Warning: this review is a lot longer and more pic heavy than usual.
UPDATE JUNE 12, 2013: I have posted a pic-heavy comparison of the Turbo head versus Standard Head for all members of the GX/SX/MX25L2 family in a separate review here.
The GX25L2, SX25L2 and MX25L2 are three models in a new tactical series from Eagletac. Available in a number of configurations, my review samples came as the rechargeable Li-ion versions. These all feature two high-capacity Li-ion cells, shrink-wrapped in series (2x18650, 2x26650, and 2x32650, respectively) and built-in chargers. The overall build looks similar to the classic Streamlight Stingers and Mag lights, popular with law enforcement officers.
I've decided to break this review up into two parts – in this first part, I will review the GX25L2 and SX25L2 together, as they are very similar in features (i.e., both of my samples use the new Cree XM-L2 emitter). The larger MX25L2 (which uses a Luminus SST-90 emitter) has been reviewed separately, with appropriate comparisons to other high-output lights of that class.
This is going to be long one … and quite picture heavy!
Manufacturer Reported Specifications:
(note: as always, these are simply what the manufacturer provides – scroll down to see my actual testing results).
Common GX/SX25L2 Specifications:
- LED: Cree XM-L2 U2 Cool White (Neutral White XM-L2 T6 also available, expect ~7% lower output)
- Two groups of basic output modes, Tactical (100% / 10% / Strobe I / Strobe II) and Regular (100% / 35% / 6% / 0.1%) – user selectable
- Brightness level selected by loosening/tightening head/bezel
- Four levels brightness (user selectable sets) and seven hidden auxillary modes - Strobe/Strobe(Var)/Flash(Hi)/S.O.S.(Fast)/S.O.S./Becaon/Flash(Lo)
- Waterwhite glass lens w/ harden treatment
- Anti-reflective (AR) coating on both sides (96% transparency)
- HA III hard anodization aerospace aluminum (black)
- Smooth aluminum reflector
- Waterproof IPX-8 standard
- Features: User replaceable glass lens, Power gauge, Turbo boost technology, Battery reverse polarity protection, Tail stand, Upgradeable turbo-size head and reflector
- Warranty: Ten years performance guaranteed warranty
- Included Accessories: Spare o-rings, User Manual, Mil-Spec Para-cord Lanyard w/ quick attachment clip, Rechargeable models comes with 7.4V battery pack and spare waterproof charging cap
Specific GX25L2 Features:
- ANSI FL-1 Lumens for Cree XM-L2 U2 Cool White: 1002-878/456/87/7 lumens
- Runtime (3100mAh battery pack): 2/5.5/30/180+ hours
- Powered by 2x18650, 4xCR123A (as backup)
- Voltage range: 2.7V - 12V
- Beam Intensity (XM-L2 U2 version): 23,700 lux
- Beam Distance (XM-L2 U2 version): 337 yards / 308 meters
- Center spot angle: 7°, Spill light angle: 58°
- Dimensions: Head Diameter 1.5 inches (39.5 mm), Body Diameter 1 inch (25.4 mm), Length: 8.8 inches (224 mm), Weight excluding battery: 6.8 ounces (195 grams), Weight with battery pack: 10.1 ounces (288 grams)
- Non-rechargeable Base model comes with w/ smooth aluminum bezel
- Rechargeable Base model comes w/ built-in li-ion rechargeable port, 7.4V li-ion battery pack, battery isolation disk, removable stainless steel bezel
- Law-enforcement edition (All black) w/ built-in rechargeable port, 7.4V battery pack, black switch boot ring and smooth aluminum bezel (black)
- Optional YRGB kit: Base rechargeable model + aluminum filter housing (w/diffuser, yellow, green, blue lens), and rigid nylon holster w/ self-retention device, 12W AC-DC adapter (US/EUR), Automobile 12V DC adapter
- MSRP: unknown, but XM-L U2 rechargeable version with AC cable retails ~$150 (~$175 with YRGB accessory kit)
Specific SX25L2 Features:
- ANSI FL-1 Lumens for Cree XM-L2 U2 Cool White: 1049-932/522/98/9 lumens
- Runtime (4500mAh battery pack): 2.7/7.2/44/200+ hours
- Powered by 2x26650 Li-ion battery pack (included)
- Voltage range: 2.7V – 8.4V
- Beam Intensity (XM-L2 U2 version): 39,300 lux
- Beam Distance (XM-L2 U2 version): 433 yards / 396 meters
- Center spot angle: 6°, Spill light angle: 57°
- Dimensions: Head Diameter 1.8 inches (47 mm), Body Diameter 1.2 inch (31 mm), Length: 9.5 inches (240 mm), Weight with battery pack: 16.4 ounces (465 grams)
- Rechargeable Base model comes w/ built-in li-ion rechargeable port, 7.4V li-ion battery pack, battery isolation disk, removable stainless steel bezel
- Optional YRGB kit: Base model + diffuser filter, yellow filter, green filter, blue filter, rigid nylon holster w/ self-retention device, 18W AC-DC adapter (US/EUR), Automobile 12V DC adapter
- MSRP: unknown, but XM-L U2 rechargeable version with AC cable retails ~$165 (~$185 with YRGB accessory kit)
The lights come securely packaged in the new Eagletac cardboard box packaging. The lights come in a soft fabric pouch with a drawstring. Included accessories are a replacement metal charging port cover, extra o-rings, manual, and warranty card. On the GX25L2, the standard Eagletac wrist lanyard was also included.
On the rechargeable versions (reviewed here), a 7.4V battery pack is included with the lights. The appropriate AC charging cable for the model flashlight is also available (included here in a separate white box).
Note that all these lights are also available in "Turbo" models – where they come with a larger head with a larger reflector (for greater throw). I don't know if the Turbo head is available as a separate accessory at the current time, but they should be coming.
As part of this review, I have the included YRGB accessory kits for each model. These will be described further below, but include a holster and car charger, in addition to filter/diffuser covers.
From left to right: Eagletac 3400mA Protect 18650; Eagletac GX25L2, SX25L2, MX25L2.
From left to right: AW 2200mAh Protected 18650; Eagletac GX25L2, SX25L2; Nitecore MT40; Klarus XT-30; Crelant 7G5CS.
All dimensions directly measured, and given with no batteries installed (unless indicated):
Eagletac GX25L2: Weight: 198.3g (with battery pack: 290.1g), Length: 224mm, Width (bezel): 39.5mm
Eagletac SX25L2: Weight: 279.4g (with battery pack: 470.3g), Length: 239mm, Width (bezel): 47.0mm
Eagletac MX25L2:Weight: 468.7g (with battery pack: 744.2), Length: 266mm, Width (bezel): 62.0mm
Nitecore MT40: Weight: 244.2g, Length: 223mm, Width (bezel): 50.0mm
JetBeam BC40: Weight: 226.3g, Length: 224mm, Width (bezel): 48.5mm
Klarus XT30: Weight: 283.1g, Length: 247mm, Width (bezel): 58.0mm
Sunwayman T40CS: Weight: 296.7g, Length 227, Width (bezel): 63.5mm
Thrunite Catapult V3: Weight: 434.8g, Length: 254mm, Width (bezel) 58.0mm.
The GX25L2 is reasonably compact for the 2x18650 class. The SX25L2 and MX25L2 scale accordingly, given their larger capacity cells and bigger heads. But this review will focus exclusively on the GX and SX models - the MX25L2 is covered in a seperate review.
These new lights were clearly designed with law enforcement professionals in mind. They look a lot like what many LEOs and emergency workers would be familiar with (i.e., the classic Streamlight Stinger/Mag light shape and overall design). But don't let the classic form factor fool you - there is a lot that is different as well.
In terms of build, both lights are substantial, with good ergonomics (i.e. well balanced, good grip). Knurling is of reasonably high aggressiveness, and is present over the entire battery tube/handle, with some additional bands on the head and tail (GX25L2 model).
Anodizing is glossy black, hard anodized (i.e., type III), with no obvious chips or damage on my samples. There are a fair number of labels, and all are bright and clear (sharp white against the black background).
Screw threading on the tailcap is traditional triangular cut (and fairly fine), anodized for lock-out. Screw threads are square-cut (and thick) in the head region where mode switching occurs (more on that in a moment). Note that due to the design, only button-top Li-ion cells can be used (i.e., if you decide to forgo the included Li-ion pack/rechargeable version).
The lights can both tailstand, but the tailcap designs differ between these two models. The GX25L2 has a flat base with a side cut-out for a wrist-lanyard. The SX25L2 (and MX25L2 for that matter) has a raised area with a more substantial attachment point in the center. Likely due to the wider width of the SX and MX models, I find these lights tailstand more stably.
The lights both use an electronic side switch in the head for on-off – however, output mode selection and programming are controlled by head twist. The contact points in the head of the lights are fairly unique, as required for mode switching (scroll down for a UI discussion). There is also a charging port located directly opposite from the switch, with a screw-on metal cover.
For the switch and charging port, I am just showing the GX25L2 above, since it looks much the same on the SX25L2.
Switch feel is good for an electronic switch – there is a reasonable traverse, and the action is firm. Grip is good with the texturized rubber button cover.
The charging port looks like a fairly standard 12V DC port. Let's take a look at the respective AC chargers that came with my samples, starting with the GC25L2.
My GX25L2 charger has a smaller transformer plug than the SX25L2 or MX25L2, reflecting the lower charging current. As you can see above, it has a max 1A charging rate. Scroll down to the User Interface section of this review for a discussion of how the supplied charger functions.
The SX25L2 (and MX25L2) charger has a larger transformer head and charges at a max 1.8A charging rate. This higher rate is to be expected, given the higher capacity cells used in these lights.
Speaking of which, let's take a look at the bundled Li-ion battery packs:
The GX25L2 uses a 2x18650 battery pack – shown here as a single shrink-wrapped package. Based on the label, it looks like they just using two button-top Eagletac 3100mAh protected 18650 cells wrapped together in series.
You can thus use your own cells easily enough, but as will all multi-cell setups, you should make sure to only use well-matched cells (i.e., same brand and batch, similar history of use, consistent charge, etc.). Use of a pre-supplied battery pack takes the guess work out of this.
Note the charger will work with your own cells as well – but again, particular care should be taken when charging cells in series (i.e., important they both be at a comparable charge state, with well-matched characteristics).
The SX25L2 appears to use two 26650 cells in series, again shrink-wrapped as one battery pack. And again, you should be able to use your own 26650 cells – with the same warnings and caveats provided above.
The main advantage of the SX25L2 is going to be the higher capacity of the battery pack (i.e., 4500mAh vs 3100mAh per cell)
Reflector is fairly smooth on both the GX25L2 and SX25L2– but it's not quite as shiny as the MX25L2 sample that I have. Something else you may notice above – there is no longer the pronounced grid of bond lines on these new XM-L2 emitters (i.e., compared to the earlier XM-L). I will discuss this changes a little later in the review, but it could potentially translate into improved throw compared to equivalent output XM-L emitters.
Optional YRGB kit (also includes diffuser, car charger and holster:
Let's start with the diffusers. Note that the stock heads of this series all have a scalloped stainless steel bezel ring, replaceable with the screw-on diffuser/filter assembly.
One of the nice features of GX25L2 kit is the replacement bezel with flip-top diffuser/filter cover, similar to the G25C2 series. This unit is made of aluminum, and feels of high quality. Hinge mechanism is good, but was stiff on my sample. There is a metal retaining ring holding the glass lens in place (swappable between the frosted diffuser shown above and four colored filters). This is my preferred diffuser style, as you can easily switch between throw and flood by simply flipping the lid.
Unfortunately, the SX25L2 (and MX25L2 for that matter) only come with the standard screw-on style filters/diffuser. In these cases, the stainless steel bezel ring is removed and a plastic filter/diffuser holder is screwed in its place. A similar arrangement was seen in my various Eagletac M2/M3-series reviews. Note that the diffuser pieces themselves appear to be made of glass, for all models.
Let's take a closer look at the color filters, as there is a difference here as well:
The first observation is that for the most part, Eagletac is using high-quality optical glass filters (as opposed to just colored plastic or glass). You can see this on the GX25L2 shots above – all the filters reflect light of different color to what they transmit through. This is generally what you want, as you get the most accurate beam color when light is being properly filtered, as opposed to simply colored.
Of course, one of the challenges here is that white LEDs are somewhat deficient in certain regions of the color spectrum (including red). This will mean relatively low light levels with a proper red filer. Interestingly, on the SX25L2 and MX25L2 – but not the GX25L2 - the red filter is just a red-colored piece of glass. In my experience, these sorts of simple colored filters produce a fairly red spill, but a somewhat orange-red hotspot (i.e., the high intensity of the light tends to bleed through somewhat).
Since the GX25L2 and SX25L2 have very similar outputs and beam profiles, this allows us to do a direct comparison of the relative merits of these two approaches to red filtering.
(I forgot to label the pics, but the exposures are my standard 1/25sec, 1/100sec, 1/800sec and 1/1600sec, all at f2.7, ISO80).
As expected, the red optical filter on the GX25L2 lets less light through overall, but it has a "truer" red tint. The SX25L2 has a more orangey-yellow hotspot, as the high-intensity light bleeds through.
Along with the YRGB filters and diffuser, the kit versions also come with a car charger and holster:
The holsters for the GX25L2 and SX25L2 have a closed bottom section, and hold the light to just below the head. Hold was good, and enough of the light sticks out, allowing for easy draw access.
Turn the lights on/off by the electronic switch. Press and hold for momentary, press-release (i.e. click) for locked-on.
Interface is somewhat similar to the G25C2-series, with a few updates. There are four output levels controlled by how loose/tight the head is (i.e., the four levels are accessed in sequence from head fully tight).
Note that as with the G25C5, the physical turning distance between the levels is not equidistant. As soon as you loosen past fully tight, you drop down to the second level. You drop down again to the third level after a ~90 degree turn, and similarly again for the fourth level after another ~90 degrees. This means that after ~180 degree turn from tight, the light is in the lowest mode. It remains in this mode until you complete almost a full turn from fully tight (at which point the light shuts off).
There are two possible groups of output modes available - Tactical (100% > 10% > Strobe I > Strobe II, in sequence) and Regular (100% > 35% > 6% > 0.3%, in sequence). You can switch between the two groups by turning the light on max (fully tight) and loosening the head to the second level and then back to tight, repeating this sequence five times in five seconds.
A new feature on these xX25L2-series lights is the ability to rapidly access a momentary Turbo from any head position by a press-and-hold of the switch when On. You can similarly access strobe at any time by a double press and hold (i.e. click and press-hold). Simply release the switch to return to your previous head-set level.
To access the hidden auxiliary modes, do a quick loosen-tighten twist of the head (from first level tight to third or fourth level and back again). Repeat this twist to advance through the modes. Mode sequence is: Strobe I > Strobe II > Hi-Flash > SOS I > SOS II > Beacon > Lo-Flash, in repeating sequence. Turn off the light or loosen the head to quit the hidden modes. I will describe these modes in more detail below.
There is an "energy saving feature" where the light reduces output by 20% after 200 seconds in Turbo. Unlike the G25C2, I see no way to toggle this feature off. Of course, you can always turn the light off-on to restart the max output mode.
There is a battery charge status indicator that comes on when you first turn the light on, or switch output levels. For the initial 10 secs in a given mode, the LED indicator above the switch will glow solid blue when 60-100% charged (on Turbo) or 20-100% charged (on Lo). It will glow solid red for 25-60% charged (on Turbo) and 5-20% charged (on Lo). It will flash red when 0-25% charged (on Turbo) or 0-5% charged (on Lo). This is reasonable contextual information, as solid red and flashing red are good indicators of relative battery runtime left at the current set level.
For charging the lights, you connect the appropriate charger adapter into the DC port on the light.
The GX25L2 uses either a supplied 10V/1.2A charger or a 12V/1A charger, while the SX25L2 uses either a 10V/1.8A charger or a 12V/1.5A charger. Eagletac claims both light use a constant current-constant voltage (CC/CV) algorithm.
When you first connect the charger, the charging light will go solid blue, indicating charging has begun. Once the batteries are fully charged, the LED will turn to a dim blue. A built-in timer shuts off the charger after three hours (i.e., the LED indicator turns off).
The manual warns that if the batteries are fully discharged, three hours may not be enough time to fully charge them (i.e., may be only ~90% charged at that point). Simply unplugging the charger and plugging it back in at any point restarts the clock, and will allow you to complete a full charge. Basically, you want to make sure the charger goes to a dim blue before it shuts off, to be sure the batteries are fully charged. You can disconnect the charger once this point is reached.
In my testing of these lights, the chargers all terminated at ~8.31-8.32V. That would translate into ~4.16V per cell, which is on the conservative side for a Li-ion charger (i.e. typically, ~4.2V fully charged). But it is always better to slightly under-charge than over-charge your cells, in terms of long-term battery stability (even if it means not being at fully charged capacity).
From a fully discharge state, the charging time for the GX25L2 with the 12V/1A charger was about 2.5 hours (so no worries about built-in timer shutdown). But for the SX25L2 on the 10V/1.8A charger, it took about 3hr 10mins for a full charge – so you may need to re-plug the charger as the manual suggests.
For more information on the light, including the build and user interface, please see my video overview:
Video was recorded in 720p, but YouTube typically defaults to 360p. Once the video is running, you can click on the configuration settings icon and select the higher 480p to 720p options. You can also run full-screen.
As with all my videos, I recommend you have annotations turned on. I commonly update the commentary with additional information or clarifications before publicly releasing the video.
There is no sign of PWM that I can see, at any output level, on any light – I presume the lights are current-controlled.
My GX25L2 and SX25L2 were very consistent in their strobe modes, so only a single trace is provided for each below.
The main strobe is standard high frequency strobe, measured at 9.4 Hz on my GX25L2 and SX25L2 samples.
The second strobe mode is an alternating or "oscillating" strobe, switching between 6.4Hz and 14.5Hz roughly every 2 secs. Definitely disorienting.
Hi-Flash is basically a full power slow strobe/beacon mode. Frequency was a reasonable 1.6 Hz in my testing. Note that the deflection spikes you see above are just the on and off signals of the pulse (i.e., it spends roughly half the time on, half the time off, with each pulse).
The "fast" SOS signals the full SOS sequence (dot-dot-dot, dash-dash-dash, dot-dot-dot) in just under 3 secs. Note again that the traces above refer to both the on- and off-signal for each pulse of light.
In contrast, the "slow" SOS takes just under 3 seconds just do the "S" (i.e. dot-dot-dot), and about 4 second to do the "O" (i.e., dash-dash-dash), with a good 3 seconds in-between each Morse code letter. Personally, this seems far more useful than the rather frenetic initial SOS mode.
Beacon is a slow full output flash (almost 2 secs long), re-occurring approximately every ~14 secs (i.e., a very slow beacon)
Lo-Flash is a lower output, slower frequency strobe/beacon than Hi-Flash. I detected 10 flashes in a ~20 sec period (i.e. about 0.5 Hz).
A standby current drain is inevitable on these lights, due to the electronic switch in the head. Here is how the three members of this class compare, on their standard battery packs:
Note that the above are approximate, as the lights briefly come on with a ~400uA initial reading (corresponding to the LED charge indicator flash upon connection), which quickly drops down to <170uA within a second. After about the 30 secs, it seems to stabilize at the readings above, but it may be continuing to drop down.
Given the rated capacities of the cells (i.e., 2x in series, which means you compare the mAh of a single cell), those currents would translate as follows:
GX25L2: 3100mAh cells = 2.3 years
SX25L2: 4500mAh cells = 3.4 years
MX25L2: 6000mAh cells = 4.3 years
These standby drains are pretty inconsequential, and not a concern. That said, I do recommend you store the lights locked out at the tailcap when not in use, to prevent the risk of accidental switch activation.
And now, what you have all been waiting for. All lights are on their standard battery, or 2xAW protected 18650, and about ~0.75 meter from a white wall (with the camera ~1.25 meters back from the wall). Automatic white balance on the camera, to minimize tint differences.
The beam patterns are what you would expect for lights with reflectors this size. Overall spillbeam width is fairly typical, with the GX25L2 being slightly wider than the SX25L2 (or MX25L2 for that matter, not shown). Overall throw is reasonable for the class, with a relatively clean hotspot and corona (i.e., fewer artifacts than most lights with smooth reflectors I've tested).
Unfortunately, we have a lot of snow on the ground here in Canada at the moment (early March). So it would not be too easy (or valuable) to try and take outdoor beamshots in my usual location.
In the meantime, here are some indoor shots. These will at least allow you to compare the throw and spill of the three lights. For your reference, the back of the couch is about 7 feet away (~2.3m) from the opening of the light, and the far wall is about 18 feet away (~5.9m). Below I am showing a series of exposures, to allow you to better compare hotspot and spill.
As you can see a bit better here, the SX25L2 has a more tightly focused hotspot for greater throw. But the overall amount of light produced on Turbo isn't that different from the GX25L2. The MX25L2 is a different matter, as is discussed in its own review.
I will update with outdoor comparisons when weather permits.
UPDATE: I have posted a pic-heavy outdoor comparison of the Turbo Head versus Standard Head for all members of the GX/SX/MX25L2 family in a separate review here.
All my output numbers are relative for my home-made light box setup, a la Quickbeam's flashlightreviews.com method. You can directly compare all my relative output values from different reviews - i.e. an output value of "10" in one graph is the same as "10" in another. All runtimes are done under a cooling fan, except for any extended run Lo/Min modes (i.e. >12 hours) which are done without cooling.
I have devised a method for converting my lightbox relative output values (ROV) to estimated Lumens. See my How to convert Selfbuilt's Lightbox values to Lumens thread for more info.
Throw/Output Summary Chart:
My summary tables are reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. Please see http://www.flashlightreviews.ca/FL1.htm for a discussion, and a description of all the terms used in these tables. Effective July 2012, I have updated all my Peak Intensity/Beam Distance measures with a NIST-certified Extech EA31 lightmeter (orange highlights).
Consistent with the beamshots, my lightbox and ceiling bounce measures don't find a big difference between the GX25L2 and SX25L2 models – but the SX model does throw further.
In terms of throw, I notice that all three models (with Standard head) exceed the specs that Eagletac provides on their website. It may be that the online specs have not caught up with the new XM-L2 U2 emitters (although I notice that the reported XM-L2 U2 output specs seem pretty accurate - see below).
UPDATE: I have updated the table above with the results of the Turbo Head versions of the GX/SX/MX25L2 family. See my separate Turbo Head review for a discussion.
My output lumen estimates seem to track quite well across the board with the Eagletac published specs for these models.
XM-L2 U2 vs XM-L U2 – what's the difference?
You might be wondering why the output and throw of the XM-L2 U2 samples seem a bit higher than other lights in these classes (compared the original XM-L U2 models). Basically, these new XM-L2 emitters deliver "up to" 20% more lumens and lumens-per-Watt than the classic XM-L of comparable output bin number (see Cree XM-L2 spec sheet here).
That said, directly comparing back to XM-L is complicated by the more stringent testing and reporting measures Cree is now using for XM-L2 binning. XM-L emitters were previously output bin rated by luminus flux @350mA, @25 degree C. With the XM-L2, Cree has switched to a more representational (but more stringent) @85 degree C for binning purposes. This means that the XM-L2 output bins are considerably brighter than the XM-L output bins with the same bin number.
As for how much, there is actually an easy conversion. If you look up the spec tables under the same conditions, you will see that the new XM-L2 bins are exactly two bin steps brighter than the same bin number on XM-L. So a XM-L2 U2 is basically what a XM-L U4 would have been (if such a beast had ever existed). This part of the reason for the switch to the new process - there is now more "headroom" on the new XM-L2 platform, and higher output XM-L2 emitters can ultimately be produced.
In terms of lumens though, you have to keep in mind how the binning process works. Given the ~7% range within each bin, this means that for any given specific XM-L2 sample could be anywhere from ~7-20% brighter than a comparably bin-numbered XM-L sample. This is presumably where that "up to" 20% brighter statement comes from in the Cree literature. But you need to keep in mind that on average, a XM-L2 U2 should be ~13% brighter than a XM-L U2. You really have to think of these things statistically – the bins are a range, and you don't know where exactly in the range any given sample will fall.
The other significant change is the move to a single die LED on the XM-L2. As you will see in the close-up pics earlier in this review, gone now is the large grid of bond wires. This should allow for better optical control and focusing. It is hard for me to be more precise, as I would need to compare the same light with different emitters to know how they truly compare in practice. But I note my NIST-certified center-beam lux measures for these XM-L L2 lights are higher than Eagletac's reported specs.
Let's start with how the three new models compare to each other, on Turbo and Hi:
As previously noted, there is little difference in output on between the GX25L2 and SX25L2. Basically, you get further throw on the SX model (due to the larger reflector), and much greater runtime (due to the larger capacity 26650 cells). In my testing above (for Hi and Turbo), you get ~55% longer runtime on the SX25L2 compared to the GX25L2, for roughly equivalent output.
The second point is that the SST-90-based MX25L2 is much brighter on its various modes (which I discuss further in my dedicated review of that model). But thanks to its even greater capacity cells, it is able to provide even longer runtime than the SX25L2 for equivalent output.
You will also notice that on Turbo, there is a step-down after 200secs runtime (as indicated in the manual).
Let see how the GX25L2 compares to other 2x18650 lights. To help with these comparisons, I have tested the GX25L2 on my standard testbed of AW 2200mAh Protected 18650s (i.e., all lights tested on equivalent batteries).
There seems to be a definite efficiency advantage on these XM-L2 U2 equipped lights, compared to a lot of the older XM-L lights. Note that most of my older XM-L lights are presumably T5 and T6 output bins, given that no bin was specified for them.
Again, keep in mind that the GX25L2 runs considerably longer on its stock 3100mAh cells than on the 2200mA AW cells used above. In case you are curious, here is how it performs on its stock battery pack relative to another set of 3100mAh cells:
UPDATE: Eagletac sent me a couple of their 3400mAh protected 18650 cells (presumably based on the Panasonic NCR18650B), which I have added to the comparison above).
Basically, other 3100mAh cells (based on the Panasonic NCR18650A core) perform pretty close to the stock Eagletac 3100mA cells included (even though the stock charger only charges them up to ~4.16V each). The Eagletac 3400mAh cells (presumably based on the NCR18650B core) do even better, as you would expect.
And now the 2x26650-based SX25L2, compared to some of the multi-18650-cell and multi-emitter options out there:
Max output of the SX25L2 is in keeping with other single-emitter options out there. As you would expect, the 2x26650 SX25L2 lasts longer than a good current-controlled 3x18650 light (on the lower capacity 2200mAh cells that I use). If you were using 3100mAh cells in a good XM-L2 light, I would expect comparable runtimes to the SX25L2 for similar output.
In conclusion to all of the above, the GX25L2 and SX25L2 are very long-lasting lights – thanks in part to their higher output XM-L2 U2 emitters, as well as Eageltac's excellent current-controlled circuits. Regulation patterns are also extremely flat, for all levels tested.
Flat-top cells will not work in these lights, due to the physical reverse-polarity protection feature on the positive contact terminal in the head. I recommend you stick with the supplied battery pack, or use equivalent button-top cells.
As with other Eagletac models where output mode is set by the degree the head is tightened, you need to keep all contact surfaces in the head scrupulously clean. Otherwise, you may experience mode switching problems due to contact surface issues.
The charger has an automatic shut-off feature after 3 hours – which may not be sufficient to fully charge a depleted battery pack on the SX25L2. Simply restarting the charge cycle will complete the charge.
All three of my samples only charged to ~8.32V (i.e. ~4.16V per cell), which is a little on the low side – but this is preferable for the long-term health of your batteries anyway.
I am a little unclear about use of primary CR123As in the GX25L2. The manual makes no mention of supporting them, and lists the max voltage range as 12V (which 4x new CR123A would slightly exceed). However, the online spec sheet reports that CR123As can be used "for backup use". I haven't tested 4xCR123A in light, but this appears to indicate they can be used.
Ok, this was an incredibly long review. But that's because there's a lot to talk about here – despite the traditional Stinger/Maglight shape, the GX/SX/MX25L2 line is quite distinctive in its operation and features.
To begin, I quite the like the builds. The lights are solid, with good grip and ergonomics for their classes. These are the kind of lights that you can easily hand to anyone and they would know how to turn it on. Basic mode changing is simple, with a single piece of instruction (i.e., loosen the head to lower the output). This elegant interface is quite intuitive, and immediately allows you to get a lot out of your light. For example, it allows you pre-select what mode your light will turn on in, which is important to many users.
This straight-forward interface belies a more sophisticated set of features: you actually have the choice between two sets of output modes, plus all the "hidden" blinky modes. Eagletac certainly provides more options than most in this regard. There are also some nice tweaks, like the ability to jump directly to Turbo or Strobe from any mode when On by a simple button press. And of course you have both momentary and clicked on available to you.
Standby current for the main switch has been kept very low, so self-discharge is not a concern. And you can easily lock out the lights at the tailcap for long-term storage.
I like that you can use your own 18650/26650 cells in these lights, or the bundled battery pack (which contains good quality, high-capacity cells). The charging system worked well in my testing, with faster-than-usual charging times (thanks to the custom charging circuits/cables). This is certainly one of the better implementations I've seen for in-light charging (and car adapters are included with the kit options).
The kit versions are definitely worth it in my view – if nothing else, for the good diffuser/filters. I particularly like the aluminum flip-top diffuser bezel for the GX25L2. Solid and well made, it offers the best of both worlds – max throw or full flood at the flip of finger. The SX25L2 has the more traditional individual screw-on filter design, which is still quite serviceable.
Performance-wise, output/runtime efficiency is excellent on my samples – thanks in part to the new XM-L U2 emitters and the high-capacity cells. But with whatever emitter you choose, you can rest assured that Eagletac's current-controlled circuitry remains top-of-class in terms of efficiency and regulation.
Beam patterns were good on all my samples, with reasonable throw and minimal artifacts. It is interesting that Eagletac plans to offer optional "turbo" heads for even greater throw – giving you even more customizable options for these lights. And you also have the option to go with Neutral White emitters.
There really is a lot here that appeals, if you are in the market for this form factor light. I could easily see these lights supplanting the classic law enforcement officer carry light (i.e., the Streamlight Stinger or Maglight). With their wide output range, intuitive user interface, high-charge capacity with rapid charging capability, these lights are clearly designed to appeal to a wide market. It really comes down to what size/capacity/throw is best suited to your needs. Definitely worth a look!
UPDATE JUNE 12, 2013: I have posted a pic-heavy comparison of the Turbo head versus Standard Head for all members of the GX/SX/MX25L2 family in a separate review here.
GX25L2, SX25L2 and MX25L2 were provided by Eagletac for review.