Acebeam K65 NW review w/ measurements (XHP70.2, 4x18650)

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maukka
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Acebeam K65 NW review w/ measurements (XHP70.2, 4x18650)

Disclaimer: The Acebeam K65 was provided for testing by manufacturer free of charge

With the K65 Acebeam has updated their popular K60 to a more efficient XHP70.2 emitter. It gains significantly more throw with a dedomed version of the LED and a smoother reflector. It’s also a bit smaller than its predecessor and utilizes a single electronic side switch instead of a mechanical rear clicky + magnetic control of the K60.

The K65 is available in neutral and cool white. The version tested here is the NW one.

Manufacturer’s specifications
Battery: 4×18650 (accepts button and flat tops, protected and unprotected, batteries not included)
LED: A dedomed Cree XHP70.2 in neutral 5000K or cool 6500K white
Waterproof: IPX8, 2 meters
Impact resistance: 1.2 meters
Mode memory: yes (except moon, turbo, strobe and sos)
Low voltage protection: side switch led indicator when battery voltage low, LVP cutoff at critical levels
Thermal regulation: yes
Lockout: electronic and physical
Working voltage: 12V to 16.8V

Output specs
Maximum output: 6200 lumens (stepdown to 4000 lumens at 3 minutes)
Other output levels: 3500/1700/700/250/5 lumens
Light intensity: 257000 candela
Beam distance: 1014 meters
Special modes: strobe, sos

Measured dimensions and weight
Length: 191mm
Head width: 90.3mm
Handle width: 53mm
Weight: 647g plus 187g for the batteries

Box and contents
Acebeam has added some color to its bigger cardboard boxes as well.

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

Here’s the user manual

Note that there are some errors in the UI chart. Refer to bugs and actual usage in a chapter below.

Physical appearance


The reflector is quite smooth, with just a tad of orange peel. Just like the later model K60s and K70s the bezel has inner threads for attaching FR10 series red, green and orange filters or a diffuser.


The battery carrier (4 batteries in series) 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.

There’s no electrical pathway in the handle itself and it doesn’t matter which way you insert the carrier into it. Just make sure you use correct polarity when inserting the batteries in the carrier itself. Protected batteries are recommended since they are configured in series. Or at least use a matched set with the same type and age.

In addition to electronic lockout you can physically lock out the light by opening the battery tube half a turn.

The knurling isn’t very aggressive and feels quite smooth.


The nylon holster is of good quality and identical to the one that came with the K60.


The rear of the light is flat for stable tail standability.


There’s a tripod screw hole on the body. Large mounting plates will not fit though, since they’ll hit the wider head.


K65 on the right next to the K60.

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.

Some people will probably miss the magnetic control ring of the K60, but I like a good eswitch better. It means I don’t have to change my grip to turn the light on and can access turbo faster without trying to turn the ring to a certain position. These are subjective of course.

From off:
Click side switch to turn on the light on the last mode used (ultralow, low, mid, high)
Double click for turbo
Triple click for strobe
1 second long press for lowest output (eco), long press to advance to low (bug, should go to ultralow)
2 second long press for SOS, long press to advance to low
6 second long press for lockout mode, 3 second long press to unlock

From on:
Click to turn off
Hold switch to advance to the next mode (ultralow-low-mid-high-ultralow…)
Double click for turbo, another double click goes back to previous mode, long press goes to ultralow
Triple click for strobe

I think the new UI is one of the best single electronic switch implementation available and a huge step up from the previous Acebeam UI.

No more extra double click for the maximum output, since the normal mode cycle now has four modes instead of three. I also like the fact that you can get to either ultralow or previous selected mode from turbo depending on if you long press or double click.

There was one small bug in the UI though. If you select the moonlight/lowest mode (ECO) by a long press from off, then proceed to advance to the next mode with a press and hold the light skips the next mode (ultralow) and goes straight to low. SOS also goes to low with a long press, but I don’t see that as a problem.

I would also like to have the battery indicator or the main led flash if you’re trying to turn the light on when it has been locked out electronically. It could be confusing as to why the light doesn’t work.

Beamshot comparison

I took beamshots comparing the K65 to two other similarly sized XHP70 lights. My Acebeam K60 has a CRI90 5000K XHP70 and the Convoy L6 has a stock neutral white (3A) emitter. On both the dome has been shaved off with a razor blade.

The K60 is my current reference on how good an XHP70 can be. I’ve not seen anything like it and the great tint and lack of tint shift should be evident in the images.

The almost smooth reflector of the K65 combined with the XHP70.2 results in a strong yellow corona around the hotspot. The hotspot is very tight considering the large die size and its tint is quite alright on the higher modes. The spill is very good as well thanks to the dedoming. There’s no blue or purple on the spill like on the domed XHP70.2 of the K30.

Individual beamshots


Individual beamshots


Individual beamshots


Beam and tint

Tint within the beam (on medium):

Tint in the hotspot in different modes:

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

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
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.

CRI data on turbo from the hotspot

CRI data on medium from the hotspot

Output and runtimes

All tests were done with a set of unprotected button top Samsung 30Qs.

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 time when the l ight steps down depends on environmental factors.

The K65 is very efficient at 132lm/W at over 1400 lumens.

If cooled properly, the K65 will stay on turbo until the batteries run out.

All the modes are fully regulated as long as the light doesn’t heat up too much. Thanks to the 4S 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: 68µA
Electronic lockout: 68µA

It would take over 6 years to drain three 3000mAh batteries in standby mode, which is slower than the self discharge rate of 18650s.

Low voltage protection

When the battery pack voltage drops below a certain threshold, the side led turns red, then blinks in red and finally the light shuts off. The thresholds are as follows:

Green: 12.7-16.8V
Red: 11.6-12.7V
Blinking red: 11.2-11.6V
Low voltage shutoff: 11.2V (2.8V per cell)

Flicker

I measure the flicker optically from the LED with a Thorlabs DET36A/M photodetector and an oscilloscope.

There’s very high frequency (142kHz) ripple but no visible PWM on any mode. The flicker snob index of 0.0% indicates that there’s no fear of noticing it at all.

Other modes:
Eco:“https://i.imgur.com/W5vV3gX.png”
Ultralow:“https://i.imgur.com/JMDiXhM.png”
Medium:“https://i.imgur.com/eMTgxcy.png”
High:“https://i.imgur.com/nvMTrVl.png”
Turbo:“https://i.imgur.com/vWAlB2T.png”

Strobe

Strobe operates at 8 hertz and equals turbo in output (not medium like Acebeam says)

Here’s strobe first and turbo after it.

Temperature

Like most Acebeams there’s thermal regulation in the K65 to protect the emitter and driver. It isn’t very aggressive. It is up to the user to lower the level when they start feeling uncomfortable.

The light does step down at about 6 minutes when the handle reaches 48°C. The hottest point of the head is at 58°C when this happens. The stepdown isn’t enough to stop the heating up and the light gets progressively hotter and reaching battery scorching temperature of 70°C in the handle at 50 minutes.

However, in a cold environment or with enough airflow the light may not step down at all on turbo.

In room temperature (24°C)) on high the light reached 50°C in 15 minutes and tops out at 70°C.

On medium mode the light only reached 41°C.

Verdict

Pretty much all the praise I gave to the Acebeam K30 goes for the K65 as well. They’re both excellent performers with great feeling of quality. They make good use of power with high efficiency drivers and regulated output on all modes. The temperature regulation works great and doesn’t limit output prematurely.

The K65 also goes one step forward with a new electronic switch UI. There’s no more awkward double double clicking for maximum output and they’ve ironed out almost all of the bugs. As it stands it’s one of my favorites.

The dedomed XHP70.2 has a couple of advantages compared to the stock domed version. The hotspot is well defined in the almost smooth reflector of the K65 and the spill is not purple at all. There’s a good mix of lumen output and throw.

There’s still the big unattractive yellowish corona around the greenish hotspot though. Cree is still behind Nichia in tint and I’d like to see some manufacturer experiment with the 144 series, which can look great with a matched reflector.

+ Very high output for a single emitter light
+ Excellent efficiency
+ Regulated output as long as the temperature stays within safe limits
+ Great new single switch UI
+ Excellent finish and quality
+ Battery carrier accepts all kind of 18650s
+ No visible flicker
- Small UI bug when advancing from eco to the normal mode cycle
- Greenish tint
- Strong yellow corona around the hotspot
- No indication of electronic lockout when trying to turn on the light

Edited by: maukka on 01/22/2018 - 03:02
AlexGT
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Thank you for the review, Can you tell how the K65 LED was dedomed? Was it a chemical dedome or a shave dedome? It looks like a chemical dedome to me, but want to confirm… Any closeup pic of the LED?

maukka
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It certainly looks chemically dedomed. No sign of silicone left.

maukka
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Got information from Acebeam, that the dome is very closely shaved off. They’ve done a great job at it.

will34
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Thanks for the detailed review. I had very high hopes for this light but as a thrower, that yellow corona is unbearable to my eyes. It doesn’t seem to perform better than the much older TN40S.

KawiBoy1428
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I have completely de-domed the 70.2 before, it was relatively easy chemical process, I used a P2-1C and put it in a T90-2 at 12v 8amps 3-4S, but the very smooth reflector showed many anomalies, the cross was more prevalent and the corona was repulsive and tint shift was way too yellow in the lower modes. I have seen improvement in the Turbo level but not enough to justify me using it. Maybe Acebeam solved this with the Higher current and lightly OP reflector.

You can see the de-domed 70.2 at the far lower right of my de-domed emitter box on the 12v Sinkpad mcpcb.

I might try again with a different emitter, a higher temp/kelvin emitter?

Also wondering what chemical/ process they used to de-dome?

Great review, very informative! Acebeam seems like they are on the cutting edge and is not afraid to push the limts a bit! I too am glad Acebeam went away from the selector ring! KISS!

KB1428 “Live Life WOT”

Gee858eeG
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Just wanted to leave a thanks @maukka!

Thanks

Flash Voyager
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Hi,
thanks for the great review!

Is the hotspot homogeneous or visible some light strip/flow maybe different colours inside that (because of the smooth reflector) on the white wall?

Hardusvd70
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Thanks for this brilliant review. When you going to test the new BLF GT?

Hardusvd70

maukka
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I am not really set up for testing the GT. The head is too large for the sphere and the candela measurement needs a lot of space.

And the fact that I still haven’t even gotten the light, tracking code or any reply from Neal, even though I was among the first 100 to pay for it, makes it kind of impossible to even consider testing it Wink

the4ds9
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Thank you maukka for this much-needed review. I just purchased Sony VTC4 cells from Battery Junction because they are very powerful and yet budget-priced. I am so excited to turn them on outdoors in the darkness and vast wilderness where targets are measured in tenths of a mile and not yards! Go Acebeam K65 + Sony VTC4 all the way baby!

ARsee
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Nice review of a nice light.
Thanks maukka Thumbs Up

WaylonJennings
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maukka wrote:
I am not really set up for testing the GT. The head is too large for the sphere and the candela measurement needs a lot of space.

And the fact that I still haven’t even gotten the light, tracking code or any reply from Neal, even though I was among the first 100 to pay for it, makes it kind of impossible to even consider testing it Wink

Great review as usual, thanks.

If the shipping cost were not so high I would send you my GT.

You Output and run time chart is labeled K60. Are they actually the numbers for the K65?

maukka
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WaylonJennings wrote:
If the shipping cost were not so high I would send you mine.

Thanks, but it finally arrived Smile

Maverick1947
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Hello! Where can I find a XHP70 CRI90 to buy?? I cannot find it anywhere. I would love to swap it in my L6.

There’s no replacement for displacement.

maukka
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Maverick1947 wrote:
Hello! Where can I find a XHP70 CRI90 to buy?? I cannot find it anywhere. I would love to swap it in my L6.

Mouser has the XHP70 in CRI90, but for XHP70.2 you need to buy the whole reel.

Here’s 5000K:
https://br.mouser.com/ProductDetail/Cree-Inc/XHP70A-01-0000-0D0UJ450G?qs...

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Thank you! I will be looking into it.

There’s no replacement for displacement.