Acebeam K75 Flashlight Review

The Acebeam K75 flashlight is a 18650×4 dedicated thrower with a Luminus SBT-90 Gen2.  Read on for some thoughts and testing!

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Official Specs and Features

Here’s a referral link to the Acebeam K75 Flashlight product page.

Versions

There’s only one body here but there are two emitter options.  There’s the LUMINUS SBT-90 GEN2 (WHITE) (seen here), and the LUMINUS SBT-90 RED.

Price

Order the Acebeam K75 through this affiliate link to KillzoneFlashlights.com so they’ll know I sent you.  The price there is $279.90, and that’s a bit of a sale price.  Or just click it!  That’ll help, too!

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Short Review

First of all, this light hits the claim of 2500 meters of throw.  That’s most important.  Secondly, this handle is awesome.  I can’t see a temperature claim for the emitter but the only thing that might make the light more appealing would be a warmer emitter (and I’m not even sure if that’s an option in this Luminus).  This is a fantastic light.

Long Review

The Big Table

Acebeam K75
Emitter:	Luminus SBT-90 GEN2 (White)
Price in USD at publication time:	$321.90 at killzoneflashlights.com
Cell:	4×18650
POWER Turbo Runtime	ECO Turbo Runtime
LVP?	Yes
Switch Type:	E-Switch
Quiescent Current (A):	?
On-Board Charging?	No
Claimed Lumens (lm)	6300
Measured Lumens (at 30s)	4478 (71.1% of claim)^ ^^
Claimed Throw (m)	2500
Candela (Calculated) in cd (at 30s)	26100lux @ 7.682m = 1540243cd
Throw (Calculated) (m)	2482.1 (99.3% of claim)^$
All my Acebeam reviews!

^ Measurement disclaimer:  Testing flashlights is my hobby. I use hobbyist-level equipment for testing, including some I made myself. Try not to get buried in the details of manufacturer specifications versus measurements recorded here; A certain amount of difference (say, 10 or 15%) is perfectly reasonable.
^^ I wouldn’t worry too much about me reading 71% of the claim here – extremes don’t always work so well in amateur setups like mine.  So extreme throwers (like this one) and extreme flooders (like a Meteor or something) might not read exactly right.  Don’t worry about it.
$ Throw is much easier to measure accurately with an amateur setup…

What’s Included

• Acebeam K75 Flashlight
• Acebeam carry handle for the K75
• Spare o-rings (2)
• Lanyard
• Manual and papers

Package and Manual

Big ol box which itself has a carry handle.  The box has lots of info, including (below) the emitter choice (white or red) labeled.

The light is held in place with foam, very securely.

And one final piece of packaging; this lens cover.

A good manual follows:

Build Quality and Disassembly

The K75 is a big hefty light and has what I’d call Acebeam’s trademark knurling on the body and tailcap.  There are a few nice touches on the K75, most of which will be covered more later.

The body has some fairly thick cooling fins, and there are even some additional up the reflector body.

The parts you’ll need to grip for cell changes are easy to grip, with this big knurling.

The switch is also a nice touch – I like metal switches, and this one doesn’t disappoint.

There’s a bit of branding on the tailcap.  Plenty of room for it.  And the lights are serialized, too.

The tailcap is a “dumb” tailcap – no electronics or anything but metal going on here.  The threads are anodized, square-cut, and well-lubed.  The water sealing o-ring lives very securely and comfortably there, too.

Below is the battery indicator.  More on that later.  It’s a very visible light though.  Not bright, but very evenly lit, and well-executed.

The included lanyard attaches through either of these two holes on the tailcap.  If you run the light with the handle, you could also attach the lanyard there, too.

The head end has a beefy spring and has both positive and negative contacts.

The battery holder tube is fully removable but is directional.  As you can see the right side below is a bit longer – that’s the tailcap end.

The threaded hole you see below is directly opposite the switch.  The K75 also has an indicating function, which you can see at left of the threaded hole below.  That means it’s directly between the handle and switch.

This awesome handle below.  More on that later.

Size and Comps

Officially the K75 is:

218mm long
126mm in diameter at the bezel
53mm in diameter at the tailcap

and weighs 843.8g without cells.

Not at all a small light.  But for 2500m of throw, it’s what we expect.

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.

Here’s the K75 beside the BLF GT – aka Giggles.  Giggles is bigger in all regards as far as I can see.  Also, Giggles throws less far, but is available in NW and is sometimes available cheaper.  But it doesn’t have a handle….  Did I mention I love the handle on the K75?

Retention and Carry

If nothing else than a simple novelty, the primary means of carrying the K75 has to be this awesome handle.  The handle is aluminum and has an obvious install direction….

Below see the WRONG WAY to install this handle.  Again this is wrong.  Backward – I did it incorrectly during the photo session and had to go back to get corrected photos.

Here (below) is the right way.  It’s backward to what I’d expect but it is the actual right way.

And here’s how to know it’s the right way.  When oriented properly, the handle bites the lip of the body, and will not rotate.  When installed incorrectly (as seen before), the handle will rotate freely and can (read: will) unscrew.

The neat thing about when the handle is installed properly?  The light can fully rest on the handle, as a stand for the K75.  I love this level of planning!  One other neat thing about the handle?  I’m pretty sure it’s a Picatinny rail mount!

The K75 is a blast with the handle in place.  One more thing about this handle – the threads and screw that hold this in place is a standard tripod mount screw.

One noteworthy aspect of this handle is it, like the tailcap, is “dumb” – there are no electronics at all here.  Even further to that point, the switch is opposite the handle.  So….  essentially it takes two hands to use the handle and switch modes.  I appreciate the simplicity (because it probably adds robustness) but it’s cumbersome to change modes while using the handle.

There’s a lanyard included, which I mentioned above.  There are a number of ways to attach the lanyard.  Through the tailcap.  Through the attached handle.  But probably best would be to attach through the screw that holds the handle in place.  This screw has a loop too, and probably the best location for attachment.

There’s nothing else for retaining or carrying this light.  There is no pouch.

Power and Runtime

The Acebeam K75 is powered by four 18650 cells.  Four are required, and they fit into the cell holder below.

The cell holder has a “SIDE-A” and “SIDE-B” but overall it seems non-directional.  Two cells go up and two cells go down.  Just always match your cell negative end with a spring and you’ll be good.

There is no direction arrow, and also the sides seem exactly the same entirely.

I used in my testing four protected MJ1 cells from LiionWholesale (reviewed here).  I’m extremely satisfied with those cells, and I can easily recommend them for you to use in this light.  But the light isn’t particular.  You could use any format 18650 you have.  Button top, flat top, protected or unprotected.  Longer cells will be a little harder to get into the bays.  Even these protected MJ1’s are a bit long, but they fit (and I didn’t have to use tools to get them in or out).

That said, on the highest output, the light will want 10A or so (claimed).  So whatever cell you do land on, make sure it’s a capable cell.  And since the cells are in series, each cell needs to be able to output max current.  Also, I’d strongly recommend you use married cells.

(And just in case you’re worried about these protected cells being able to do 10A, in my testing these could output 10A for over 10 minutes, long after the light has stepped down because of temperature.)  Just to be certain about this, I’ll circle back and test output with unprotected 30Q cells and see if that changes the max output.  I’ll update if it does.

There’s a massive stepdown to over 2000 lumens on the highest Turbo (POWER Turbo).  Kind of expected – this mode creates a lot of heat, and that has to be managed.

The second-highest output (ECO Turbo) is almost perfectly regulated and heat never becomes an issue whatsoever.  This is very good, and it makes the two-mode groups a smart addition.  And while on other lights with this UI (TK16 for example) I’d probably skip the ECO, on the K75, I’d probably just always leave the light in ECO.  That way, for every mode available throw will always be its maximum.  That is, on any mode, at no point will the light step down and give you reduced output (ie reduced throw).

One more test for the fun of it… the third-highest mode, which is back in the POWER group.  POWER High – again remarkably flatly regulated, until it shuts off to protect the cells.

One more power-related feature is the power indicator, somewhat beside the switch.  When the light is on, this indicator is on.

It indicates as follows:

Green steady: battery voltage ≥ 12.8V
Red steady: battery voltage within 12.8~12.0V
Red flashing: battery voltage <12.0V

If the battery falls below 11.2V, the light will shut off.  Since these 4 cells are in series (and also why the light requires 4 for operation), this means the light should shut off when the voltage is around 2.8V per cell.  This is well within the acceptable range.

The battery indicator was confirmed with bench power and is all accurate per the manual.

Modes and Currents

Mode	Mode Claimed Output (lm)	Claimed Runtime	Measured Lumens	Tailcap Amps
POWER Turbo	6300	1h45m	4478	>1^
ECO Turbo	3000	1h45m	2177	>1^
POWER High	2500	2h15m	1758	1.040
ECO High	1700	3h30m	1228	0.671
POWER Mid 2	1250	5h15m	899	0.470
ECO Mid 2	600	10h30m	452	0.234
POWER Mid 1	380	16h	275	0.154
ECO Mid 1	250	21h	177	0.116
POWER Low	150	27h	135	0.096
ECO Low	150	27h	87	0.077
Moonlight	7	7.5d	4	0.018

^ My power setup doesn’t allow me to read higher than 1A in an 18V setup.

You’ll note something about this chart – and I noticed it in use, too.  In the manual, the lower two modes for each group match 7 lumens, and 150 lumens.  In practice (on the lux tube and current meter both), ECO and POWER Low mode is clearly different.  The manual’s just a little wrong and that’s fine – I’d rather it be this way really.  Why duplicate these modes, and in practice, they aren’t duplicated.

Pulse Width Modulation

No PWM at all (yay!).

Power Modes:

Eco Modes:

Here you can see a “baseline” – a chart with almost no light hitting the sensor.

Then there’s the Ultrafire WF-602C flashlight, which has some of the worst PWM I’ve seen. It’s so bad that I used a post about it to explain PWM! Here are multiple timescales (10ms, 5ms, 2ms, 1ms, 0.5ms, 0.2ms) to make comparing this “worst” PWM light to the test light easier. That post also explains why I didn’t test the WF-602C at the usual 50us scale.

User Interface and Operation

There’s just one switch on the K75.  It’s a metal-covered e-switch, and the pad is plenty big.  I like metal-covered e-switches!  This one is no exception, too.

I find the switch just a little mashy….  particularly when switching between POWER and ECO – that’s a bunch of clicks.

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
Turbo	Double Click	Previous Regular mode
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

The emitter here is quite unusual.  It’s a very made-for-throw emitter.  This is the Luminus SBT-90 Gen2.  This emitter boasts an emitting area of 9mm^2.  Another common throwing emitter is the Cree XHP35 HI, which has an emitting area of around 11.9mm^2.  What does that mean exactly…  Well, a point source of light will be a better thrower.  So this emitter having a smaller emitting surface means by nature it’ll throw better (at a given output) than something like the Cree XHP35 HI.

And it does throw well.  Of course, the big deep reflector helps that.  The reflector is very smooth and has an ever so slight texture, too.  That makes a beam with an extremely defined hotspot.  On the higher modes some spill can be noticed but really, this beam is pencil-thin spot.

These beamshots are always with the following settings:  f8, ISO100, 0.3s shutter, and manual 5000K exposure. These photos are taken at floor level and the beam hits the ceiling around 9 feet away.

Tint vs BLF-348 (KillzoneFlashlights.com 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 Killzone 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 parametrek.com.  I use that site a lot!  So far this light is the only light using the SBT-90 Gen2!

Conclusion

What I like

• Absolutely massive throw
• Very nice switch
• I absolutely love this handle
• Reasonably priced for such a thrower
• I mean…. this is a singularly impressive light.  Just absolutely impressive.

What I don’t like

• Switch exactly opposite the handle
• Less than desirable tint from the SBT-90 Gen2

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Notes

• This light was provided by Going Gear for review. I was not paid to write this review.  Buy this light at acebeam.com!  (And this is actually a loaner – I was not compensated in any way for this review.)
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