Niteye EYE40 (4xXM-L U2, 4x18650) Review

fullfine · March 22, 2013, 10:04am

The EYE40 is one of the EYE series and new 4xXM-L U2, 4x18650 batteries high-output flashlight from Niteye.

Packaging is a cardboard box with built-in packaging foam. Included inside is the light, user manual, warranty card, removable grip handle, car charger, extra o-ring, nylon holster.
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Manufacturer Specifications from user manual :

Light source : 4xCree XM-L U2 LED
Battery : 4x18650
Output & Runtime :
Switch and dimming : Magnetic ring switch/dimmer
Circuit design : Constant current circuit, constant brightness
Working voltage range : 6~12.6V
Aircraft aluminum, Military type III hard anodized, stainless steel guard ring
Weight : 485g (excluding batteries)
Dimension : 66mm(W)x66mm(D)x145mm (D)
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The hard(type III) anodizing is not a solid black but an almost black (i.e., seems matte black combined with dark grey). There is no chips or damage on my sample. The labels on the head and battery tube are clear, and bright white against the background. There is hot warning mark & serial number on the head. The knurling is present over most of the battery tube except three sleeky rectangular sides. There is a laser etched maker logo & its URL on one of the rectangular sides. The other side has the model name, maximum lumens, and miscellaneous letters. There is nothing laser etched on the third.
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The light has mainly 2 parts (i.e. head and battery tube). There is a good quality battery carrier as well.
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There is a independent stainless steel bezel ring on each lens. The head base of the light has a raised tiny positive contact to contact with the spring loaded positive contact of the battery carrier. The negative contact rim surrounds the central positive contact. The EYE40 uses a stainless steel magnetic control ring which is conveniently located right below the head.
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The light uses AR coating lens and the purple hue is reflected on it.
The emitter was well-centered at each base of all reflectors. All reflectors are smooth, and very nicely finished.
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The square head has each different specific function on three sides except one side. (i.e., each side has a battery power indicator, a screw for removable grip handle fixing point, and a built-in DC 12V charging port. Because there’s no balancer in the light, it is recommended to use the 12V charging port not to often.
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There are small & shallow cooling fins at each corner of the head. There is no indent on the control ring to help with feel. The light has the half knurled control ring like other EYE series. There are firm detents at each output level, with a slight click as you enter into each output level. The total traverse of the control ring is 1/2 circumference (i.e., 180 degrees) of the light.
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The cross recess bolt shall be removed to put the handle in the female screw on the head. The handle perfectly fits into the female screw and is aligned, thanks to the recess on the head & the convexity on the handle. The handle has a large recess bolt & a washer, so that bolt is close to impossible to be loosened when using the light.
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The well-designed & sturdy handle gives a nice grip & externals. Personally, I like the light with the handle installed as it provides much better grip than a bit slippery battery tube.
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Knurling on the battery tube is not aggressive, so overall grip is not so good without installing the removable grip handle. There is a large negative contact spring at the bottom of the tube which holds the battery holder in place and prevents rattle. The wall thickness at the front of the tube is 1.4 mm. There is a stainless steel ring on the edge of the base.
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Screw threads look like trapezoidal-cut but nearly square-cut, and note that both male & female threads are anodized for head lock-out. They are smooth with no cross-threading or squeaking on my sample.
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The EYE40 uses a metal battery carrier that holds 4x18650 cells. It looks sturdy and well-made. The positive contact plate is slightly raised, and the negative contact spring has good elasticity. So all types (i.e., true flat-tops, wide and small button-tops) of 18650’s work fine. Longer cells may be somewhat tight, but all my protected high capacity (2600~3100mAh) cells fit. You can insert the battery carrier either orientation into the battery tube (i.e., it’s reversible), because it has same ends with positive and negative connection terminals. But you should be careful to insert the 18650’s into the battery carrier in the correct polarity.
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.!http://i1199.photobucket.com/albums/aa469/khk0603/EYE40/S-21.jpg !
You can see the fully loaded battery carrier with unprotected & protected cells. I don’t have any problem or issue to insert my shortest & longest 18650 cells into the carrier. But the positive contact plate may catch on the wrapper on the flat cells when removing them. I would like to recommend you to first depress the cells towards the negative spring before removing them. The battery carrier introduces little rattle if you shake the light laterally when it’s fully loaded with 18650’s unprotected . But no rattle with the protected 18650 cells installed in my sample.
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The light can tailstand perfectly thanks to the flat base.
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User Interface
On-off and all mode switching is controlled entirely by the stainless steel magnetic control ring located right below the head. Actually there are eight modes including “Off” (or stand-by mode) position as follows :
Strobe, Beacon (or Cruise Warning), Battery Power Check, Off, Low, Med., High, Turbo. But the control ring has 6 positions (or 6 form detents). This means one turn counterclockwise from “Off” will get Strobe, Beacon, and Battery Power Check by turns. These three modes will cycle sequentially. If you turn the control ring clockwise from “Off”, you will get brighter output, i.e., each turn clockwise will access to Low (single LED), Med. (two LED’s), High (three LED’s), and Turbo mode (four LED’s).
Each time you change mode, the battery power indicator shows the current battery state of charge relative to that mode for 2 seconds.

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Standby Current Drain
Due to the magnetic control ring design, the EYE40 is drawing a small current when the light is fully connected. I measured this current as 72μA. Since the cells are arranged in 2S2P, for 4x18650 (2600mAh) cells, that would translate into around 8 years before they would be fully drained. This is quite reasonable, not a concern. But I would recommend you to store the light locked-out when not in use.
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From left to right : VicLite 18650(2600mAh) protected, Niteye EYE40, Skilhunt DT-20, XTAR S1. I think EYE40 is reasonably compact and just slightly shorter than DT-20 given 4 cells vs. 2 cells.
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As mentioned earlier, the overall gripability seems better on the light with the grip handle installed. The overall build quality is very high on this light.
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Measured Weight

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The EYE40 comes with a basic nylon holster with a fixed belt loop & a velcro strap on the head. The light fits in the holster head-up only.
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[Edit : 2012.09.17]
PWM

There is a flickering at Low, Med., and High output detected by waving the light (i.e., can’t see it at Turbo), but can’t see it visually in practical use. I notice that there is no buzzing sound on any ouput levels on my sample. [Edit : 2012.09.17]
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Runtime
[Edit : 2012.09.09]

Fan Cooling

I ran Turbo & High mode runtime test for pre-production & production version under constant (or continuous) cooling using a fan.

1-1. Pre-Production Version

The EYE40 steps down on turbo after around 5 minutes runtime. This is a common feature on a number of heavily-driven high-output lights to protect from overheating. The runtime for 50% output of turbo & high is appr. 83 mins and 143 mins respectively in my test. The runtime for 10% output of turbo & high is same as above as the batteries protection kicked in.
The output on high is lower than step-down level of turbo. Regulation is maintained very nicely through Turbo & High. I assume this regulation is same to other output levels (i.e., Med. and Low).
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1-2. Production version

The production version steps down on turbo after 3 minutes & 8 minutes runtime.
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2. No Cooling

I have done a comparison of fan cooling and no cooling for production version, and measured surface temperature on the no cooling run.

2-1. Turbo Output

With fan cooling, output dropped to 46% initial output right after two distinct timed step-downs, and never dropped below 45% initial output. With no cooling, output dropped from initial output to 45, then slightly & gradually dropped to 43 initial output. The lack of cooling caused a very small drop in output over the time, but it’s practically impossible for you to see the difference visually.
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2-2. High Output

The lack of cooling caused a very small drop in output over the time, along with turbo output, but it’s practically impossible for you to see the difference visually as well.
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2-3. Surface Temperature

I measured with thermal probes attached to four points of the light for the no cooling run only. The room temp. was 26 degrees, and window was ajar on the test room. The resting temp. for EYE40 was 27 degrees. You can see the four points on the light where the thermal probes were set in pace as illustrated below.

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Turbo Output

Note that left y-axis is the relative output. The black, cyan, green, and blue lines represent surface temperatures of the light in degrees centigrade (celsius) should be read off the right y-axis.
The temperature continued to slowly rise in the course of the Turbo output run, reaching a max. 67 degrees at the points #1 and #2. As you can see the measured temperature, the light got quite hot. The temp. at the point #4 (i.e., battery tube) reached a max. 54 degrees.
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2) High output

The temperature continued to slowly rise in the course of the High output run, reaching a max. 62 degrees at the points #1 and #2. The temp. at the point #4 (i.e., battery tube) reached a max. 50 degrees. So you need the handle installed when using the light on turbo or high output as it not only provides better grip, but also prevent from getting burnt in the hand. Although my test condition is not the same as running the light outdoors, I would suggest you to hold the handle on the light when using it. [Edit : 2012.09.09].
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Beamshot

1. White door beamshot (about 50cm from the door)