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Nitecore has been a respected name in flashlights for quite some time, always being one of the first to incorporate new technologies into flashlights. As a part of it's Explorer series, Nitecore has released the EC25, a "palm-sized searchlight", naming it the Cobra for the distinctive shape of it's head.


Thanks to Nitecore for providing the Cobra for review.

I’ll be reviewing the Cobra in two sections: first, I’ll discuss the light objectively (the facts about the light itself), then I’ll discuss the light subjectively (my impressions about the light's performance when used for specific applications). If you have any other specific applications you'd like the light tested for, let me know and I'll see what I can do.

3-Minute Overview

Below is a video "quick review" you can watch in just a few minutes, if you're not up for reading the full review right now:

[video=youtube;CXrx_xiTDrM]https://www.youtube.com/watch?v=CXrx_xiTDrM[/video]
This video is available in 720p HD, but defaults to a lower quality. To select the playback quality click the settings button (looks like a gear) after you've started the video.


Objective

Manufacturer's Specifications

Price: $70




Packaging



The Cobra comes packaged and a cardboard box with various pictures and specifications printed on the front, back, and sides.



Inside, the Cobra sits in a plastic form mold, with the accessories stored in a bag underneath.


Construction




The Cobra is made from aluminum, coated in a black hard anodizing to resist chips and dents and scratches. The body of the light is slightly wider and a little longer than the single 18650 battery it is powered by.



The Cobra uses a single Cree XM-L emitter in a smooth reflector that is medium-sized for this class, so the overall effect is a beam that is nether a long-distance thrower nor a complete flood, but rather something just a little floodier than middle-of-the-road.



The Nitecore logo and product number and printed at the top of the head in clear white letters. Below that are the distinctive heat dissipation fins that lend the appearance of a cobra. Even with these fins is the stainless steal electronic button. This button is designed with a blue LED that shines through a clear circle around the button to act as an indicator (more about this indicator in the UI section).



The body and tail of the Cobra have Nitecore's characteristic spiral knurling pattern, to give the light a more grippable surface and to maintain the Nitecore style. The tail does not have a switch, it is completely flat.

Now, let's open it up!



In normal use, that Cobra comes apart into three sections: head, body, and tail.



Inside the head, you can see the metal circle that makes contact with the positive terminal of the batter. You can see that this terminal is surrounded by a black plastic ring--this ring is the mechanical reverse polarity protection feature of the Cobra. This means that because of this piece, a battery inserted backwards into the light should not be able to make electrical contact with the head (because it requires a slight protrusion to get past the ring and touch the post), thus preventing the battery from damaging the circuit. Also, as a side effect, this means that batteries with a flat top will likely not be able to make electrical contact with the head, and thus will not work in the Cobra without modification.

The threads are thick, square cut, and well greased, so their action is very smooth. On my review sample, the threads to the head are bare and the threads to the tail are anodized. This means that the light will continue to function if the head is loose, but loosening the tail will break the electrical circuit and prevent the light from activating. This is useful for a light with an electronic switch only, because it will prevent the circuit from drawing power when you are not using the light for a period of time.

Inside the tail is a metal spring to make connection with the negative battery terminal, which means the Cobra can accept a range of battery lengths, and the batteries will have some protection from damage in the event of an impact.



I use Callies Kustoms 18650's as my standard testing battery, and they just have a very slightly raised top that didn't quite make a solid connection because of the mechanical reverse polarity protection. As a temporary fix, I used a small spacer magnet (seen in the picture above), but I do not recommend using any sort of loose space regularly due to the risk of a short.



The Cobra is easily able to do a stable tail stand, because of the complete flatness of the tail.


Dimensions



Accessories



The Cobra comes with a holster, lanyard, clip-on-clip, and two spare o-rings.



As you can see, the clip can be attached facing either direction.



There is no lanyard hole built into the body, so the lanyard is attached to the clip.



The Cobra will fit into the holster either head up or head down.


User Interface

The Cobra uses a single electronic side switch that, like a camera shutter button, recognizes both a half press and a full press, to control a complex user interface that includes five brightness levels and two blinky modes.

First, the Cobra has a built-in mechanical lockout. When the tail cap is loose, the light is locked out and will not turn on with any button presses. When the tail cap is tightened, the light will no longer be locked out. When you first insert a battery an tighten the tail cap, the blue LED inside the ring around the button will start flashing to indicate the battery voltage. It gives the voltage in a pattern A.B Volts, by flashing first A flashes, then pausing, then flashing B flashes. So for example, if it flashes four times, pauses, then flashes two more times, your battery is at 4.2 V. Consequently, you can check the voltage of your battery at any time by loosening then tightening the tail cap and counting the flashes of the blue ring.

When the tail cap is fully tightened, you can then turn the light on. You have two options, either to give a full press or a half press to the side switch.

A half press will turn on one of the four regular brightness modes, Lowest -> Low -> Medium -> High, whichever you used last. If you hold the half press for about a second, the light will enter momentary mode and only remain lit in that brightness mode until you release the button. If you do the half press quickly, the light will enter constant mode and remain lit after you release. Once in one of these modes, a quick half press will advance you to the next mode in the sequence, a long half press will activate Turbo mode, or a full press will turn the light off.

When the light is off, a full press will take you straight to Turbo mode. If the full press is held for a second, it will be a momentary Turbo and the light will turn off again when you release the button. If it is a quick full press, the light will remain on until you give another quick full press.

At any time when the light is on, two quick full presses will activate Strobe mode, which is fast flashes of variable length at the same brightness as Turbo. When in Strobe, a half press will return you to the brightness level mode you came from, and a full press will turn the light off. Holding either a half or full press for about a second will activate the SOS mode.

Also at any time when the light is on a regular brightness mode, holding down a full press for about two seconds will activate the electronic lockout function, where the light will turn off, flash once, then not respond to any button presses until the button is held for about two seconds again. In electronic lockout, a very small amount of current will still be used (in contrast to mechanical lockout, which will use no current) to watch for the signal to turn back on.

At any time when the light is off but not locked out, the blue light in the ring around the button will give a quick locator flash once about every three seconds.

Action Shots

You can click on any of these shots to see them full size.

Light in Hand



White Wall (Very Low, Low, Medium, High, Turbo)
ISO 100, f/3.3, 1/20"



BeamSlice


MugShot


Indoor Shots (Very Low, Low, Medium, High, Turbo)
ISO 100, f/3.3, 1"



Outdoor Shots (Lowest, Low, Medium, High, Turbo)
ISO 100, f/3.3, 2.5"


Long Range (Turbo)
ISO 100, f/3.3, 5"



Performance

Submersion: I submersed the Cobra under about a foot of water for an hour, clicking the switch several times. I could find no evidence of water entering the light or causing damage.

Heat: On Turbo, the Cobra got very warm in about 25 minutes, but did not at any point get uncomfortable to hold.

PWM: I could find no evidence of pulse-width modulation on any mode.

Drop: I dropped the Cobra from a height of about 1 meter onto various surfaces (including grass, carpet, packed dirt, and wood). There was no functional damage or cosmetic damage evident.

Reverse Polarity Protection: The Cobra has mechanical reverse polarity protection, which means it also has some trouble with flat-top cells. See the Construction section for more details.

Over-Discharge Protection: While using the Cobra, the brightness will drop drastically from an otherwise steady output, then become very dim for a while when the battery voltage is low. Also, at any time you can check the voltage of the battery (accurate to 0.1V) by loosening then tightening the tail cap and counting the flashes of the ring around the button (see UI section for details).


Spectral Analysis


All light that we see as white is actually made up of several different colors put together. The relative intensities of the different colors in the mix are what determine the tint of the white we see. For example, cool white LED's have a lot of blue, and warm white LED's have more red or yellow. This measurement was done on a home made spectrometer. The plot below the picture is corrected for the spectral sensitivity of the human eye. Note: the peak in the 900nm region doesn't really exist, it's a piece of the second-order spectrum that's showing up here because of the high intensity of the light source.

Output and Runtime


ANSI FL-1 runtime ratings are the time it takes for a light to fall to 10% of it's original output (counting from 30 seconds after turning the light on).

The vertical axis of the graphs below represents a relative brightness measurement using a home made light box. The horizontal axis is time in hours:minutes:seconds. Runtimes are stated in hours:minutes:seconds. These graphs may be truncated to show detail.

Mode Comparison

Turbo

Truncated to show detail.

High

Truncated to show detail.

Medium

Truncated to show detail.


Throwing Distance

ANSI FL-1 standard for stating a light's throwing distance is the distance at which the peak beam intensity (usually at the center of the beam) is 0.25 lux. I calculate throwing distance and candela (lux at 1 meter) by measuring peak beam intensity at five different distances and using the formula lux*distance^2=constant.

Peak Beam Intensity: 21,302 cd
Throw Distance: 292m

Subjective Review

Quick break down:

+ Very high output
+ Compact
+ Many output levels available
+ Accurate voltage indicator
+ Looks cool with that blue light
+ Good find-your-flashlight beacon
+ Very good regulation, with a tail
+ Good heat management
+ Nitecore's style
+ Solid tail stand
+ Comfortable side switch
+ Mechanical lockout

- Complicated UI
- Batteries need a full button top

The EC25 Cobra is a very impressive light. My favorite aspect of the Cobra is it's great output:size ratio, and for that reason alone it's my go-to larger pocket light. Normally I carry something that runs from a single 16340 during the day, then switch to something 18650 sized at night. The Cobra isn't a super-compact 18650 light, because it's got a large reflector and substantial heat fins, but it is also brighter than most super-compacts, so it's often worth the extra space taken up to have that extra bit of throw and power. Much larger than the Cobra, and a light begins to be uncomfortable in my pocket and I start to want a holster.

My next favorite thing about the Cobra is the number of output levels available. Instead of the standard three levels, it's got five: Lowest, Low, Medium, High, Turbo. The lower four are well regulated, and Turbo is very bright for a short time before dropping to High. Plus, it's got the Strobe and SOS for the rare occasions I want it. The tradeoff here is that having so many options mean the UI is either going to be clunky or complicated. On the Cobra, the UI is intelligently designed so that you can quickly get to either Turbo or a lower mode with only a single press, but this means it's a little complicated and takes some time to learn and get comfortable with. At first, I would often find myself going to Turbo when I wanted Low because I wasn't used to only pressing the button halfway. So, the UI does take some time to get used to, but when you do it makes the light very easy to use and easy to get to the mode you want.

Also, I really like the looks and the style of the Cobra. because it's got Nitecore's distinctive style to it, right down to the spiral knurling pattern. I like the look of the heat fins, they are very good at both giving a visual impression and getting the job of heat dissipation done well. Also, I'm very impressed with the implementation of the voltage indicator light. More and more lights have voltage indication functions these days, but the Cobra has one that doesn't clutter either the UI or or aesthetic of the light. By putting it in that clear ring around the button, and designing the light to automatically display the voltage whenever the light starts up, Nitecore has promised not to waste space or time with the function. The voltage displayed is accurate, and easy to see, so that I often find myself routinely checking the voltage of the battery with a quick twist before dropping the light in my pocket and heading out the door.

One thing that I would change about the UI of the Cobra is the electronic lockout function of the user interface. Specifically, I would remove it. I understand the desire for this function in a light, especially one with only an electronic side switch for complete control. It makes sense to want to have a way to keep the light from accidentally turning on and to reduce power consumption when not in use. However, in the Cobra an electronic lockout is redundant and unnecessary clutter, because the Cobra already has a mechanical lockout. The threads of the Cobra are well made and well greased, so the tail loosens and tightens easily and smoothly. Using the mechanical lockout removes all power consumption and all chance of the light turning on accidentally. So, it's my logical preference to always use the mechanical lockout instead of the electronic lockout, but the electronic lockout is part of the UI, so there is a chance that I will sometimes activate it by accident, then go to use my light and have to remember what to do to turn my light back on. This is just my personal preference, so I will understand if some have other preferences, but for me the electronic lockout just gets in the way.

Overall, the Cobra is an excellent high powered compact 18650 light. There are some that are smaller, and some that have more power, but the Cobra is the best combo of small size and high output that I have reviewed so far: over 800 lumens, but still small enough to fit in a pocket comfortably. I this is what you're looking for, the Cobra has it, with a good sophisticated UI thrown in.


Long Term Impressions
I'll fill this part in after carrying the light for a while. If nothing get's added here, either I find nothing else worth noting about the light, or I end up not using it often.