to provide additional current to the emitters for a brighter flashlight. I like a light that doesnt require advanced soldering skills to increase the output to blistering levels.
Mod Discussion thread

Photo of the driver mounting area. The aluminum is thick and well finned to conduct heat to the air.

And what we would all like to know… how well is the thermal path designed and does it have sufficient surface area to conduct the heat to the air?

The head pieces are deeply finned thick aluminum and have a large surface area.

The emitter mounting plate is machined from a solid aluminum round. YES!!! :bigsmile:

4 x 22 awg wires connect the driver to the emitters. The light is wired 2S6P to the emitters, which hints that the driver is a boost design which pushes approximately 18V to the emitters from the 3 cells (total 12.6V). The back side of the emitter mounting plate retains the reflector with 4 screws. Remove the screws and unscrew the bezel…

… and the reflector lifts out. Notice the thick aluminum floor plate where the screws passed through. Its approximately 1/4” thick! Ive just got to say that Im relieved and pleased to find the heat sinking portion of this light was well done. Where so many other budget lights have skimped on material to provide sufficient heat sinking and a good thermal path, this one does not. :bigsmile:

Emitter spacer rings are deep to clear the 22 awg wires, but might leave some room to to be sanded down to set the emitters deeper into the reflectors. MCPCB’s are 14mm.

Reflector surface is high luster and nearly flawless, with a few very small bumps that are nearly undetectable. The dust in the reflector photo was later removed with compressed air.

Performance:
High: 3.16A (Tail cap measurement)

In my opinion, the Fandyfire 9XT6 is a great light for comparative purposes. Its well driven from the factory and puts out a good amount of light without need for modifications (although a copper wire mod to the springs will give it a noticeable boost). But how well does it compare to the Chunky Monkey? :bigsmile:

Fandyfire 9XT6
High: 5.82A

Beam shots:

TrustfireTR-J20


Fandyfire9XT6

Range to the wall is just over 32 feet. To my eyes, both lights created a blinding wall of white light that I found impossible to tell any comparable differences. Setting the camera to manual mode to dim the image revealed that the harder driven Fandyfire appeared a bit brighter with a wider spill beam. It also had a nicer tint. But taking the two lights for a long walk revealed a few surprises. The Trustfire has more throw and it remains fairly cool in the 60 degree F night air during the 30 minute comparison. From a cold start, the Fandyfire had to be turned off after 8 minutes to prevent it from overheating. After it warmed up, it overheated much more quickly. Advantage —-> Trustfire.

Ceiling bounce test in lux

TR-J20
Initial - 147.7
30 sec - 147.6
180 sec - 147.4

9XT6
Initial - 179.2
30 sec - 163.2
180 sec - 137.9

On long high-mode runs, the Chunky Monkey just hangs in there and keeps on going without any appreciable thermal or voltage sag. The combination of Trustfire’s excellent 32650’s combined with an over built thermal path, great heat sinking and moderately driven emitters, produce a light built for sustained high mode use.

Final thoughts:
While this light is certainly at the top of its price range for a budget light, the build quality and attention to detail bodes well for the asking price. Possible future mods might include sanding or replacing the emitter spacer rings to seat the emitters deeper into the reflector and a driver resistor mod. The emitters are glued to the floor plate with fujik. The floor plate does not have reliefs fly-cut into it to index the MCPCB’s in their positions. This eases mod options for other emitter configurations. 6 x MT-G2? If both channels of the driver can run in parallel, then 6A to 3 MT-G2 emitters should be possible after a resistor mod. No guarantees, but there appears to be enough room to tri-bore the battery tube to accommodate 9 x 18650’s, but the threaded ends would be slightly castellated. Because of the thick treads, I dont think this would pose a problem to threading the head and tail cap, as long as care is taken to align the initial thread engagement before twisting it together.

If you have the money and use for a big flood light that can run in sustained high mode, this is definitley one worth strong consideration.

FlashPilot Approved :bigsmile:

Size comparisons:

Trustfire TR-J20, Fandyfire 9XT6, Trustfire X7, Fenix TK70, BTU Shocker

Its worth mentioning that I run 3 x 32650 Trustfire cells in the TK70 and get a sustained 6.22A tail cap reading. While this cell configuration is definitely not recommended for this flashlight, these cells dont even break a sweat in delivering sustained high voltage/high amperage at this level.

Many thanks for the review.

Are you able to put up a beam shot of the TR-J20 against something like an XM-L2 C8? I’ve never seen or used a light like the TR-J20 so don’t really have anything to gauge it against.

With the Amp ratings, you said 3.16A tail. Does this translate to 3.16 x 3 (for 3 cells in series) then divide by 12 (for each emitter) = 0.79a per LED?

Sorry but I dont have any other photo’s for comparisons. There are several threads on BLF that compare beam profiles. Here’s a great place to start.

Someone else might correct me if Im wrong. Since the light is wired 6S2P, I think it would be 3.16/2 = 1.58A minus losses in driver efficiency, etc. If losses were 20% (.316), it would be around 1.26A per emitter.

Sheesh! Im surprised its that bright on that small amount of current. :smiley:

That is a chunky monkey. Definitely needs a proper boost in current draw.

I’ve been looking to get one of these for a while just because of it’s sheer size, but something about it just seems off in the comparison shot. I think it’s the giant battery tube.

Chunky’s battery tube is definitely chunkier than the TK70 variety… so its aptly named. :smiley: Beyond what you get out of the box, it should provide a good platform for many interesting future mods. Im still thrilled with the thick 1 piece floor plate/sink and overall head design. There’s lots of room inside to radically change things around.

FYI

“Pros - tail stands
Cons - does not tail stand ”

What is this fuji white glue stuff you mentioned?

Thanks and edited. It tail stands.

Fujik is a cheap thermal glue used in many Chinese flashlights to secure the emitter star to the light.
http://www.dx.com/p/fujik-silicone-thermal-glue-50ml-grease-like-4579

That thing is huge...and calling my name...must resist...

I'm thinking: boost the stock driver until it burns out in short order (or if I get lucky and it doesn't!), then use it as a contact board, rewire the emitters to 3S4P, throw in an attiny+FET driver, and let 'er rip!

good lord - that makes the BTU look like a v10r LOL

How many amps per emitter would you guess with that setup? …and what are you trying to do? Cook hamburgers on it? :smiley: If I could find a replacement driver (in case I fried the original), Id like to try bridging the 2 parallel channels and driving 3 MT-G2’s (3S) after the resistor mod.

Edit: Ive also considered tri-boaring it for 9 x 18650’s and a different boost driver to power a 100W 97 CRI Bridgelux RS. Then I could BBQ ribs without a grill! :bigsmile: Id need around 26.7V at 3.75A from 12vin. Yeah, thats not going to happen without more voltage and going buck. All serial for 42.9vin. Hmmm…

Well, in my experience a good 18650 or 26650 will do around 15A into 3 XM-L2s, probably about 18 into 4 XM-L2s due to the voltage sag (32650 will probably be better here, and may see 20A+.) Since it is 3S4P and we have 3 26650s (or 32650s) on the input, I'll bet you see around 4-5A per emitter. Probably best to get some direct thermal path MCPCBs in there!

Jesus. Potentially the brightest budget modded light on the forum.

I'll bet with some copper MCPCBs and XM-L2s you can hit 15,000 OTF. I don't see any reason why you couldn't. Oh crap, forgot that this is a mechanical clicky. It may need to be converted to an e-switch to handle those kind of amps. That's doable.

On my J18, love hearing the "crack" sound of power when contacting the DMM lead to the battery tube for a tailcap measurement . Mine does close to 9,000 lumens, so 15,000 for 12 emitters isn't a stretch.

Yeah, they do that! The boost drivers do it much more though, I think there is a huge momentary draw as the inductor/capacitors get filled initially.

I couldn't resist. Finally ordered one...will be putting an FET driver in there and we'll see how it goes!

It’ll be a beast with a FET driver. I just might need to buy one from you. The best mark I can give this light is in its great heat sinking and sold thick floor plate. Makes a fantastic skull basher too! Please let me know how you like it.

Very nice review Flash. Thank you.

FlashPilot, what is the inner thread diameter of the battery tube? I have no love for Chinese batteries. However triboring for Sanyo 16650 would give a higher quality option with similar capacity. Really looks tight going the 18650 route. This light is really tempting; factory, FET driver or a slight resistor mod.