Cyansky K3 V2 Flashlight Review
The Cyansky K3 V2 is an updated flashlight by Cyansky offering a dual switch interface, Luminus SFT-40-W emitter, and tactical features. Read on!
Official Specs and Features
Here’s a link to the Cyansky K3 V2 flashlight product page on aliexpress.
Versions
There’s only one version of the Cyansky K3 V2 flashlight. There is a prior version though of the Cyansky K3 flashlight, which I reviewed a while back.
Price
The Cyansky K3 V2 flashlight sells for $99.95. If you buy the Cyansky K3 V2 flashlight on amazon, you can click a 10% coupon. This price includes the 21700 cell shown in this review.
Short Review
I would say the original K3 was well-built. This updated version is too! Based on how I read the new vs the old version, it looks like v2 essentially gets a spec bump. Higher output, more throw, (and a higher price.) I’ll call this a win.
Long Review
The Big Table
| Cyansky K3 V2 Flashlight | |
|---|---|
| Emitter: | SFT-40-W |
| Price in USD at publication time: | $99.95 |
| Cell: | 1×21700 |
| Runtime Graph | |
| LVP? | Maybe |
| Switch Type: | Both |
| Quiescent Current (mA): | – |
| On-Board Charging? | Yes |
| Charge Port Type: | USB-C (on cell) |
| Charge Graph | |
| Power off Charge Port | No |
| Claimed Lumens (lm) | 2000 |
| Measured Lumens (at 30s) | 1526 (76.3% of claim)^ |
| Candela per Lumen | 75 |
| Claimed Throw (m) | 700 |
| Candela (Calculated) in cd (at 30s) | 4700lux @ 4.937m = 114558cd |
| Throw (Calculated) (m) | 676.9 (96.7% of claim)^ |
| Claimed CCT | – |
| Measured CCT Range (K) | 5900-7000 Kelvin |
| Item provided for review by: | Cyansky |
| All my Cyansky 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.
What’s Included
- Cyansky K3 V2 flashlight
- Cyansky 5000mAh 21700
- Charge cable (USB to USB-C)
- Spare o-rings (2)
- Spare switch cover
- Lanyard
- Nylon pouch/sleeve
- Manual
Package and Manual
Build Quality and Disassembly
As I said above, the Cyansky K3 V2 Tactical flashlight is a very well-built light. Cyansky does this… they build very nice lights! I’ve reviewed a bunch of them, and even in categories I might not chase, it’s easy to note that the lights are still of nice quality.
Below you can see the tailcap removed. The spring is just a little proud (and that’s fine). The threads are square-cut, anodized, and lightly lubed.
Inside the tailcap, you can see that the spring is quite long.
In this updated version, the head does have a spring! This is a good change for this tactical-oriented flashlight.
Size and Comps
Head diameter: 40mm
Body diameter: 24.4mm
Length: 153.6mm
Weight: 132.2g (without cell)
If the flashlight will headstand, I’ll try to show it here. If the flashlight will tailstand, I usually show that here, too.
Here’s the test light with the venerable Convoy S2+. Mine is a custom “baked” edition Nichia 219b triple. A very nice 18650 light!
Also above is 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.
Retention and Carry
You’ll probably notice the pocket clip first, though there are a few options for carry. The clip is a standard friction-fit variety.
This clip fits only on the tail end of the Cyansky K3 V2 tactical flashlight.
Next for carry is the lanyard. You could likely attach the lanyard on the pocket clip, but I’d go with these two holes on the tail end instead.
Finally, there’s this nylon pouch. This is another big change from the previous iteration of the K3. This time we get a full and actual pouch! The light is not to be used while in the pouch.
Power and Runtime
The Cyansky K3 V2 tactical flashlight is powered by a single lithium-ion cell. Cyansky includes an appropriate cell – a 5000mAh 21700, the BL2150U.
As far as usage goes, this is a standard button top 21700. It has some additional features, which I’ll cover below. This is the same cell that’s used in the other Cyansky 21700 cell lights.
The cell fits into the K3 in the usual way – positive terminal toward the head.
Below are a few runtime tests. You’ll note the big stepdown in turbo – I’d like to see this held a bit longer and a bit higher. Also, the subsequent modes are a bit lower than they probably could be. “High” of 400 lumens seems anemic.
In the runtime graphs above, I did not really observe low voltage protection. This is sort of to be expected with a tactical flashlight. The light steps down to “very low output” at around 2.6V and then finally shuts off (ish) at 2.5V.
Charging
As stated, the cell has some other features too. There’s built-in USB-C charging, by way of a USB-C port on the positive terminal end.
Another feature is a little indicating LED right in the positive terminal of the 21700. When charging, this indicator is red. When charging is complete, the indicator is green. Otherwise, the indicator is not on at all.
An appropriate cable is included – USB to USB-C.
Charging proceeds at a fairly slow 1.5A or so, which is well under 0.5C for this 5000mAh cell. The time required is around 3 hours, and the terminal voltage seems to be consistently 4.19V, a very good termination voltage.
C to C charging for the cell looks about the same as A to C.
Modes and Currents
| Mode | Mode Claimed Output (lm) | Claimed Runtime | Measured Lumens | Tailcap Amps |
|---|---|---|---|---|
| Turbo | 2000 | 2h | 1643 (0s) 1526 (30s) |
7.50 |
| High | 450 | 4.5h | 399 | 0.92 |
| Med | 150 | 16h | 146 | 0.30 |
| Low | 30 | 66h | 30 | 0.06 |
| Eco | 2 | 400h | 3 | ~ |
Pulse Width Modulation
No real PWM on any mode. High shows some squiggles, which I don’t believe is PWM.
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
Two switches are used for control of the Cyansky K3 V2 tactical flashlight. First is the mechanical tail clicky. It’s a forward clicky, which allows momentary actuation. This switch also serves as a mechanical lockout to prevent any parasitic drain on the cell
The switch cover is big but the switch itself is normal-sized. It’s not terribly thick, so you can feel the actual switch underneath. The clicky is very clicky and the action is low.
The second option for operation is the e-switch on the side near the head. This switch is metal(ish?) and very proud. Also, it doesn’t compete with anything else, so it’s very easy to find without looking. Notably, this switch (cover) is improved from lights like the H3, which is otherwise a very similar flashlight. Another notable aspect of this V2 edition of the K3 is that this switch has an indication function! Upon powering the light on, the switch will indicate as follows:
Green light: 76-100%
Green light blinking: 51-75%
Red light: 26-50%
Red light blinking: 0-25%
And in my experience, the red light blinking will fade in intensity as the cell voltage continues to get lower.
The user interface is not complicated.
Here’s a user interface table!
| State | Action | Result |
|---|---|---|
| Off | Click Tail Switch | On (last used mode, except strobe) |
| On | Click Tail Switch | Off |
| Off | Hold Side Switch and click Tail switch | On in Eco |
| Off | Click Side Switch | No action |
| On | Click Side Switch | Mode advance L>M>H>T |
| On | Hold Side Switch | Strobe |
| Strobe | Click Side Switch | Return to the previous mode |
For this being billed as a tactical flashlight (and also “looking like one”), it’s surprising that there’s no easy or direct access to turbo or strobe.
LED and Beam
The emitter is a Luminus SFT-40-W. A smooth deep reflector is used here.
The bezel is crenelated, so light will shine out when headstanding (and on).
Again, Cyansky bills this bezel as zirconium, but I suspect it’s just those three-strike points that are zirconium. They aren’t sharp; these are tiny spheres.
LED Color Report (CRI and CCT)
The temperature (CCT) of this SFT-40-W starts around 5900K and as the modes go up, so does the CCT, all the way to nearly 7000K. CRI is low too, at around 70.
Beamshots
These beamshots always have 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 KillzoneFlashlights.com 219b BLF-348 because it’s inexpensive and has the best tint!
Conclusion
What I like
- Great (and improved) output
- Great (and improved) throw
- Simple user interface
- Brand user interface consistency
- Excellent build quality
- Cell is included
- No PWM
- Added an indicating switch
What I don’t like
- Cool white
- No direct access to strobe or turbo
- Price is a little high
Notes
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