Acebeam K30 NW review w/ measurements (XHP70.2, 3x18650)

Wurkkos

maukka

Enlightened
Joined
Dec 22, 2015
Messages
644
Location
Finland
Disclaimer: The Acebeam K30 was provided for testing by manufacturer free of charge

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The Acebeam K30 is one of the smallest, lightest and brightest 3x18650 single emitter lights on the market. It sports a powerful XHP70.2 LED with an output of 5200 lumens.

According to Acebeam the K30 is their most durable flashlight to date. Even if the K30 is not a diving light and shouldn't be operated under water they give it a waterproof rating of 5 meters submerged or up to 10 meters momentarily. Impact resistance is typical at 1.2 meters though.

The K30 is available in neutral and cool white with either a black or sand finish. The version tested here is the NW one.

Manufacturer's specifications
Battery: 3x18650 (accepts button and flat tops, protected and unprotected, batteries not included)
LED: Cree XHP70.2 in neutral 5000K or cool 6000K white
Waterproof: 5 meters
Impact resistance: 1.2 meters
Mode memory: yes (except moon, turbo and strobe)
Low voltage protection: side switch led indicator when battery voltage low, LVP cutoff at 8.5V (2.83V per cell)
Thermal regulation: yes
Lockout: electronic

Output specs
Maximum output: 5200 lumens (stepdown to 2000 lumens at 2 minutes)
Other output levels: 2500/1350/600/200/2 lumens
Light intensity: 35000 candela
Beam distance: 374 meters
Special modes: strobe, sos, beacon

Measured dimensions and weight
Length: 119mm
Head width: 48.2mm
Handle width: 43.1mm
Weight: 171g plus 140g for the batteries

Box and contents
Acebeam has really upped the game when it comes to presenting their products in retail boxes. Nice stylish container with magnets is a big step up from the brown box.

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Bundled in the box with the light:
Lanyard
Holster
Two spare o-rings
User manual
Warranty card and a lithium ion battery warning

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Physical appearance

The K30 is a bit slimmer than a soda can, so they call it energy drink sized. The head is just 5mm wider than the body, but visually the light is pretty much a cylinder. The design is restrained but stylish. The best thing is the size though. It fits your hand perfectly and is very light for a 3x18650 flashlight. Balancing is great too. I had no problem carrying it with me for extended periods.

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User interface

The light is operated via an electronic side switch. There's an indicator LED next to it to tell you that the batteries are running low.

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Green: >10.5V
Red: 9.5-10.5V
Blinking red: 8.5-9.5V
Low voltage shut off: <8.5V (2.83V per battery)

From off:
Click side switch to turn on the light on the last mode used (low, mid, high)
Double click for turbo, two additional fast clicks for turbo max (light turns off briefly between clicks when activating turbo or turbo max)
Triple click for strobe
Long press for firefly mode
3 second press for lockout mode or unlock, light flashes twice to verify lockout mode, another 3 sec press to unlock

From on:
Click to turn off
Hold switch to advance to the next mode (low-mid-high-low...)
Double click for turbo, additional double click for turbo max
Triple click for strobe

From firefly:
Click to turn off
Hold switch to return to normal mode cycle (next mode memory bug)

From turbo or turbo max:
Duble clicks alternate between turbo and turbo max
Hold switch to return to normal mode cycle (next mode memory bug)

While the mode memory on the main modes works fine, there's three next mode memory bugs in the UI:

1&2. When you return to turbo from turbo max with a double click, then hold the button down to return to the normal mode cycle the next double click will go straight back to turbo max, not to turbo first. But if you return to the normal mode cycle from the turbo max, then the next double click will activate turbo. Also, when returning to the normal mode cycle from turbo or turbo max, it selects the next mode from previously used:

It works like this:
Low (2x click) turbo (hold) mid (2x click) turbo max
When it should be:
Low (2x click) turbo (hold) low (2x click) turbo

Another example:
High (2x click) turbo (2x click) turbo max (hold) low (2x click) turbo
Should be:
High (2x click) turbo (2x click) turbo max (hold) high (2x click) turbo

3. If you start the light on firefly with a long press and the previously used normal mode was low, it jumps to mid after you hold the button from firefly. If the memorized mode is mid it advances to high. From high it goes to low:

Low (click) off (long click) firefly (long click) mid
Mid (click) off (long click) firefly (long click) high
High (click) off (long click) firefly (long click) low

Should remember the mode:
Low (click) off (long click) firefly (long click) low

Size and beamshot comparison

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BLF Q8 (4x18650), Acebeam K30 (3x18650), Thorfire TK4A (4xAA), Convoy S2+ (18650)

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The Acebeam has a bit more of a golden tone to it than the sand Convoy S2+.
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Individual beamshots
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Beam and tint

I have a new setup for more accurate characterization of the beam. The beam properties were measured by controlling a small servo with a computer (Pololu Micro Maestro + Futaba S3151). The flashlight under test was attached to the servo with a rubber holder and a velcro strap. The servo was turned one degree at a time and a measurement was taken with the i1Pro spectrophotometer between the turns. The process takes about 15 minutes and it was repeated twice. The results are the average of these two cycles.

The floody beam profile has a distinct tint shift from the greenish hotspot to the even greener corona and purplish spill we have come to expect from Cree's latest offerings. You either can't stand it or you don't mind. But it's there. It's much less noticeable in actual use, but very visible when shone on a flat surface, be it a white wall or ground - especially snow covered.

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Tint within the beam:
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Tint in different modes:
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Spectral data and color rendering

For spectral information and CRI calculations I use an X-rite i1Pro spectrophotometer with HCFR, Babelcolor CT&A and ArgyllCMS spotread for the graphs and data. For runtime tests I use spotread with a custom script and an i1Display Pro because it doesn’t require calibration every 30 minutes like the i1Pro.

Explanation of abbreviations (click link to read more)

CCT = correlated color temperature, higher temperature means cooler (bluish)
CRI (Ra) = color rendering index consisting of 8 different colors (R1-R8), max value 100
CRI (R9) = color rendering index with deep red, usually difficult for led based light sources, max value 100
TLCI = television lighting consistency index, max value 100
CQS (Qa) = Proposed replacement for CRI, RMS average of 15 color samples
CRI2012 (Ra,2012) = Another proposed replacement for CRI, consists of 17 color samples
MCRI = Color rendering index based on the memory of colors or 9 familiar objects
NEW Read more about the IES TM-30-15 method here (link is external)
TM-30 = The newest color rendering method using 99 samples. Preferred for comparing LEDs.
TM-30 (Rf) = Accuracy of colors, fidelity index. Replaces CRI(Ra).
TM-30 (Rg) = Gamut of colors, saturation index. Higher number means more saturated colors.
Tint dev. (“Duv” in the CTA screenshots) is the tint’s distance to the black body radiator line in the CIE graphs. The higher the number, the greener the tint. 0,0000 means absolutely neutral white and negative numbers mean rosy/magenta tint. Anything over 0,0100 can be described as visibly green.

If you have an hour to spare, I recommend watching this presentation on IES TM-30-15 which also shines light into color rendering in general.


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CRI data on turbo max
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CRI data on mid
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Output and runtimes

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All tests were done with a set of unprotected button top Sony VTC6s.

The actual output falls a bit short of the advertised values, but some of the difference can be accounted to the cool white vs. neutral white output.

The K30 is very efficient at 130lm/W at over 1000 lumens.

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All the modes are fully regulated as long as the light doesn't exceed 75°C. After thermal stepdown it will not fully bounce back to the original level even when cooled but has to be reset. Thanks to the 3S battery config and a 6V emitter, the maximum output is always available throughout the battery life.

Standby drain

There's insignificant parasitic drain on the batteries when the light is switched off. It doesn't change when the electronic lockout is enabled.

Normal standby: 65µA
Electronic lockout: 65µA

It will take about 5 years to drain three 3000mAh batteries in standby mode, which is slower than the self discharge rate of 18650s.

Flicker

I measure the flicker with a Thorlabs DET36A/M photodetector and an oscilloscope. I transfer the scope's sample memory via LAN to the computer where a script parses, performs an fft and other calculations to spit out a bunch of metrics. Then another script draws a graph which represents the output of the light source relative to time. This graph also has the metrics calculated previously.

Here are the metrics:

Frequency – the rate of flicker in hertz. If this is over 10kHz, there's usually no reason to worry about visible flickering
Modulation – also known as percent flicker which is calculated by (max level – min level) / (max level + min level). 100% modulation means that the light is turning completely off during the cycles like on PWM controlled output
Duty cycle: the relative time the light spends above the mid level during one cycle. 50% means that the light is above mid (“on”) 50% and below mid (“off”) 50% of the time. Lower duty cycle results in more visible flickering or strobe effect
Index: flicker index is calculated using the area under the curve (link is external). This integral is separated into area above and below the average output. The index is the area above that average divided by the total area. A pwm light with a duty cycle of 50% will have a flicker index of 0.5, but it is more useful with more complicated periodic waveforms, especially those whose modulation is less than 100%.

Snob index: a rating, which tries to convey a single number of flicker visibility
<1% - Could be considered flicker free unless photographed with a super high shutter speed with the camera stuck on the LED
1-5% - Probably not visible to the naked eye (high frequency PWM, >10kHz or low modulation at lower frequencies)
5-10% - Might be visible to the most sensitive people who know what to look for and try hard enough (incandescent)
10-20% - Sensitive people will see it at least on bright reflections, probably not a dealbreaker yet in general use
20-50% - YMMV area. If you can usually spot mid frequency PWM, you'll easily see the flicker
>50% - Visible to most people at least on some occasions (low frequency PWM, <200 Hz)

There's some ripple on all the modes, but nothing to worry about since it is high frequency and lod modulation. I couldn't make it visible even with a cellphone camera held right down on the lens.

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Low
Mid
High
Turbo
Turbo Max

Strobe operates at 12.5 hertz.
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Temperature

There's thermal regulation in the K30 and it isn't very aggressive. The light gets hot, but protects itself from damage. It is up to the user to lower the level when they start feeling uncomfortable.

I measured 63°C from the handle and above 70°C from the head on turbo max. On turbo before the stepdown the light is even hotter, 65°C on the handle, before it starts to decrease output at about 45 minutes. In a cold environment the light may not step down at all on turbo.

On high the light reaches 51°C which is barely holdable.

Verdict

Everything about the K30 oozes attractiveness. It's compact, light, very nicely machined and the sand finish is absolutely beautiful. The system as a whole is very efficient reaching 140 lumens per watt on the mid mode of 500 lumens.

The ingenious fixed battery carrier has long but hefty springs with the perfect sizing. It fits all types of 18650s from the short flattops to the longest protected button tops with no issues. For modding, there is some work to be done, since the screws have glue on the end.

The only thing that lets it down is the combination of smooth reflector and the XHP70.2. Together they produce an inconsistent tint with a greenish hotspot and purplish spill.

+ Very high output for a single emitter light
+ Excellent efficiency
+ Regulated output as long as the temperature stays within safe limits
+ Perfect form factor, light and compact
+ Beautiful finish and attractive color of the sand
+ Innovative battery carrier with minimal losses, accepts all kinds of 18650s
+ No visible flicker
- UI bugs related to mode memory
- Greenish tint
- Tint inconsistency within the beam
 

easilyled

Flashaholic
Joined
Jun 25, 2004
Messages
7,252
Location
Middlesex, UK
Thanks for the excellent, comprehensive review. I purchased a 6000K black-anodised K30 about 6 weeks ago and am very happy with it. There is definitely a very noticeable tint shift from hotspot to corona to spill as you described. At the higher levels, there is far less of the greenish tint in evidence and its almost pure white to my eyes. This may be expected for a 6000K led. Its certainly a real powerhouse with stunning output for such a light, compact flashlight and the ability for it to tailstand very securely is a big bonus for me as it can deputise as an excellent nightlight, particularly with the firefly level of 2 lumens which actually looks brighter than that to me.
 

Tricolour

Newly Enlightened
Joined
Jan 11, 2018
Messages
6
Location
Adelaide
Thanks M,

An excellent review of what looks like a great performer.

Based on your review I have just ordered one today as I need a torch that will light up plant rooms and large roof spaces.

Also one that I know will keep its charge if not used for a while as this was something that let me down with my TM 06 (I have to keep the barrel unscrewed if I want to eliminate the parasitic draw).

I will let you know what I think of the K30 when it arrives.

E.
 
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