Introduction
This light was provided free of charge by Nitecore Store for review. It shipped from their location in Texas.
https://www.nitecorestore.com/Nitecore-Concept-1-p/fl-nite-c1.htm
The Concept 1, or C1, is the first and only light in the new Concept line from Nitecore. It is a departure from the familiar looks of other Nitecore lights, taking on a more modern and sleek design. The switch is a metal side switch, the tube is minimalist, and the pocket clip is attached with allen screws as used by many custom-made lights.
The Concept 1 features a Cree XHP35 HD E2 emitter and advertises maximum output of 1800 lumens when used with a high drain IMR18650 battery. The UI is very unique and a lockout at the tail cap should be performed when the C1 is not in use.
Here are the key review details in one table for the TL;DR crowd:
Packaging
The Concept 1 arrived in a retail box within a padded envelope. The Concept 1's retail box is a departure from the usual Nitecore design, now being a sleek flat black box with minimal pictures and writing. It's almost as if a certain company from Cupertino designed it.
Viewing the C1's box next to the packaging for the EC4SW (late 2015) and SRT7GT (2017), the difference is quite obvious.
The front has a glossy image of the Concept 1 along with the 1800 lumen claim, Concept 1 designation, and the Nitecore logo. Nothing more.
The back has the model name, the specifications, a two-line description of the Concept 1, and basic registration and safety information in white on the black background. Both sides are identical and only declare "Concept Series" in yellow.
A small piece of paper was sticking out of the top of the box. This piece of paper is a Quick Start Guide likely added by Nitecore Store to help new users. The UI of the C1 is very unique – and it appears Nitecore Store wanted to make sure users understood it and the need to lock the C1 out when not in use. (More on the UI further below.)
Opening the box, we find the C1 in a plastic carrier with the accessories underneath.
Included is a holster, manual, warranty card, spare o-rings, Nitecore product line pamphlet, lanyard, and pocket clip (attached to C1).
The manual is in 9 languages (English, Spanish, German, French, Polish, Japanese, Romanian, Chinese, and I believe Korean); each language's section is complete as the text is quite small.
It can be accessed online here:
http://flashlight.nitecore.com/pdf/C1_UM_EN.pdf
The Quick Start Guide simplifies the manual quite a bit.
Design
The Concept 1 is the most compact single 18650 light I've handled. Everything about it is clean and compact. The knurling is minimal and mild. The switch is moved to the outside to keep the tube tidy. The bezel is flat and simple. No ounces spared.
I measured the overall length at 111.5mm and head diameter at 24 mm. Weight was tested without battery at 62 g.
The C1's compact size is evident when put next to other lights. Even the Convoy S2+ and Manker E14 II are longer or wider, and heavier by 8 and 32 grams, respectively.
In this image, the C1 is in center.
Left to right: Nitecore EC4SW (dual 18650), Nitecore SRT7GT (single 18650), Convoy S2+ (single 18650), Nitecore C1 (single 18650), Manker E14 II (single 18650), ThorFire C8S (single 18650), Olight R50 Pro (single 26650).
The head has all of the writing: Nitecore logo, website, model name, registration, and disposal information. The embossing is clear and easy to read.
The battery tube's knurling is only towards the tail end of the light. It adds useful grip but overall is quite mild.
Just to the side of that embossing is the only other printing on the C1: The HOT logo.
The Concept 1's unique switch is a rocker-style metal switch on the side of the head, close to the bezel. It has 3 small raised lines on it to add some feel. A phillips head screw goes through the switch into the body; the switch has a tiny amount of side-to-side play as the screw head has a small amount of space around it.
From the side, the way the switch functions is visible. The screw holds the switch to the light while a small pin further up the switch activates the tiny button underneath. When the switch is pressed, the screw does not move – the switch moves using the screw as a guide.
The bezel of the C1 is flat. When the C1 is placed head-down on a flat surface, no light can escape. So, the user must be careful to make sure the light is off before setting down this way to avoid draining the battery or damaging the surface.
The glass is AR-coated. The reflector is smooth and free of imperfections.
The Cree XHP35 HD E2 LED is perfectly centered.
The tail of the light is also flat and simple. It tailstands well. A magnet in the tail is strong enough to hold the C1 in place on sturdy and still objects (such as a refrigerator) but is too weak to hold keep the C1 in place when movement is present (such as in a moving vehicle).
The Concept 1 disassembles into 3 sections: head, body tube, and tail.
The head of the C1 has a raised positive terminal. It is compatible with flat and button top batteries.
The threads on the head end are square cut and very well lubricated.
The tail cap has a gold-colored spring. It is firm but was flexible enough to work with various protected and unprotected batteries I tested.
The tail threads are also square cut and well lubricated.
Both ends have o-rings for water ingress protection and Nitecore presents the light as having IPX-8 water resistance to 2 meters underwater. The C1 is also impact resistant to 1.5 meters.
The black pocket clip is attached with two allen screws. The design is simple and functional,and there are no bends or protrusions that'd hang up on clothing. The strength was a good balance - strong enough to keep the C1 in place on the brim of a hat but not so strong it requires two hands.
The included lanyard can attach via the hole in the pocket clip. It could also be attached to the switch as the screw through the switch would keep it from sliding off, but that doesn't seem very practical. I expect few C1 owners to use the lanyard as there's no nice way of attaching it,though the quality of the lanyard is good.
The holster fits the C1 well whether the C1 is stored head up or head down. It has a D-ring, belt pass-through loop, and hook-and-loop strap – offering useful flexibility. The bottom of the holster is closed so it is imperative that the C1 be locked out by loosening the tailcap before holstering the C1. The switch will get bumped in the holster, turning the C1 on if not locked out.
Performance
The smooth reflector produces a defined hotspot and corona surrounded by the spill. There are some rings within the beam due to the reflection off the bezel, though these are only noticeable indoors.
The color of the beam is a creamy neutral in the center but with a cooler blue in the spill. Where the two transition some green is present – though not very noticeable in real-world use due the brightness of the hotspot.
To demonstrate the relative color balance, here is the C1 flanked by lights with emitters of various tints and temperatures.
L to R: Olight S1R with cool XM-L2, Astrolux S41S with neutral 219B, Nitecore EC4SW with neutral MT-G2, Nitecore C1 with cool XHP35 HD, Convoy S2+ with cool XM-L U2 1B, BLF348 with neutral 219B, and Lumintop Tool with warm 219B.
I found the tint to be similar to that found in cool XM-L emitters in other lights.
L to R: Convoy S2+ with cool XM-L U2 1B, Nitecore C1 with XHP35 HD, ThorFire VG-15S with cool XL-L2, and Astrolux S41S with neutral 219B (for reference).
Nitecore rates the Concept 1 at 1800 lumens on Turbo when used with an 18650 battery capable of output current greater than 8A. The recommended IMR18650 3100mAh Nitecore battery is rated to sustain 10A.
2xCR123A batteries can be used with the C1 but Turbo will not be accessible. If an 18650 incapable of sustaining 8A (as is the case with most protected cells) is used, the C1 will shut off immediately on Turbo and require the tail cap to be loosened to reset the circuit.
The Concept 1 also has Nitecore's "Advanced Temperature Regulation module", designed to keep the LED from overheating.
What I found in Turbo testing is that the C1's ATR system was VERY active. At turn-on, the C1 output an impressive 2007 lumens with the Nitecore IMR18650 3100mAh 10A battery. But in just a few seconds, the ATR started to adjust the output.
I tested multiple times with the Concept 1 at various starting temperatures and both with and without a cooling fan. At the 30 second mark, the output varied between 979 and 1444 lumens using the Nitecore 10A IMR cell.
The test that produced 979 was with a hot light (previously on turbo), stationary, with no cooling. The test that produced 1444 lumens was performed with the C1 straight out of a freezer. Neither of these are typical testing scenarios and were excluded from the numbers reported below, but the disparity shows that the C1 is very susceptible to its own temperature and the ambient temperature. In most tests, the output was around 1350 lumens with 1372 being the result I reported on Turbo.
Nitecore rates Turbo at 1800 lumens and in some of my tests it held output at or above this level as long as 25 seconds – almost to the 30 second ANSI test standard. With the right scenario it could be possible, but whether 25 or 35 seconds, users should expect Turbo to truly be a short burst mode only.
Also interesting is in that the ATR can both increase and decrease the output. In a "hot" test, I added a 80mm PC cooling fan after the light stepped down and saw the output go back up a fair amount.
From about 2000 lumens at turn on, the C1 dropped about 50 lumens in the first 15 seconds. Between 25 and 30 seconds the output dropped down to about 1320 lumens. It then leveled off at about 1.5 minutes into the test.
A gradual decline ensued through minute 92 when the C1 was down to 630 lumens. Three big step-downs occurred between minute 92 and minute 105; the light then held on at 2 lumens until minute 169 (2:49).
Nitecore states that Turbo should run for 30 minutes (0:30) "calculated based on theoretical arithmetic." In reality, I found it took 92 minutes (1:32) to reach 50% output and 95 minutes (1:35) to reach 10% (ANSI runtime), exceeding Nitecore's calculated figure.
The test was conducted using a 10A IMR18650 3100mAh cell since that's what was listed as the battery used in the official runtime rating. I had an 80mm PC fan running to produce some airflow. Ambient temp was 78F.
An unprotected LG HG2 cell produced a statistically similar output.
The external temperature of the C1 never got uncomfortably hot to hold. With a single Turbo activation, indoors at 78F with no added cooling, the light topped out at 107F (41.6C). If I repeatedly activated Turbo, it climbed to as high as 122F (50C).
Nitecore rates High at 810 lumens. I found 979 at 30 seconds in my testing. It held 950 lumens through 2.5 minutes before beginning a decline that would see it level off at 820 lumens at minute 7. From there the C1 held a fairly consistent output declining only to 685 lumens by minute 93. In the 12 minutes that followed from there, three significant step-downs occurred.
Nitecore states that High should run for 90 minutes also "calculated based on theoretical arithmetic." In reality, I found it took 95 minutes to reach 50% output and 98 minutes to reach 10% (ANSI runtime). Nitecore's calculated rating is spot-on.
Medium is rated at 300 lumens. I found 351 in my testing with multiple tests producing quite consistent results (+/- 5 lumens). The output on Medium was also very well regulated; from 351 lumens at 30 seconds it maintained no less than 347 lumens through 4 hours and 6 minutes. It was at that point that output stepped below 50% to 89 lumens. At 4 hours and 12 minutes, the C1 dropped below 10% of its initial output. A runtime of 4 hours and 12 minutes is in line with Nitecore's own 4 hour rating.
Nitecore rates Low at 80 lumens; I tested it at a close 83. Runtimes were not tested.
Finally, Nitecore rates Ultralow at 1 lumen. I found it to produce 2 lumens. Runtimes were not tested.
All outputs as tested:
All runtimes tested:
Note that Turbo and High follow a very similar curve after the first 5 minutes or so.
I tested throw distance at 1.46 meters and the resulting candela was 10,317 - equivalent to 203 meters of throw. Nitecore rates the C1 at 220 meters of throw. While my result was 17 meters off, I do not consider this difference significant as environmental and test variables will cause deviation especially given the short window the C1 maintains peak turbo output.
I did not detect PWM on any modes using cameras or the "mirror test". Nitecore advertises the C1 is PWM-free, using "constant circuit".
The battery measured between 2.88 and 2.93V after all tests. The over-discharge protection is good as this is a safe termination voltage!
Outdoor Beamshots
All photos taken with a Canon SD4000IS camera. 1/4" exposure, ISO800, Daylight white balance.
Approximate distances: White deck railing @ 15 ft., white fence in distance @ 75 ft., center of boat @ 100 ft.
Control shot:
Low:
Med:
High:
Turbo:
[Due to the hot summer temperature, Turbo had stepped down slightly when the image was captured. I didn't realize this initially; I'll be attempting a re-take.]
Interface
The Concept 1 uses a very unique interface.
To start, it has General and Tactical modes. General is the default selection and will likely be the favorite of most owners.
From off, a single quick press of the side switch does nothing.
From off, a long press returns to the last used mode (mode memory).
From off, a press and hold returns to the last mode used and begins to cycle upward. When released, the C1 will remain on that mode.
From off, a double press turns on Ultralow.
From off, a triple press turns on Turbo.***
While on, a single press turns the C1 off.
While on, a press and hold activates momentary Turbo. It returns to the previous mode when released.
While on, a triple press turns on Strobe. Press and hold cycles through SOS and Beacon modes Strobe from there.
***If Tactical mode is activated (disabling General mode) by holding the side switch while tightening the tailcap, triple press from off goes to Strobe instead of Turbo. Even in Tactical mode, holding the switch while the C1 is on will activate momentary turbo.
One advantage of this complex UI is that the light can turn on in Ultralow, Turbo, or the mode last used. Another is that momentary turbo can be accessed at any time without the need for an additional switch like found on the TM03.
The notable disadvantage is that the C1, with its external and easily-pressed switch, will turn on in a pocket or holster if not locked out. The mechanical lockout (by unscrewing the tail cap slightly) MUST be used. Nitecore communicates this in the manual with "When the product is not in use, it is advised to loosen the tail cap to prevent accidental activation." The Quick Start Guide that Nitecore Store included states "To prevent accidental activation, loosen the tail cap ¼ turn when not in use."
When the tail cap is tightened, the C1 will display battery voltage by flashing the LED. If the battery is 3.8 volts, for example, the LED will give 3 blinks, pause, then flash 8 times more. I did notice it indicates 4.1V when a battery is fresh off a charger though I expected to see 4.2.
Pressing the switch while the C1 is flashing the voltage will stop the voltage check and turn the C1 on.
Problems
No problems were experienced while testing the C1.
Commentary
This light is unlike any other mass-produced light. It seems to take many design cues from custom builders. Sleek. Minimalist. Classy. No other 18650-based lights that I own are this compact or can match the C1's balance of output and weight.
It is a bit annoying having to turn the light off before being able to cycle between modes once already in use, though the momentary access to Turbo makes up for it to me. Hold the button, get Turbo, release, and you're back to where you were. As ATR steps Turbo down fairly quickly anyway, this momentary burst is the way I'd expect most users to use Turbo.
I also appreciate that the C1 is compatible with button or flat top cells – something not common with all Nitecore lights. The C1 can use most high drain unprotected cells that owners may have like LG HG2, Samsung 30Q, or Sony VTC5A. The optional Nitecore IMR18650 10A performs very well for those that prefer to go with the OEM-recommended battery.
The lumen count is quite good. Turn-on output north of 2000 lumens is a pleasant surprise though the fall-off due to the heat is very fast. The heatsinking does not sustain the output as long as the Manker E14II or Nitecore TM03, but the C1 remains much more comfortable to hold while retaining the small form factor and light weight. It's a reasonable trade-off, but those who need long Turbo performance will need to seek larger lights.
The XHP35 HD's cool tint might not agree with everyone, yet the beam itself has a very practical balance of flood and throw that makes it a good general purpose or EDC light.
It's also good to have options with the pocket clip, lanyard, holster, magnetic tail, and spare o-rings included – though lanyard attachment is a bit awkward.
Overall the C1 is a classy looking, comfortable to carry compact light with a lot of power for short duration Turbo use. The unique UI and need to lock out at the tail when not in use will likely be the deciding factors for most potential buyers.
Nitecore backs the Concept 1 with a 5 year warranty.
As a final note I cannot stress enough: Users should perform a tail cap lockout whenever the light is not in use. Whether in a pocket, in the holster, or just on a shelf where children can reach, locking out the C1 is critical. I own several other lights that I lock out whenever I pocket but none have as sensitive of a switch as the C1. During testing I put it in the holster without it locked out once by accident and found the holster literally smoking shortly after. Always lock out the C1 when not in use!
Meter: Dr. Meter LX1330B
Integrating "sphere": Homebuilt tube-style device calibrated on other known lights and test results. Numbers should be considered relative to each other and my other review figures but accuracy is in no way certified or guaranteed.
Camera: Canon SD4000IS
This light was provided free of charge by Nitecore Store for review. It shipped from their location in Texas.
https://www.nitecorestore.com/Nitecore-Concept-1-p/fl-nite-c1.htm
The Concept 1, or C1, is the first and only light in the new Concept line from Nitecore. It is a departure from the familiar looks of other Nitecore lights, taking on a more modern and sleek design. The switch is a metal side switch, the tube is minimalist, and the pocket clip is attached with allen screws as used by many custom-made lights.
The Concept 1 features a Cree XHP35 HD E2 emitter and advertises maximum output of 1800 lumens when used with a high drain IMR18650 battery. The UI is very unique and a lockout at the tail cap should be performed when the C1 is not in use.
Here are the key review details in one table for the TL;DR crowd:
Packaging
The Concept 1 arrived in a retail box within a padded envelope. The Concept 1's retail box is a departure from the usual Nitecore design, now being a sleek flat black box with minimal pictures and writing. It's almost as if a certain company from Cupertino designed it.
Viewing the C1's box next to the packaging for the EC4SW (late 2015) and SRT7GT (2017), the difference is quite obvious.
The front has a glossy image of the Concept 1 along with the 1800 lumen claim, Concept 1 designation, and the Nitecore logo. Nothing more.
The back has the model name, the specifications, a two-line description of the Concept 1, and basic registration and safety information in white on the black background. Both sides are identical and only declare "Concept Series" in yellow.
A small piece of paper was sticking out of the top of the box. This piece of paper is a Quick Start Guide likely added by Nitecore Store to help new users. The UI of the C1 is very unique – and it appears Nitecore Store wanted to make sure users understood it and the need to lock the C1 out when not in use. (More on the UI further below.)
Opening the box, we find the C1 in a plastic carrier with the accessories underneath.
Included is a holster, manual, warranty card, spare o-rings, Nitecore product line pamphlet, lanyard, and pocket clip (attached to C1).
The manual is in 9 languages (English, Spanish, German, French, Polish, Japanese, Romanian, Chinese, and I believe Korean); each language's section is complete as the text is quite small.
It can be accessed online here:
http://flashlight.nitecore.com/pdf/C1_UM_EN.pdf
The Quick Start Guide simplifies the manual quite a bit.
Design
The Concept 1 is the most compact single 18650 light I've handled. Everything about it is clean and compact. The knurling is minimal and mild. The switch is moved to the outside to keep the tube tidy. The bezel is flat and simple. No ounces spared.
I measured the overall length at 111.5mm and head diameter at 24 mm. Weight was tested without battery at 62 g.
The C1's compact size is evident when put next to other lights. Even the Convoy S2+ and Manker E14 II are longer or wider, and heavier by 8 and 32 grams, respectively.
In this image, the C1 is in center.
Left to right: Nitecore EC4SW (dual 18650), Nitecore SRT7GT (single 18650), Convoy S2+ (single 18650), Nitecore C1 (single 18650), Manker E14 II (single 18650), ThorFire C8S (single 18650), Olight R50 Pro (single 26650).
The head has all of the writing: Nitecore logo, website, model name, registration, and disposal information. The embossing is clear and easy to read.
The battery tube's knurling is only towards the tail end of the light. It adds useful grip but overall is quite mild.
Just to the side of that embossing is the only other printing on the C1: The HOT logo.
The Concept 1's unique switch is a rocker-style metal switch on the side of the head, close to the bezel. It has 3 small raised lines on it to add some feel. A phillips head screw goes through the switch into the body; the switch has a tiny amount of side-to-side play as the screw head has a small amount of space around it.
From the side, the way the switch functions is visible. The screw holds the switch to the light while a small pin further up the switch activates the tiny button underneath. When the switch is pressed, the screw does not move – the switch moves using the screw as a guide.
The bezel of the C1 is flat. When the C1 is placed head-down on a flat surface, no light can escape. So, the user must be careful to make sure the light is off before setting down this way to avoid draining the battery or damaging the surface.
The glass is AR-coated. The reflector is smooth and free of imperfections.
The Cree XHP35 HD E2 LED is perfectly centered.
The tail of the light is also flat and simple. It tailstands well. A magnet in the tail is strong enough to hold the C1 in place on sturdy and still objects (such as a refrigerator) but is too weak to hold keep the C1 in place when movement is present (such as in a moving vehicle).
The Concept 1 disassembles into 3 sections: head, body tube, and tail.
The head of the C1 has a raised positive terminal. It is compatible with flat and button top batteries.
The threads on the head end are square cut and very well lubricated.
The tail cap has a gold-colored spring. It is firm but was flexible enough to work with various protected and unprotected batteries I tested.
The tail threads are also square cut and well lubricated.
Both ends have o-rings for water ingress protection and Nitecore presents the light as having IPX-8 water resistance to 2 meters underwater. The C1 is also impact resistant to 1.5 meters.
The black pocket clip is attached with two allen screws. The design is simple and functional,and there are no bends or protrusions that'd hang up on clothing. The strength was a good balance - strong enough to keep the C1 in place on the brim of a hat but not so strong it requires two hands.
The included lanyard can attach via the hole in the pocket clip. It could also be attached to the switch as the screw through the switch would keep it from sliding off, but that doesn't seem very practical. I expect few C1 owners to use the lanyard as there's no nice way of attaching it,though the quality of the lanyard is good.
The holster fits the C1 well whether the C1 is stored head up or head down. It has a D-ring, belt pass-through loop, and hook-and-loop strap – offering useful flexibility. The bottom of the holster is closed so it is imperative that the C1 be locked out by loosening the tailcap before holstering the C1. The switch will get bumped in the holster, turning the C1 on if not locked out.
Performance
The smooth reflector produces a defined hotspot and corona surrounded by the spill. There are some rings within the beam due to the reflection off the bezel, though these are only noticeable indoors.
The color of the beam is a creamy neutral in the center but with a cooler blue in the spill. Where the two transition some green is present – though not very noticeable in real-world use due the brightness of the hotspot.
To demonstrate the relative color balance, here is the C1 flanked by lights with emitters of various tints and temperatures.
L to R: Olight S1R with cool XM-L2, Astrolux S41S with neutral 219B, Nitecore EC4SW with neutral MT-G2, Nitecore C1 with cool XHP35 HD, Convoy S2+ with cool XM-L U2 1B, BLF348 with neutral 219B, and Lumintop Tool with warm 219B.
I found the tint to be similar to that found in cool XM-L emitters in other lights.
L to R: Convoy S2+ with cool XM-L U2 1B, Nitecore C1 with XHP35 HD, ThorFire VG-15S with cool XL-L2, and Astrolux S41S with neutral 219B (for reference).
Nitecore rates the Concept 1 at 1800 lumens on Turbo when used with an 18650 battery capable of output current greater than 8A. The recommended IMR18650 3100mAh Nitecore battery is rated to sustain 10A.
2xCR123A batteries can be used with the C1 but Turbo will not be accessible. If an 18650 incapable of sustaining 8A (as is the case with most protected cells) is used, the C1 will shut off immediately on Turbo and require the tail cap to be loosened to reset the circuit.
The Concept 1 also has Nitecore's "Advanced Temperature Regulation module", designed to keep the LED from overheating.
What I found in Turbo testing is that the C1's ATR system was VERY active. At turn-on, the C1 output an impressive 2007 lumens with the Nitecore IMR18650 3100mAh 10A battery. But in just a few seconds, the ATR started to adjust the output.
I tested multiple times with the Concept 1 at various starting temperatures and both with and without a cooling fan. At the 30 second mark, the output varied between 979 and 1444 lumens using the Nitecore 10A IMR cell.
The test that produced 979 was with a hot light (previously on turbo), stationary, with no cooling. The test that produced 1444 lumens was performed with the C1 straight out of a freezer. Neither of these are typical testing scenarios and were excluded from the numbers reported below, but the disparity shows that the C1 is very susceptible to its own temperature and the ambient temperature. In most tests, the output was around 1350 lumens with 1372 being the result I reported on Turbo.
Nitecore rates Turbo at 1800 lumens and in some of my tests it held output at or above this level as long as 25 seconds – almost to the 30 second ANSI test standard. With the right scenario it could be possible, but whether 25 or 35 seconds, users should expect Turbo to truly be a short burst mode only.
Also interesting is in that the ATR can both increase and decrease the output. In a "hot" test, I added a 80mm PC cooling fan after the light stepped down and saw the output go back up a fair amount.
From about 2000 lumens at turn on, the C1 dropped about 50 lumens in the first 15 seconds. Between 25 and 30 seconds the output dropped down to about 1320 lumens. It then leveled off at about 1.5 minutes into the test.
A gradual decline ensued through minute 92 when the C1 was down to 630 lumens. Three big step-downs occurred between minute 92 and minute 105; the light then held on at 2 lumens until minute 169 (2:49).
Nitecore states that Turbo should run for 30 minutes (0:30) "calculated based on theoretical arithmetic." In reality, I found it took 92 minutes (1:32) to reach 50% output and 95 minutes (1:35) to reach 10% (ANSI runtime), exceeding Nitecore's calculated figure.
The test was conducted using a 10A IMR18650 3100mAh cell since that's what was listed as the battery used in the official runtime rating. I had an 80mm PC fan running to produce some airflow. Ambient temp was 78F.
An unprotected LG HG2 cell produced a statistically similar output.
The external temperature of the C1 never got uncomfortably hot to hold. With a single Turbo activation, indoors at 78F with no added cooling, the light topped out at 107F (41.6C). If I repeatedly activated Turbo, it climbed to as high as 122F (50C).
Nitecore rates High at 810 lumens. I found 979 at 30 seconds in my testing. It held 950 lumens through 2.5 minutes before beginning a decline that would see it level off at 820 lumens at minute 7. From there the C1 held a fairly consistent output declining only to 685 lumens by minute 93. In the 12 minutes that followed from there, three significant step-downs occurred.
Nitecore states that High should run for 90 minutes also "calculated based on theoretical arithmetic." In reality, I found it took 95 minutes to reach 50% output and 98 minutes to reach 10% (ANSI runtime). Nitecore's calculated rating is spot-on.
Medium is rated at 300 lumens. I found 351 in my testing with multiple tests producing quite consistent results (+/- 5 lumens). The output on Medium was also very well regulated; from 351 lumens at 30 seconds it maintained no less than 347 lumens through 4 hours and 6 minutes. It was at that point that output stepped below 50% to 89 lumens. At 4 hours and 12 minutes, the C1 dropped below 10% of its initial output. A runtime of 4 hours and 12 minutes is in line with Nitecore's own 4 hour rating.
Nitecore rates Low at 80 lumens; I tested it at a close 83. Runtimes were not tested.
Finally, Nitecore rates Ultralow at 1 lumen. I found it to produce 2 lumens. Runtimes were not tested.
All outputs as tested:
All runtimes tested:
I tested throw distance at 1.46 meters and the resulting candela was 10,317 - equivalent to 203 meters of throw. Nitecore rates the C1 at 220 meters of throw. While my result was 17 meters off, I do not consider this difference significant as environmental and test variables will cause deviation especially given the short window the C1 maintains peak turbo output.
I did not detect PWM on any modes using cameras or the "mirror test". Nitecore advertises the C1 is PWM-free, using "constant circuit".
The battery measured between 2.88 and 2.93V after all tests. The over-discharge protection is good as this is a safe termination voltage!
Outdoor Beamshots
All photos taken with a Canon SD4000IS camera. 1/4" exposure, ISO800, Daylight white balance.
Approximate distances: White deck railing @ 15 ft., white fence in distance @ 75 ft., center of boat @ 100 ft.
Control shot:
Low:
Med:
High:
Turbo:
[Due to the hot summer temperature, Turbo had stepped down slightly when the image was captured. I didn't realize this initially; I'll be attempting a re-take.]
Interface
The Concept 1 uses a very unique interface.
To start, it has General and Tactical modes. General is the default selection and will likely be the favorite of most owners.
From off, a single quick press of the side switch does nothing.
From off, a long press returns to the last used mode (mode memory).
From off, a press and hold returns to the last mode used and begins to cycle upward. When released, the C1 will remain on that mode.
From off, a double press turns on Ultralow.
From off, a triple press turns on Turbo.***
While on, a single press turns the C1 off.
While on, a press and hold activates momentary Turbo. It returns to the previous mode when released.
While on, a triple press turns on Strobe. Press and hold cycles through SOS and Beacon modes Strobe from there.
***If Tactical mode is activated (disabling General mode) by holding the side switch while tightening the tailcap, triple press from off goes to Strobe instead of Turbo. Even in Tactical mode, holding the switch while the C1 is on will activate momentary turbo.
One advantage of this complex UI is that the light can turn on in Ultralow, Turbo, or the mode last used. Another is that momentary turbo can be accessed at any time without the need for an additional switch like found on the TM03.
The notable disadvantage is that the C1, with its external and easily-pressed switch, will turn on in a pocket or holster if not locked out. The mechanical lockout (by unscrewing the tail cap slightly) MUST be used. Nitecore communicates this in the manual with "When the product is not in use, it is advised to loosen the tail cap to prevent accidental activation." The Quick Start Guide that Nitecore Store included states "To prevent accidental activation, loosen the tail cap ¼ turn when not in use."
When the tail cap is tightened, the C1 will display battery voltage by flashing the LED. If the battery is 3.8 volts, for example, the LED will give 3 blinks, pause, then flash 8 times more. I did notice it indicates 4.1V when a battery is fresh off a charger though I expected to see 4.2.
Pressing the switch while the C1 is flashing the voltage will stop the voltage check and turn the C1 on.
Problems
No problems were experienced while testing the C1.
Commentary
This light is unlike any other mass-produced light. It seems to take many design cues from custom builders. Sleek. Minimalist. Classy. No other 18650-based lights that I own are this compact or can match the C1's balance of output and weight.
It is a bit annoying having to turn the light off before being able to cycle between modes once already in use, though the momentary access to Turbo makes up for it to me. Hold the button, get Turbo, release, and you're back to where you were. As ATR steps Turbo down fairly quickly anyway, this momentary burst is the way I'd expect most users to use Turbo.
I also appreciate that the C1 is compatible with button or flat top cells – something not common with all Nitecore lights. The C1 can use most high drain unprotected cells that owners may have like LG HG2, Samsung 30Q, or Sony VTC5A. The optional Nitecore IMR18650 10A performs very well for those that prefer to go with the OEM-recommended battery.
The lumen count is quite good. Turn-on output north of 2000 lumens is a pleasant surprise though the fall-off due to the heat is very fast. The heatsinking does not sustain the output as long as the Manker E14II or Nitecore TM03, but the C1 remains much more comfortable to hold while retaining the small form factor and light weight. It's a reasonable trade-off, but those who need long Turbo performance will need to seek larger lights.
The XHP35 HD's cool tint might not agree with everyone, yet the beam itself has a very practical balance of flood and throw that makes it a good general purpose or EDC light.
It's also good to have options with the pocket clip, lanyard, holster, magnetic tail, and spare o-rings included – though lanyard attachment is a bit awkward.
Overall the C1 is a classy looking, comfortable to carry compact light with a lot of power for short duration Turbo use. The unique UI and need to lock out at the tail when not in use will likely be the deciding factors for most potential buyers.
Nitecore backs the Concept 1 with a 5 year warranty.
As a final note I cannot stress enough: Users should perform a tail cap lockout whenever the light is not in use. Whether in a pocket, in the holster, or just on a shelf where children can reach, locking out the C1 is critical. I own several other lights that I lock out whenever I pocket but none have as sensitive of a switch as the C1. During testing I put it in the holster without it locked out once by accident and found the holster literally smoking shortly after. Always lock out the C1 when not in use!
Meter: Dr. Meter LX1330B
Integrating "sphere": Homebuilt tube-style device calibrated on other known lights and test results. Numbers should be considered relative to each other and my other review figures but accuracy is in no way certified or guaranteed.
Camera: Canon SD4000IS
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