The Acebeam K75 flashlight is a 18650×4 dedicated thrower with a Luminus SBT-90 Gen2. Read on for some thoughts and testing!
Official Specs and Features
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.
I have this light from Going Gear so that’s where I think should get it. Order it through this affiliate link 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!
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.
The Big Table
|Emitter:||Luminus SBT-90 GEN2 (White)|
|Price in USD at publication time:||$321.90|
|POWER Turbo Runtime||ECO Turbo Runtime|
|Quiescent Current (A):||?|
|Claimed Lumens (lm)||6300|
|Measured Lumens (at 30s)||4478 (71.1% of claim)*^|
|Claimed Throw (m)||2500|
|Candela (Calculated) in cd (at 30s)||26100lux @ 7.682m = 1540243cd|
|Throw (Calculated) (m)||2482.1 (99.3% of claim)*$|
|All my Acebeam reviews!|
- Measurement disclaimer: 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).
^ 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…
- Acebeam K75 Flashlight
- Acebeam carry handle for the K75
- Spare o-rings (2)
- 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:
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 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 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.
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 it’s 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 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|
- 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 are 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.
No PWM at all (yay!).
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). 10ms. 5ms. 2ms. 1ms. 0.5ms. 0.2ms. 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
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!
|Off||Click||On (Mode Memory)|
|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*|
|Turbo||Double Click||Previous Regular mode|
|On||Hold||Mode Cycle (LMH) (No Moonlight, Turbo, or Strobe)|
|Special Group (Turbo or Strobe)||Hold||Low^|
- 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.
Tint vs BLF-348 (Killzone 219b version)
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!
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
- This light was provided by Going Gear for review. I was not paid to write this review. Buy this light at their site! (And this is actually a loaner – I was not compensated in any way for this review.)
- This content originally appeared at zeroair.org. Please visit there for the best experience!
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