Acebeam TK16 (Luminus) Flashlight Review

Acebeam TK16 (Luminus) Flashlight Review

The Acebeam TK16 flashlight is available with emitter options – here’s the Luminus edition. This is a nice e-switch triple flashlight!

Official Specs and Features

Here’s a referral link to the Acebeam TK16 (Luminus) Flashlight product page.


There are a number of versions.  First the emitters.  There’s a Luminus SST20 High CRI edition (seen in this review).  There’s an Osram edition.  And there’s an option with Cree XP-G3.

There are also body options.  What I have here is the aluminum version, which is anodized black.  Also available in copper.  Possibly down the road, other materials will be available too (for example, titanium is mentioned on the box).

Short Review

Fantastic little light.  This is one I’ll keep in a bag, just because it’s tiny and I like the output temperature!  Very versatile UI, too.

Long Review

The Big Table

Acebeam TK16
Emitter: LUMINUS SST-20 (CRI95)
Price in USD at publication time: $54.99
Buy yours at! (Referral link)
Cell: 1×16340
Power Turbo Runtime Eco Turbo Runtime
LVP? Yes
Switch Type: E-Switch
Quiescent Current (A): ?
On-Board Charging? No
Claimed Lumens (lm) 1250
Measured Lumens (at 30s) 995 (79.6% of claim)^
Claimed Throw (m) 118
Candela (Calculated) in cd (at 30s) 370lux @ 4.765m = 8401cd
Throw (Calculated) (m) 183.3 (155.3% of claim)^
All my Acebeam reviews!

^ Measurement disclaimer:  I am an amateur flashlight reviewer.  I don’t have $10,000 or even $1,000 worth of testing equipment.  I test output and such in PVC tubes!!  Please consider claims within 10% of what I measure to be perfectly reasonable (accurate, even).

What’s Included

  • Acebeam TK16 Flashlight
  • Acebeam 550mAh High Drain 16340
  • Spare rubber boot
  • Spare o-rings (2)
  • Manual and warranty card

Package and Manual

The light ships in a nice white package, with a serial number sticker on the back.  I don’t know how to associate this serial with any specific LED option, but the side of the box has that info, seen below.

The manual is very nice.  Two languages are included.  The manual is specific for each emitter type.

Build Quality and Disassembly

The build on the TK16 is quite nice, with nothing glaringly bad to mention.

The light is a bit unusual with the big knurling squares on the body.  These are grippy enough, but cause the light to have a bit of a texture overall that I just wish was…. regular knurling.  If this was regular knurling, with the same diameter of light, I bet there’s an extra mm lost that would have allowed for 18350 cells.  Food for thought.

Though subtle, the tailcap actually has a little lip, which can be unscrewed.  That’s how to replace the rubber boot.  It’s very simple (with no pieces to lose).

The head has some decorative fins but they should do a decent job of cooling, too.

The threads are highly lubed, square-cut, and anodized.  Also note in the picture below, the serial number which you can correspond to your box, which also has the LED information.

The inside of the light:

The tail has a spring, and also due to the electronic switch in the tail, some electronic components, too.  The head has a thin spring, and also what looks like potting, but this seems to be more of a protective sticker than potting or conformal coating.  It’s quite thick – around 1mm, and very flexible.

Despite the bezel unscrewing readily, the optic doesn’t fall out, nor come out easily with persuasion.

The body has an “inner sleeve,” a necessity with the e-switch.  This sleeve does not come out, at least not without completely disassembling the tail of the light.

My only complaint with this light regarding build quality is that the head is just a bit difficult to thread onto the body with the clip in place.

Size and Comps

66.5mm long, 23mm wide (head), and 22mm wide (tail).
Weight: 37.3g

It’s a small light, indeed!

Here’s the test light with the venerable Convoy S2+.  Mine’s a custom “baked” edition Nichia 219b triple.  A very nice 18650 light.

And here’s the light beside my custom engraved TorchLAB BOSS 35, an 18350 light.  I reviewed the aluminum version of that light in both 35 and 70 formats.

Retention and Carry

The only option for carry (aside from naked deep carry) is the included pocket clip.  It’s a friction fit clip, and quite snug.  Technically reversible but in reality, it doesn’t sit properly in the orientation not seen below.  So this is the “right way.”  The mouth isn’t quite as big as I’d like and the bit of the clip that’s attached to the body blocks pockets a little.  It does need that added material some of these types of clips have.  (Sorry, there’s really not a name for it.)

The orientation seen above is bezel up, and not all that deep carry.  Ultimately the clip could be better.

Power and Runtime

The TK16 (all models) is powered by a single 16340 cell.  Acebeam includes a cell, which is 550mAh.  It’s not specifically labeled as a high drain, but I suspect it is.

The cell is a button top.

Here’s the way to put the cell in the light – as usual, the head gets the positive terminal.

The UI is interesting in that there are two mode groups – “Power” and “Eco.”  They differ in the output on Turbo, but also (inexplicably) in the runtimes on a lower mode or two.  I did an extra runtime for this light – both Turbos, and the High mode (which is the same output for both groups).

In every case, the light exhibited LVP.  The differences in voltage at shutoff can be attributed to the operator not stopping the test immediately at shutoff, and allowing the cell to bounce back (sometimes a little, sometimes a lot.)

High is fairly respectably flat, but for only around 25 minutes.  Then the stepdown is dramatic (as on both Turbos.)

The LVP is 2.7V or so.  Note before the massive stepdown, the light flickers warning that the voltage is low.

Modes and Currents

Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens
POWER Turbo 1250 45m 995
ECO Turbo 750 45m 661
High 450 1h (1h15m ECO) 392
Mid 80 3h 64
Low 13 12h 16
Moonlight 0.5 6d ~

Pulse Width Modulation

For reference, here’s a baseline shot, with all the room lights off and almost nothing hitting the sensor.  Also, here’s the light with the worst PWM I could find.  I’m adding multiple timescales, so it’ll be easier to compare to the test light.  Unfortunately, the PWM on this light is so bad that it doesn’t even work with my normal scale, with is 50 microseconds (50us).  10ms5ms2ms1ms0.5ms0.2ms.  In a display faster than 0.2ms or so, the on/off cycle is more than one screen, so it’d just (very incorrectly) look like a flat line.  I wrote more about this Ultrafire WF-602C flashlight and explained a little about PWM too.

User Interface and Operation

The switch on the TK16 is a tail e-switch and has a rubber cover.

The switch is surrounded by a screw-down bezel-like piece, which allows easy replacement of the cover.

Here’s a UI table!

State Action Result
Off Click On (Mode Memory)
Off Hold Moonlight
Off Long Hold Moonlight then Lockout (Triple flash to confirm)
Lockout Long Hold Unlock to Moonlight
Lockout Click 10x Switch Mode Groups between Power and ECO^
Any Double Click Turbo
Any Triple Click Strobe
On Hold Mode Cycle (LMH) (No Moonlight, Turbo, or Strobe)
Special Group (Turbo or Strobe) Hold Low^^
On Click Off

^ Power Group is indicated by a low flash then high flash, then off.  ECO group is indicated by a high flash then a low flash.  The light remains locked even after group change.
^^ Manual has this wrong – seems to say it’ll go back to the memorized mode, but it in fact goes to low.

LED and Beam

In this copy of the TK16, I have the Luminus SST-20 4000K High CRI emitters.  There are three of them, and they’re behind a clear optic.

Below have a look at the two copies I have – on the left is this Osram emitter light, and on the right is the Luminus SST20 option.

These beamshots are always with the following settings:  f8, ISO100, 0.3s shutter, and manual 5000K exposure.

The first 5 modes are all of the outputs of the Power group.  The last (right most) is ECO Turbo, so should be (and is) lower than Power Turbo.

Tint vs BLF-348 ( 219b version) (affiliate link)

I compare everything to the 219b BLF-348 because it’s inexpensive and has the best tint!

Random Comparisons and Competitive Options….

Here’s a link to a relevantly filtered page on  I use that site a lot!  There are a few other Luminus-containing lights, but I’m fairly sure they’re all SST40 lights.


What I like

  • Output is good (doesn’t quite hit specification, but reasonably close)
  • Grossly overperforms throw specification
  • UI is quite versatile, and allows access to low easily
  • Multiple groups, allowing better power management
  • Size and shape
  • Love the warm Luminus SST20
  • Love the High CRI option!

What I don’t like

  • Pocket clip isn’t fantastic
  • It’s not an 18350 light
  • Switching between groups is a bit fiddly


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3 thoughts on “Acebeam TK16 (Luminus) Flashlight Review”

  1. MascaratumBLF

    Lovely flashlight and another awesome review! Will you post it on BLF?
    I guess many of use were/are curious about this light.
    Once it was released in aluminium, I may give it a try, as the UI doesn’t seem to compromise that much for and EDC light!

    BTW, did you try it yet with the Vapcells?
    And another question, sorry if I missed it, can you enter the “regular modes” after getting into Moonlight? Or is ML a separate mode at all?

    Thanks again, good work!

    1. Sorry I missed this comment til today!

      > Will you post it on BLF?

      I can – I don’t usually/always, but if there’s interest, sure!

      > did you try it yet with the Vapcells?

      I can’t recall putting one of the Vapcells in it. Sorry!

      > can you enter the “regular modes” after getting into Moonlight?

      If I recall correctly, Moonlight is sort of playing in its own sandbox here. I’ll check when I get home. Normally I have this light with me (in a bag) but I didn’t bring my bag today!

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