4Sevens Maelstrom X10 (XM-L, 26650) Review: RUNTIMES, BEAMSHOTS and more!

Originally posted: July 22, 2011
Last revised: August 21, 2011

Warning: pic heavy, as usual.

The X10 is the latest offering in the Maelstrom line from 4Sevens. Featuring a 26650 Li-ion battery, it looks a lot like the S12 - only now with a Cree XM-L emitter (X10) instead of the Luminus SST-90 (S12).

Manufacturer's Specifications:

Packaging is fairly typical for the Maelstrom line. Included inside is the light, good quality belt pouch/holster, manual, and spare o-rings. There is no wrist lanyard (no attachment point on the light). Note that there is also no battery included – you must purchase a 26550 Li-ion rechargeable and charger separately. Conveniently, 4Sevens just happens to sell these …

Here’s what the required battery looks like:

My review sample came with a blue-wrapped 26650 (the original S12 used a green-wrapped 26550). I’ve asked 4Sevens, and have been informed that the two batteries are different, with the X10 blue-wrapped battery reformulated for the lower load with the XM-L. The S12 batteries will work in the X10, but not the reverse.

From left to right: 4Sevens X10 Maelstrom, G5 Maelstrom, Quark 123-2; ITP R01; NiteCore IFE2

From left to right: AW Protected 18650, 4Sevens Protected 26650, 4Sevens X10, Fenix TK35, Sunwayman M40C, Eagletac M3C4.

All dimensions are given with no batteries installed:

X10: Weight: 156.9g, Length: 135.5mm, Width (bezel): 46.0mm
X7: Weight 146.9g, Length: 151.5mm, Width (bezel): 38.7mm
G5 : Weight: 145.5g, Length: 156mm, Width (bezel): 38.9mm

The light is wider than typical, due to the 26650 cell (i.e. 26650 refers to the battery width in mm, 26650 refers to the length in mm, 26650 refers to a cylindrical cell). But overall length is well within the standard range for lights that use this typical 65mm cell length.

Compared to the 2x18650 class of lights, the X10 seems downright tiny. The reason for this size comparison will become obvious once you see the output …

The X10 is a solid light. Black anodizing (manufacturer claims type III = HA) is slightly glossy on the smooth areas, like the rest of the Maelstrom line. Knurling is not overly aggressive, although there is more of it than typical on these sorts of lights, and I found the grip to be good. Lettering is bright - clear and sharp.

There are a generous number of square-cut machinist threads (anodized for tailcap lockout).

Note the switch is not an actual clicky. Pressing the plastic button simply pushes forward the circuit board slightly. This allows contact for momentary-on when the tailcap isn’t fully tightened. When fully tightened, the tailcap is locked-on and the button has no effect. Scroll down to my interface section for a discussion.

The X10 uses the Cree XM-L emitter, well centered on my sample, with a smooth reflector (although there are some fine concentric rings in it). I don’t have a S12 to compare, but it looks like they are using the same build for the X10, with a flat area of the reflector right around the smaller emitter in this case.

And now the white-wall beamshots. All lights are on their respective single cell rechargeable Li-ion battery source, 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.

Output is quite high for a single-cell light – 4Sevens is clearly driving the XM-L at a relatively high level. The X10 has a very wide spillbeam, wider than most lights. This is likely due to the fairly wide and shallow reflector. However, the beam also has some artifacts in it up close, especially around the hotspot. There is also a very pronounced tint shift in the large and sharply defined secondary corona on my sample.

UPDATE AUGUST 21, 2011: I have now done 100-yard outdoor beamshots, in the style of my earlier 100-yard round-up reviews.

User Interface

The X10 seems to have exact same interface as the S12 which preceded it.

Both lights use a pressure-style switch. When the tailcap is fully tightened, the light comes on and stays on. With the tailcap loosened a quarter-turn or so, you can press the switch button to activate the light in momentary mode (i.e. release the pressure switch, and it shuts off).

Mode switching between the two output modes is controlled by rapidly turning the light off and back on again within 1 sec. You can do this with either the momentary pressure switch or by twisting. If you wait longer than 1 sec before reactivating, the X10 memorizes the last mode you were in (i.e. comes back on in the last mode used next time you re-activate).

Although this is fairly straight forward, it can be annoying if you are someone who rapidly flashes your light off and back on (i.e. triggers mode switching if you do it under 1 sec). This means that momentary signaling is not possible with the light.

No PWM/Strobe

The X10 has just two constant output modes – no flashy, no blinky.

Testing Method:

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.

I have recently devised a method for converting my lightbox relative output values (ROV) to estimated Lumens. See my How to convert Selfbuilt's Lighbox values to Lumens thread for more info.

Throw/Output Summary Chart:

Effective November 2010, I have revised my summary tables to match with the current ANSI FL-1 standard for flashlight testing. Please see http://www.sliderule.ca/FL1.htm for a description of the terms used in these tables.

Let's start with a comparison to the 1x18650 lights:

Ok, the X10 is certainly in another league of output. Here is how it compares to the 2x18650 group of lights:

Max output on the X10 puts it squarely in the top-of-the-line class of XM-L lights. Throw is reasonable for the output, similar to the Fenix TK35 or JetBeam BC40.

Output/Runtime Comparison:

Note: My relative output scale is not linear for output across this range. Please see my Summary Tables above for lumen estimates.

Again, I'll start with the 1x18650 comparisons:

Runtime was bang on with the 4Sevens 1.8 hour estimate on Hi (i.e. 1hr 48 mins). On Lo, runtime was considerably less than the spec (i.e. 9 hours instead of 15). However, my lumen estimate was double that reported for the light (i.e. 200 lumens instead of 100 lumens).

A comment about the output level estimates – the X10 uses a partial regulation/step-down pattern over the run (likely a response to thermal management). Basically, the light seems to run mainly direct-drive, but with thermal regulation to step-down the light if it gets too hot. Under a cooling fan, using my crude conversion method (link above), I estimate the lumens to be ~770 at 3 mins into the run (i.e. ANSI FL-1 standard), but by 4.5 mins, it drops down to ~700 lumens. From 10-40 mins, it switches back and forth between ~670 and ~640 estimated lumens, before falling into a direct-drive pattern without thermal step-down for the rest of the run (until the protection circuit is tripped).

4Sevens thus seems to be conservatively using the lowest “regulated” level for lumen estimate for this light, even though it spends most of the time above this level. But again, I don’t have a calibrated integrating sphere to say for sure – this is a relative comparison based on lumen estimates of other lights.

Let's see how it compares to the 2x18650 class:

Output and runtime is pretty comparable to the 2x18650 lights (note I use only 2200mAh 18650s in my runtime testing above).

Potential Issues

Pressure switch/twisty only, no clicky switch. Mode switching design prevents signaling (i.e. flashing the tailcap jumps between output modes)

Beam has noticeable artifacts and tint shifting on my sample, but these are really only issues at close-range.

The light is not tightly regulated over its run, but seems to use some sort of thermal management to lower the output as necessary (which is actually a good thing, IMO). Note that all my runtimes are done under a cooling fan, which likely provides greater cooling than just hand-holding.

No primary battery option – 26650 Li-ion rechargeable only. Although in a pinch, you could use an 18650 IMR cell with something wrapped around it to create the appropriate thickness.

No wrist lanyard attachment point, the light cannot tailstand.

Preliminary Observations

The X10 is a solid light. It does what it does simply, with no fuss and no muss – blindingly bright Hi output, and a battery-sparing lower output.

Let's start with the output – the X10 is the brightest XM-L light I’ve seen running off a single cell. The X10 is brighter than my Thrunite Scorpion V2, which was my recent high-output champ on 1x18650. It's true the 26550 cell used here has higher capacity (and so can handle a drive current and discharge rate), but it's impressive that 4Sevens could drive the XM-L so high on 1x3.7V Li-ion source.

In fact, the X10 is solidly in the output class of my 2x18650 XM-L-based lights. The X10 matches the output, throw and runtime characteristics of this high output class.

The pressure switch is interesting, I haven’t seen one of these in awhile. Since there is no clicky, there are certainly no worries about handling the sort of current required here (i.e. the switch is just a press switch). The main gripe I have is the mode switching interface – whether you press on (momentary) or screw on (locked-on), flashing the tailcap switches modes. I would have preferred something like the old Surefire tactical two-stage pressure switch (i.e. Low comes on first, then Hi, as you press or screw tighter). But I guess Surefire has a patent on this, so it may not have been an option for 4Sevens.

In terms of the beam, you get a good balance here overall – a wider than typical spillbeam (good for near area examination), and a well-focused hotspot for maximum throw. But my sample is not the prettiest - there are some noticeable artifacts and tint shifting within the beam close-up. Still, these aren’t a problem at a distance (which is likely how you would use a high output light like this).

I don’t have other 26650-based lights to compare, but runtime seems very good for the output level and rated capacity of the cell. Again, the manufacturer specs seem conservative on Hi – 640 lumens was the lowest estimated output I saw over the thermally-managed first 40 mins or so (e.g. ANSI FL-1 estimate was ~770 in my case, but all my runtimes are done under a cooling fan). Runtime was bang on at 1.8 hours. On Low, I only got about 9 hours (instead of the rated 15), but my output estimate is twice that of the reported spec (i.e. 200 estimated lumens in my testing, compared to 100 lumen spec).

In terms of performance, the X10 is an impressive single-cell rechargeable light in the high-output XM-L class. It is certainly another compact option to consider in this class – especially if you are looking for as much power as possible in a small size.


X10 provided by 4Sevens for review.

To follow the online discussions for this review, please see the full review thread at CPF.

Return to the master review list (at flashlightreviews.ca).

For a list of all my CPF flashlight reviews in chronological order by battery type (direct link to CPF), please see here:
Candlepowerforums Threads by Selfbuilt

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Page last updated on August 21, 2011 - selfbuilt (at) sliderule (dot) ca (replace the "at" and "dot" labels with the appropriate symbol for e-mail)
All material © 1999, 2011 by Eric Marcotte.