Monday, December 2, 2013

Fenix TK51 Review,1800 Lm,Dual beam light

Fenix is well known with the high quality of every detail in the flashlight.Being one of the best flashlight manufacturers is not enough,they seek to improve the flashlight functionality with new design never seen before.
Fenix TK51 and TK76 are new lights in the outdoor/search line flashlights.They have more than one LED.Each of them can be used separately thanks to the user interface that gives you a wide selection of lighting modes and beam.
I will review for you Fenix TK51. It has two XM-L2 LEDs,two different reflectors-one for wide beam,one for spot beam.See more in the review below.

Dual reflector.Two Cree XM-L2 LEDs. 1800 lumens output.
Excellent anodizing,typical for Fenix.Black matte finish. Smooth surface,well rounded edges.
Note that the test flashlight is prototype and arrived without retail packaging(plastic case) and even that it is in excellent condition.
Shallow cooling fins with well rounded edges. Top notch machining.
Three push buttons for lighting modes controlling.

1800 Lumens
900 Lumens Spot Low-Mid-High-Turbo
900 Lumens Flood Low-Mid-High-Turbo
Peak beam intesity 45200cd
Beam distance 425m
Impact resistance 1m
Water proof IPX-8
Utilizes two Cree XM-L 2 (U2) LEDs with a lifespan of 50,000 hours.
Uses three 18650 rechargeable Li-ion batteries(in parallel).
188mm (Length) x 48mm (Diameter)
430-gram weight (excluding the battery)
Digitally regulated output with low-voltage indicator.
Reverse polarity protection guards against improper battery installation.
Three button interface for fast and convenient operation.
Made of durable aircraft-grade aluminum.
Premium Type III hard-anodized anti-abrasive finish.
Toughened ultra-clear glass lens with anti-reflective coating.

A few pictures for size comparison and to see how the light stays in my hand.You can see also position of the buttons.

The light fits very well in my hand. The battery tube has knurling which provides stable grip.

The three push buttons have good size(for my thumb).Short move. All three buttons on my sample(test sample) have different sound.
I feel them a little too easy to press.There's no protection for the buttons,so you have to carry it with care(the light is about 600g and this weight could press the buttons accidentally.
The mode switching buttons are on the top.They are close to the wider(reflector) part.Could be a problem for very big hands,but in my case this helps me easy to find the buttons and to place my thumb just in the right place.
The big button is for On/Off and momentary Turbo(Flood+Spot).

The testing light is provided for the TK51 testing campaign.

Big 41mm Smooth reflector for Spot beam.
Small 12mm slightly textured reflector for Flood light.
The glass is one piece for both reflectors.

Two loops for strap attaching.
Stable tail-standing.

Battery tube is sufficient thickness.

Battery holder for 3 18650 size batteries. Big O-rings ensure water sealing.

Gold plated contacts.Center contact for the + and two side contacts for the - pole.
Anodized rectangular cut threads on both sides.
Perfectly made.Very smooth screwing.

Battery holder has gold plated ring for negative pole and center spot for the positive.

The holder itself is made of thick plastic.Sturdy construction.
Big positive contacts. Dual springs ensure maximum good contact with batteries ans minimum resistance in the contact point between battery and spring.
The batteries are connected in parallel. I like this way of connecting.We don't have to worry too much how to insert batteries because all they are placed in one direction. Batteries connected in parallel have equal voltage. If one of the batteries has lower voltage the other two will charge it to level where all three batteries have equal voltage. This is the the safest way of powering a flashlight with multiple batteries.
Button-top and flat-top batteries fit well.

Protected batteries fit a little bit too tight in the holder. It's hard for me to remove batteries with short nails.

I used for my review 3x 18650 Keeppower batteries, 3x3400mAh =10200mAh

Aluminum reflector 41mm smooth + 12mm textured.
Toughened,ultra clear glass lens with anti-reflective coating.
Two Cree XM-L2 U2 LEDs.

User Interface

Fenix TK51 has very interesting and easy to use user interface.Needs a little time to get used to it,but is quite convenient.The Flood and Spot beams are controlled separately each other.This gives a wide selection of combining Flood light and Spot light in needed proportion.
Both Flood and Spot beams have their own button which switching between Low-Mid-High-Turbo-Off.

4 brightness modes for each beam Low-Mid-High-Turbo controlled by two electronic(push button) switches.
Momentary Flood+Spot Turbo,momentary Strobe.

Single beam
Low 10 Lumens / 420h
Mid 150 Lumens / 27h
High 400 Lumens / 9h
Turbo 900 Lumens / 3h 30min

Two beams
Low 20 Lumens/ 210h
Mid 300 Lumens/ 13h 30min
High 800 Lumens/ 4h 30min
Turbo 1800 Lumens/ 1h 45min

When the light is Off.
Pressing the Flood or Spot button will activate one of them in Low mode.No memory for this buttons when they are pressed from Off.
Press again shortly to change the mode to Mid-High-Turbo-Off and again Low-Mid-High-Turbo-Off.
You can turn the light Off by cycling through the modes or by pressing the bigger button.

When one of the beams(Spot or Flood) is activated.
Pressing the switch on the other not activated beam will activate it not in Low mode,but in the last used mode.This needs a little time to get used.
Both beams activated can be turned Off by the big(central) On/Off button.
Next time when you press the On/Off button,the light with start with the last used mode on both beams.

There's a momentary/instant Turbo mode which can be activated by press and hold the On/Off switch from Off or On.It will activate both beams Spot and Flood on Turbo.When you release the button the light will return to the brightness used before activating momentary Turbo.
TK51 has also a Strobe mode.It can be activated only momentary by press and hold one of the beam mode buttons from Off or On.
Batteries Keeppower 3400mAh.

I measured how the brightness changes when the TK51 is on Turbo(Flood+Spot).
Fenix TK51 has integrated temperature sensor which decreases the output when the flashlight overheats. In cold weather,etc. when the aluminum is cold the light stays at normal temperature even on a full turbo mode.
In the first test I left the flashlight on a table,without moving it or cooling with air.This will show how the flashlight will work if you use it for room or camping light,etc.

In the second test was used a cooling fan to see how cold ambient temperature will affect the output and the time before step down(decreasing the brightness to protect from overheating).
As you can see from the graph,the difference between cooled and not cooled light is not so much.

9,5min before step down when cooling.
7,2min before step down with no cooling.
The difference is not so much.The light was hot without external cooling,but cooled with a cooling fan the body of the light was with quite normal temperature.
In my opinion,TK51 could maintain the Turbo mode much longer when used in cool place.

This graph shows the light output, Flood Turbo Vs Spot Turbo.
I measured the Flood light only for 100 minutes and the Spot light for 134 minutes.This is not full runtime graph.
There's no a step down that can be seen using Flood and Trow on Turbo simultaneously.
Cooling fan was not used in both tests.Ambient temperature 21C.
Batteries Keeppower 3400mAh.

Short video,presenting the UI and design specifics.
(turn on annotations)

The light from the both LEDs is cool white,clean without greenish or blueish tint.Good color rendering.
The small reflector gives wide,smooth floody beam.
The bigger reflector gives very well concentrated spot beam with very good throw.
Both lights together give a whole wall of light.

1 meter, White wall, 1/20s



Other flashlights

5 meters, 1/6sec
Flood- Click on the pics to see them larger.



Other flashlights

Outdoor beamshots

~35 meters, Foggy weather,4sec ,ISO 80
Flood -
Click on the pics to see them larger.



Other flashlights

Some of the lights used for comparison.
Lumintop TD16, Klarus ST11, Olight M22, Fenix PD35, Fenix TK51

TK51 Flood, Low-Mid-High-Turbo

TK51 Spot, Low-Mid-High-Turbo

TK51 Spot+Flood Turbo

TK51 Spot+Flood Turbo

River test

I tested the TK51 in the river.I wanted to see what will happen if I drop it accidentaly in the water when I am on camping,fishing,etc.
Fenix TK51 successfully passed the test. No leaks or fog under the glass lens.The water was pretty cold. All buttons work under water.

In conclusion.
Fenix TK51 gives a great selection of beam and brightness modes which makes it a light suitable for different situations.Very useful Flood beam excellent for close and medium range work.Spot beam for medium and long range illumination. Both beams give very bright beam that has all needed-bright spill and spot with good throw,with no darker zone between them.
Built quality is very high,as usual for Fenix. With a little better set temperature control TK51 could be even better light.

Thanks for reading!
Any questions are welcome.

Fenix TK51 was provided by Fenix for test and review as part of the TK51 Global testing campaign.