Thursday, September 3, 2015

NITECORE EC4S REVIEW (XHP 50 LED)(2x18650) Updated Nov 11

This is a review of the dual 18650 battery powered flashlight Nitecore EC4S. It is the second released flashlight produced by Die-cast process of forming the aluminum alloy body.
Result of this process of forming is a uniform body with less thread connection points(only at the tailcap and front bezel) and minimum connecting elements,as this should ensure better shock resistant of the construction and better heat transfer through the whole flashlight.

Initially the review was made after testing a sample of the EC4S,which actually is a pre-release/prototype sample.
Later I got the final version from Nitecore and I am updating the review with new run time tests and pictures.
Many of the first comments below the review were about the XHP50 neutral white tint. Please note that the final retail version features a Cool White XHP50 LED and this is actually the main difference between the both versions I tested.

The EC4S shares the same design as the previously released model EC4.
Read also my EC4 Review for more impressions.

The same uni-body construction with black stoving-varnish finish.
The same dual side switch and user interface.
The main difference compared to the EC4 is the different,more powerful LED,which gives max brightness almost double the EC4 max brightness.
Note,that I am saying max brightness. It is a common practice manufacturers to post the maximum measured output on the box and in the specification list.
The reality though,is different. Most of the current high output flashlights loose their max output after minute of use(and even less) and can't provide the same high output at any battery discharge state. Check out the run time graphs attached to the review to see the actual output during a full discharge.
The higher output requires more batteries for higher voltage,or a special boost driver circuit.
Unlike the EC4,where two batteries were enough for stable output from the XM-L2 LED,the EC4S has a higher voltage LED and two batteries are not enough for maintaining stable output.

The first visible difference is...of course the tail-cap screw. For easier distinguish from its XM-L2 brother the EC4,the designers have decided to color the tail screw in reddish color,but not exactly pure red. I made all possible to represent it in my pictures,but can't guarantee your monitor will match the settings on my and will reproduce the color correctly.
Anyway,I did not have any information about the red tail and opening the box I told this a mistake.Am I receiving an entirely red flashlight?
I figured out shortly after that,only the tail screw is in red.
Not the most beautiful color,but definitely gives personality to the EC4S and makes it really easy to discern,if you have also the EC4.

The upgrade over the EC4 is the new LED,which was promised to gives a neutral white floody beam.
Initially it was announced the EC4S will be equipped with a Cree MT-G2 led,but recently it was changed to a Cree XHP 50 LED.
(link to the official Cree XHP 50 page)
The XHP50 used here is a cool white LED producing cool white floody beam.
The XHP 50 is a newer LED,I believe it is driven at 6V here.

This is a picture of the two EC4S samples I tested.
The Neutral white prototype version on left.
The final Cool white version on the right.
Both LEDs are Cree XHP50.
The neutral white version so far remains only a test version. If you buy the EC4S,it will come with a cool white XHP50.

The packaging and accessories.

Close up of the switch.
You can see well the stoving-varnish treated finish of the aluminum alloy body.

There is a blue indicator light under the silicone switch.
Can be used for battery voltage state,or as a location helping light.

Aluminum orange-peel reflector. Absolutely clean glass lens with anti-reflective coating.
Matte grey stainless steel bezel.

The two batteries have their own channel to prevent rattling,but there is no wall in between.
Batteries are always connected at the tailcap.No lock out possible by unscrewing the tailcap.

Protected batteries fit well in the body. Unprotected IMR work too.

A thick rubber/silicone gasket has the purpose to seal the tailcap and protect the interior from water and dust.
Two negative springs for more stability of the battery and better current flaw.
The screw head,which is the pinkish part on the picture below is the element you have to rotate when attaching the tailcap.
This is why this part is machined differently and has anti-slip knurling.
Initially my impression of the dark pinkish finish was that it is well anodized,but after some time of use,the finish started to wear out.
I would prefer more conventional anodizing on this part,which is often moving and in contact with fingers,gloves,etc.

The positive pole at the head has a physical reverse polarity protection.
I found it works with flat top IMR Keeppower 3500 batteries,though.

Standard 1/4 inch camera thread. You can use the flashlight mounted on a tripod.
Very useful for camping,or home work.

User Interface

Five brightness levels,plus 3 flashing modes.
Clicking the ON/OFF button activates/deactivates the light. Press and hold it for a second to activate Moonlight mode,directly from Off.
If you press and hold it,while the light is ON,this will activate the Blue indicator light under the button.Will turn the light Off,as well.
There is no memory for the indicator light. If you need the indicator light for easier locating the flashlight,you have to activate it manually,every time.

The second switch(with the four lines) is for mode selecting.
Press it to select among UltraLow-Low-Mid-High-Turbo modes,while the light is ON.
Press and hold it to activate Strobe mode. Press and hold again to activate Beacon and again to activate SOS mode.
Short press will return the constant light mode.
If you press and hold the switch for a second,while the light is OFF,this will activate Turbo mode directly.
Double click(the mode switch) starts Strobe mode immediately from OFF.

There is memory for the last used mode,except the 3 flashing modes.
The mode memory is extremely quick and does not require any special timings for ON/OFF to make it work.
If you leave it on High mode,it will start on High mode,no matter how quickly will turn it ON/OFF.

The UI is quite easy to remember and use. I did not find any trouble using it in real life situations.
Quick and accurate response from the driver.

There is one more function of the mode switch. If you press it briefly,while the light is OFF,the blue indicator light will show the level of the batteries by simple blinking.
Three flashes indicates battery voltage over 50%.
Two indicates battery voltage below 50%.
One flash means the batteries need to be replaced.

There is also switch locking option. Press and hold both switches together,for over one second to turn the light Off and lock the switches.
To unlock,press and hold both switches again,for over one second.

Run Time performance
This time I tested only using a small cooling fan.
The EC4S gets hot after few minutes on Turbo mode.
On High mode it does stay quite cool. This means,if you use it in the cold weather,it will not heat on High mode,at all-providing constant 1000Lm light.

There was no thermal protection activating during the tests.
There is a low voltage warning-the light starts blinking as a Strobe,when the battery voltage is too low.
As you can see from the graph,I waited at least 60 minutes for a low voltage protection,but there was no such.
Battery voltage after the test 2,6V. Really low voltage. What I am observing is that the battery protection also does not trip,if the discharge current is very low.

The discharge curve on Turbo mode shows that the output is highly depending on the voltage.
With decreasing the battery voltage,the brightness becomes lower.
The brightness is still impressive for a compact flashlight,but without a specific buck-boost driver,the output is performing as direct drive.

There is a difference in the performance on both tested samples.Yes,no flat regulation as many may expect,but for a 6V LED and no boost circuit,the result is normal.
The higher output is mostly a result of the different LED.The cool white LEDs usually show higher lumen output.
A small cooling fan was used to get the optimal performance.
No timed or thermal step down in my test.

A closer look at the first 60 minutes.

Here is a more interesting graph,comparing the High mode on the EC4S and Turbo on the EC4.
This is a comparison of the EC4 on its max mode,and the EC4S on High mode.
Lower output,longer run time.

Lumen measurements:
30 sec after activating.

Turbo mode 1990 Lm (2080 Lm initial) (the max output highly depends on the batteries)
High mode 934 Lm
Mid mode 392 Lm
Low mode 61 Lm
UltraLow mode 1 Lm

Pretty well spaced brightness levels.

Because of the electronically working dual side switch,the flashlight is in Standby mode,while the light is OFF.
In this state the driver consumes small current from the batteries.
My measurements show: 350µA on the prototype and 180µA on the latest tested version.
This will not be a problem if you use the flashlight every day,every week,but if you plan to keep it on the shelf without using it for weeks,or months,it is recommended to take out the batteries,to prevent unnecessary discharge.
It is definitely not a good choice for emergency flashlight that will stay without use,in case you need it someday.

Both EC4S samples I tested seems to have slightly different driver electronics,not only because of the lower Standby consumption,but also because of the way of controlling the brightness.
There is something like a PWM controlling on Low and Medium modes in the EC4 and EC4S NW. I don't detect any similar flickering in the Cool white EC4S sample.

Nitecore EC4 and EC4S side by side.
(neutral white EC4S sample on the two pictures below)

Crop of both LEDs,side by side.
Cree XM-L2 and Cree XHP 50

Because of the multi-core(die) design,the XHP requires an textured/orange-peel reflector for mixing well the beam and reducing the artifacts and darker zones in the center of the beam,which can obtain due to the empty space between the cores.
On a white wall I can clearly see different brightness zones in the center of the hotspot.
Outdoor this should not be so noticeable.
The produced light is Cool white light.


5 meters, 1/6sec

5 meters, 1/50sec

Some beam shots at 1 meter.
1 meter,1/20sec

1 meter, 1/250sec

1 meter, 1/500sec


I took outdoor beam shots when I was testing the neutral white sample and it is the EC4S on all pictures below.
The actual variant has much cooler white beam and is slightly brighter.
Beam shape seems identical.

~75 meters distance

I measured the EC4 1000Lm, the EC4S 1900Lm
Peak beam intensity according to the specifications= EC4 26000cd, EC4S 19600cd
I measured higher intensity on the EC4 than the stated,~30000cd. Did not measure the EC4S,yet.


Both flashlights
~75 meters

At close distance
Nitecore EC4S NW all modes.

Close distance
EC4S NW Turbo
EC4 Turbo

Close distance
EC4S NW High
EC4 Turbo (actually the same output)

I tried also the EC4S NW with the Olight M22 diffuser and the result is awesome!

Good points:
Clean well rounded design; Comfortable grip; Relatively lightweight; Can be defined as compact; Good build quality; Very high maximum brightness for its size;
Good relatively wide and floody beam;
Great dual switch User interface; Good run time curve on High mode,thanks to the higher voltage of two batteries; Well spaced modes;

Weak points:
Not regulated on Turbo mode; You will not get the max brightness every time you turn On the flashlight,or after a minute of use; No low voltage protection in my tests;
There are artifacts in the beam; No pocket clip ; High Standby consumption; No lock out the tailcap possible; The thermal step down is not programmed as needed;

Thanks for reading!

Thanks to Nitecore for providing the EC4S samples for test and review!