Thursday, September 14, 2017

Nitecore SRT9 Review Multi-color LED tactical flashlight

Nitecore SRT9 is a dual 18650 powered flashlight from Nitecore's tactical series flashlights.
It shares the idea of the successful SRT7 model,which was popular with its additional color LEDs and also with its good main beam range.
Nitecore sent me for test their SRT9 flashlight and I had the chance to test it for quite long time,before posting the review.
Read the review below for my impressions and findings.

Nitecore SRT9 has a die-cast produced body very similar to the popular EC4/S model.Elliptical profile battery tube with two 18650 batteries side by side(electrically connected in series).
There are quite a lot differences in the new flashlight though. As a tactical flashlight SRT9 features rear switch with momentary On option.
Selecting the modes is possible by a magnetic smart ring,which is responsible for adjusting the output of the main white beam,activating the flashing modes,
activating the Red/Green/Blue/UV light and leaving the flashlight in Standby mode,ready for use just by the smart ring-with no need of changing the grip.

The tail switch requires redesigning the tailcap and the SRT9 comes with a new interesting method for locking/unlocking it.Read more for this later in the review.

Here is a comparison with other Nitecore flashlights-EC4S,MH27,P30.
You can notice on the pictures that the finish of the SRT9 is not as matte as this on the EC4S.
Nitecore SRT9 324gr.
Nitecore EC4S 275gr.

The SRT9 is designed to allow tail-standing.However in my attempts,I can't come to a reasonable,stable standing even on a flat surface.
Just a light vibration and the flashlight falls.
The SRT9 does not feature tactical bezel as the MH27.

Important to mention is the pocket clip,which even though not perfect will add more options to carry the flashlight without holster.

Cool white Cree XHP50 LED,orange peel reflector(no difference with the EC4S).
Different is the type of texture and the addition of holes for the color 5mm LEDs.
The 40mm head diameter is standard for Nitecore and allows you to attach the filters/diffusers you already use with previous models like EC4S,MH27,etc.

Here is a close look at the forward clicky switch and its N marked cap.
All edges around the switch are very well rounded,which is bad for tail-stand capability,but pressing the switch is easy and comfortable.

Here is a close look at the magnetic smart ring.
Again,here we can see that all edges of the cooling fins and the grooves of the battery tube are very well rounded.
The smart ring has many defined stops,easy to feel when rotating it.
Unfortunately there is no any marking and the only way to know which mode is currently selected is to remember the whole mode sequence and when needed(in Off state) to rotate the ring far right or left,
then count the clicks. I usually rotate it until white light,which is easy to define because of its gradual adjustment with no stops.

A look at the battery tube.

I got two Nitecore 3200mAh batteries with the review flashlight.
Unexpectedly the screws holding the tailcap board keep the battery away from the + point and I did not managed to use these batteries in the SRT9.
Dual coil springs for better current flaw.

Close up view of the locking pin.

The tailcap can be detached after pressing each of the two pins until unlocking sound is heard.
To close the tailcap,just press it toward the battery tube.Depending on the battery size,this may take a lot of force.
To keep everything well sealed and tight,be sure the buttons are back to their initial position-fully released.

Below is a runtime graph that represents how the brightness is changing after activation on max output.
The SRT9 features advanced thermal regulation,which should ensure safe working temperature in use.
I started the test without additional cooling and activated a small cooling fan 10 minutes later.
Nitecore SRT9 reaches about 2000 lumens and as expected at this output the whole flashlight gets hot after a few minutes.
I am happy to report that the ATR here works as expected and we can see its work easy on the graph.
At certain temperature the brightness is automatically decreased to a little less than 1200 lumens.
The max output possible depending on the current battery state is again reached after lowering the temperature.
In my test,this is 3 minutes after activating the cooling fan.
The batteries that I used did not manage to keep the output constant and the output after recovering the maximum possible brightness dropped proportionally to the battery voltage.

1920Lm initial output,1820Lm after 30sec(Keeppower 3400 batteries)

Here is a graph with only the first 30 minutes for a better view of the curve.

-While in StandBy mode,the SRT9 will draw a small current from the battery.I did not manage to measure it yet,though and can't confirm its value.
As usual with most electronic switches-it is recommended to turn the tail switch Off when the light will not be used for more than a week.

Close up of the laser engraving.

View at the textured reflector and the five LEDs.

The central Cree XHP50 LED is well centered.
We can see the shape of the holes for the 5mm color LEDs.

This is a reflector comparison with Nitecore EC4S,which shares the same LED.
The type of the texture is different,as well as the hole for the XHP50 LED.
Similar matte grey front bezels.

Beam profile

As expected the 5mm Red,Green,Blue LEDs combined with a reflective surface around them,result in different asymmetric shape beams.
This is usually the price of having additional color lights in a standard flashlight.
Normally,the color beams do the job quite well.They are just not meant for homogeneous illumination of wide areas.
They are meant for checking different objects without much requirements of the artifacts.
A diffuser for smoothing the beam is always an option,of course.

1 meter,white wall
Even though the mounted LEDs are cool white Cree XHP50,there is a difference in the color temperature,as the SRT9 wins in this respect with a cleaner beam.
The transition from hotspot to spill is also smoother on the SRT9.

At 5 meters distance,we can clearly see the difference in the beam.
Smaller,more focused hotspot for the SRT9.
It is also noticeable the specific for the first generation XHP LEDs darker zone in the center,which in most cases is not so noticeable,but yet it is there.

5 meters distance

The color beams are not symmetrical as we can see on the pictures.
All of the pictures are taken with a longer exposure time,to increase the visibility of the beams,as they are too dim for the previous exposure.
I did not take a photo of the UV light as it is very weak for seeing of me and the camera,as well.
The UV light is mostly visible by objects that glow while exposed to it.However,there is a small amount of white light that is easily visible and to some point helps us to see that the UV light is activated.

Positive and negative points according to my experience with the SRT9.
The way of closing the tailcap may be uncomfortable for some people.
Tail-standing option is not useful.
The lack of mode marking on the magnetic ring limits a little bit its functionality.
Overall,after using the SRT9 for quite some time,my impressions are only good.
I already mentioned my findings about the weak points and knowing a user can be very pleased with the use of this flashlight.
I like the quick change from white to color light.I like that we have a physical tail switch.The no-step white light adjustment gives us freedom to choose the needed brightness easily in any moment.
The pocket clip might be a great update over the EC4S for some users.
Normal cool white light from the XHP50 led.Quite powerful for most everyday uses.
The color leds,even their weak sides in terms of beam shape are quite useful and we do not get real UV light from any flashlight.You can actually check UV active money markings and other UV glowing stuff.
The uni-body bar shape stays very comfortable in the hand.

- Thank you everyone that has visited,read and enjoyed my reviews through the years!

Wednesday, September 13, 2017

Thorfire TK15 and TK15s FLReview (18650 EDC flashlights)

Thorfire TK15 and TK15s are compact EDC flashlights that run on the current most used battery size by most,the rechargeable 18650. Thorfire provided me these models for test and review.Read my impressions in the review below.

Thorfire TK15 and TK15s are almost identical flashlights,yet there are several differences in the design and operation. Both have a small metal side switch.
On the TK15s for mode changing.On the TK15 for On/Off and mode changing. The TK15s is slightly longer because of its physical tail switch.
The TK15 is equipped with a stainless steel "tactical" bezel.
Nice symmetric knurling on both models ensure stable grip.

Both flashlights come in the standard for Thorfire cardboard box with protective foam inserts.
The white sticker with the images,bar code and email address is originally not cut and ensures that the flashlight comes in brand new condition.

Thorfire TK15 Specifications and operation.

Thorfire TK15s Features and operation.

According to the specifications,the TK15 and TK15s support only 18650 batteries.
2xCR123A is not supported.

The TK15 has 5 constant brightness modes,while the TK15s has 4,as here one of the modes is replaced by the Bike light mode.
Both features Cree XP-G2 LED with very pleasant neutral white light.
According to the provided data the Highest modes have equal output of 1050 lumens.
The lowest modes of the TK15 are half the brightness of the TK15s's modes.
Identical reflectors with identical beam. 11200cd peak beam intensity-comfortable for close and mid range use.

My lumen measurements in an integrating sphere show:
Thorfire TK15:
Turbo= 1050 Lm initial output
High= 440 Lm
Mid= 140 Lm
Low= 24 Lm
Moonlight= hard to measure it correctly

Thorfire TK15s:
High= 1020 Lm initial
Mid= 430 Lm
Low= 55 Lm
Moonligt= hard to measure correctly

Size comparison with other Thorfire models-
Thorfire VG25- Thorfire TK15s- Thorfire TK15- Thorfire VG15- 18650 battery

Again,I am surprised by the quality of machine work that Thorfire does manage to maintain on most of their flashlights,especially while they are low priced budget models.
Black matte anodizing.Very consistent on my samples.
Clean square cut threads-anodized.
No sharp edges on the body allows comfortable grip.
Using the tail switch on the TK15s is easy and comfortable.
Both models allow tail-standing.
Thorfire TK15s disassembled

Very stable pocket clip on both flashlights.Should serve quite well for EDC use.
Both lights have two springs-one at the head and one at the tailcap.
All protected batteries that I have tested forsize compatibility fit well in the flashlights.

Thorfire TK15 disassembled

Here is a close up of both tailcaps.

Below is a graph with run/time measurements taken on the highest modes,combined with the Mid mode on the TK15.
As we can see from the graph,both flashlights are programmed to decrease their output 3 minutes after activation,which is expected knowing their maximum initial output of about 1000 lumens.Small flashlights like these two could easily overheat at this output,so the timed step down prevention is required here.
Yet as you can see from my second graph,if you use the flashlights in cold weather(cold ambient temperature) and need the maximum possible output,you can restart the light and get again the powerful illumination from these compact flashlights.
The drivers are programmed also for a second step down 30 minutes after the first.
The point of this step down is to protect the battery from excessive discharging,in the same time to give you a lot of time to continue with the work,if it can not be interrupted,to find the way home or to find a spare battery.
After first step down-
TK15s 405 Lm
TK15  395 Lm
After second step down-
TK15s 111 Lm
TK15   37 Lm

 To test how the TK15s reacts on restarting after step down,I waited a minute and restarted it.
It was a nice surprise to find that the output after restart is the same as the initial. Even after the fourth restart,the driver managed to recover almost identical output to the initial.

Beam profile

The beam on both flashlights is well balanced with good hotspot,soft not distracting corona and useful spill.
Neutral white light without noticeable yellow or pink tint.
Overall,I found the beam on both lights very good without leaving desire for something more.
It is just the right EDC beam for most of the users.
Check out the comparison beamshots below and find for yourself if the beam meets your personal preferences.

1 meter distance.White wall.
Thorfire TK15s Moonlight-Low-Mid-High-Turbo

Thorfire TK15s Moonlight-Low-Mid-High

Comparison with other flashlights.All flashlights on their highest modes.
1 meter distance.White wall.

 5 meters distance