acebeam l17 osram white 18650 thrower feature shot laying on side

The great guys over at have the new Acebeam L17 in stock and wanted me to get some numbers on it.  The Acebeam L17 is a thrower flashlight in 18650 format with Osram Flat White.  Read on for some thoughts and testing!

Official Specs and Features

Here’s a referral link to the official product page.


There’s only one body available but four emitter options.  White (seen here), green, red, and blue.

There is an option worth mentioning, too.  For an additional $10, a remote pressure switch can be added to your purchase.


As seen here (in white) the Acebeam L17 is $59.90 at  Illumn also has green, which is also $59.90.

Short Review

I love this light.  The tight beam is ridiculously useful, in ways that might not always be evident.  The build quality is great and the throw is useful.  The price is even great, too!

Long Review

The Big Table

Acebeam L17
Emitter: Osram White (KW CSLNM1.TG)
Price in USD at publication time: $59.90 at
Cell: 1×18650 (or CR123x2)
Turbo Runtime High Runtime
LVP? Yes
Switch Type: E-Switch
Quiescent Current (mA): 0.08
On-Board Charging? No
Claimed Lumens (lm) 1400
Measured Lumens (at 30s) 1023 (73.1% of claim)*
Candela per Lumen 129.4
Claimed Throw (m) 802
Candela (Calculated) in cd (at 30s) 3780lux @ 6.174m = 144087cd
Throw (Calculated) (m) 759.2 (94.7% 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 L17 Flashlight
  • Lanyard
  • Nylon pouch
  • Spare o-ring (2)
  • Spare switch cover
  • Manual and papers

Package and Manual

Build Quality and Disassembly

Absolutely zero complaints about the build quality.  Everything is on par with Acebeam’s other lights, and that’s a good thing.

The Acebeam L17 is very active in hand.  There are lots of grooves or edges or tactical spots or whatever that you’ll always notice.

The tailcap has reeding of appropriate size for easy removal for cell swaps.

The body is surprisingly without any knurling or texture.  Does have branding, though.

The head has both cooling fins, and vertical grooves (three sets).

The tailcap has a beefy spring, and some other electronics happening.  The threads here are beefy too, and anodized, and square cut.  Very smooth threads.

You can see the L17 has an inner tube.  This furthers my belief that the switch is an e-switch.

The head also has a spring.

Due to the strike bezel, light is able to escape when headstanding the L17.

Size and Comps

Official specifications on size are as follows:  140.5mm in length, 40mm in diameter at the head, 25.4mm in diameter at the tail.

If a light will headstand, I’ll show it here (usually the third photo).  If a light will tailstand, I’ll show that here, too (usually the fourth photo).

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.

These two lights look very different from the side, but the optic is the same.  For daily carry I’d probably give the edge to the L17.

Retention and Carry

A belt clip is included and attached to the L17.

The clip is actually captured by the tactical ring.  If you remove the tactical ring, you’ll also have to remove the belt clip.

The belt clip is keyed, too – it rests in a little notch on the body.

acebeam l17 osram white 18650 thrower threads showing with tactical ring off

The light will fit back together fine and work without the tailcap, though.

acebeam l17 osram white 18650 thrower tactical ring off showing pocket clip attachment

There’s also a lanyard loop in the tactical ring.  The tactical ring isn’t keyed, and can be twisted around the light.

Since the belt clip is captured by the tactical ring, it’s a good spot for attaching the lanyard if you wish.  There are two loops on the clip suitable for this.

acebeam l17 osram white 18650 thrower pocket clip lanyard holes

Power and Runtime

The Acebeam L17 is powered by a single 18650 cell.  I tested the light with a flat top unprotected cell but a longer cell would certainly work just fine.  Maybe even better – the cell I used had a little too much room.  Notably the L17 will operate on 2xCR123 as well.

The cell goes into the L17 in the usual way – positive terminal toward the head.  And you can see below the room left over in the cell tube – a longer cell would fit.

Here are a couple of runtimes.  I didn’t see the claimed 1400 lumens, but lights like this (very throwy lights) don’t always read perfectly.  I didn’t test output with CR123x2, so it’s possible the rated specs are only achieved at that higher voltage.

Output falls off quickly for a couple minutes, then levels off, and then steps down dramatically to around 50 lumens.  The L17, like many Acebeams, flashes the main emitter to warn of low voltage, and then does shut off, with proper LVP.

Output on High is very stable, and steps down at just under 2 hours.

It looks like the main emitter warning is actually at the transition from any mode down to the 50 lumen output.  When the light switches down to 50 lumens, it flashes 3x.  The cell at this point is 3.1V (and is essentially depleted, despite still having some operational capacity).

Modes and Currents

Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens Tailcap Amps
Turbo 1400 1h15m 1023
High 370 2h45m 317
Mid 150 6h45m
Low 50 21h
Ultra-Low 15 58h

I wasn’t able to test the current on this light because of the tailcap e-switch setup.

Pulse Width Modulation

No PWM on any mode.

For reference, here’s a baseline shot, with all the room lights off and almost nothing hitting the sensor.  And here’s the worst PWM light I have ever owned.  Also one of the very first lights I ordered directly from China!

User Interface and Operation

The L17 has what Acebeam calls a “soft-touch” tailcap switch.  Based on how it feels, and how the inside of the tailcap looks, I think this is an e-switch (and of course press and hold in the UI confirms that).  It’s quite good, too and Acebeam is right to call it a soft-touch.  The switch is near-silent, and very pleasant to operate.

Here’s a UI table!

State Action Result
Off Hold Ultra-Low
Off Click On (mode memory)
Any Double Click Turbo (Technically on first to mode memory, then turbo)
On Hold Mode advance (LMH only)
Turbo Double Click Memorized mode
Any Triple Click Strobe
Off Hold 3s Lockout
Lockout Hold 5s Unlock to Ultra-Low
On Click Off

Note the easy access to both Turbo (from any state) and Ultra-Low (from off).

LED and Beam

The emitter in the Acebeam L17 is an Osram Flat White.  Specifically this is the KW CSLNM1.TG.  The optic typically used with this emitter is used here too.  It’s the same one (or at least same style) as in the E10 (which I reviewed as well).

This emitter really puts a spot of light out there.  But don’t think this is only for distance use.  Ultra-Low and Low are great for around the house – making sure the doors are locked for example, from across the room.  You really put the light where you want it, and nowhere else with this light!

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

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

I keep the test flashlight on the left, and the BLF-348 reference flashlight on the right.

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


What I like

  • Great spot of light
  • Useful spot of light for even around-the-house use on the lower modes
  • Great User Interface with easy access to Ultra-Low and Turbo
  • The other emitter color options (red, green, blue) – all fun lights!
  • “Big brother” of the E10

What I don’t like

  • Cell isn’t included
  • Supports CR123x2 but not 18350×2.  (And it might well but the voltage range isn’t stated, so try at your own risk).
  • Acebeam branding it as the “Longest throwing tactical 18650 flashlight” – that’s probably true, for now but…

Acebeam is fast becoming one of my favorite production-light manufacturers – if you were to ask me right now I’d probably go on and say it is favorite (ok top 3).  They offer so much, and the L17 is but one more example!


  • This light was provided by for review. I was not paid to write this review.
  • This content originally appeared at  Please visit there for the best experience!
  • For flashlight-related patches, stickers, and gear, head over to PhotonPhreaks, another site where I write!
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