SUNWAYLED M40C Review (MC-E 2x18650): RUNTIMES, BEAMSHOTS, and more!

Originally posted: July 14, 2010
Last revised: March 12, 2011

Reviewer's Note: The pre-release M40C was provided for review by SUNWAYLED. Please see their website or batteryjunction for more info.

Warning: pic heavy, as usual

Manufacturer Specifications: (taken from the SUNWAYLED website). The M40C is part of a new series of lights launched by SUNWAYLED. My review of their M10R and M20C are now up.

Note that my sample was a pre-release version, so I don’t know what the final shipping packaging looks like. Circuit performance should be unchanged on the shipping versions, though.

Taken in isolation, the initial impression you might have is that this light looks remarkably like the Eagletac M2 series lights. But there are a number of significant differences. The first of these is size:

From left to right: SUNWAYLED M40C, Eagletac M2C4, Eagletac M2XC4, Olight M30 (no extender).

M40C: Weight: 258.5g (no battery), Width (bezel) 57.1mm, length 156mm
M2C4: Weight: 351.7g (no battery), Width: 61mm (bezel), Length: 163mm.
M2XC4: Weight: 395.8g (no battery), Width: 61mm (bezel), Length 160mm.

The M40C is only ~2/3-3/4 the overall weight of the M2-series lights, and a good 1-2 centimeter shorter (the above M2 lengths are based on the flat tailcap – the clicky adds additional length). Most the height difference seems to come from the lower profile head in the M40C (even though bezel width is not that much smaller).

The M40C is definitely a more compact version of the side-by-side 2x18650 battery arrangement.

The control ring has good feel, with noticeable detents at every level (something the M2-series lights lacked). Note there are no identifying labels on the control ring on the M40C. I would describe the feel as very similar to JetBeam RRT-series lights. For that matter, I would describe the overall styling as very JetBeam-like as well. I am not sure what material the control ring is made of, but the feel and anodizing color are an exact match to the rest of the aluminum frame.

In addition, there is also a small red LED located just under the bezel (shown above). This is the low battery indicator (scroll down for a discussion of the UI).

The light comes equipped with MC-E emitter inside a relatively steep reflector. Along the outside of the reflector are a dozen small 5mm LED, 6 in blue and 6 in red. Below are some close-ups, focused on either the MC-E or 5mm LEDs, and a comparison to the Eagletac M2C4.

As you can see, the relative surface area of the reflector for the main MC-E emitter is greatly reduced on the M40C, compared to the M2C4.

Unlike the stock photo shown on the SUNWAYLED website, the red and blue 5mm LEDs are visibly different even when the light is off. This is a bit unusual, and gives the front end of the light something of a bejeweled appearance. Here they are turned on.

Note that the 5mm LEDs are not very high-powered, and are really to be used as alternative lighting under low-level conditions (e.g. map reading, etc.).

I don’t know what other accessories the shipping lights will come with, but a reasonable quality wrist lanyard was included on my sample.

The low-profile rear on/off switch is a reverse clicky, and has a good feel (short traverse to turn on/off, not as stiff as my M10R forward clicky). The light can still tailstand thanks to the surrounding ring (unlike M2-series lights, where you loose tailstanding with the clicky switch). I found the switch easy to access.

The switch retaining ring is held in place by 4 hex screws. The impression given is of a good watertight seal.

Now this is nice – the head-region of the battery tube is a solid piece of aluminum. On the earlier Eagletac M2-series lights, four additional screws and an extra o-ring were needed to hold the front-end of the light together (and the screws had a tendency to loosen up). This is a much better design to insure waterproofness.

Screw threads are very high quality – square-cut machinist threads, fully anodized at both ends for lock-out. There are also a reasonable number of threads – at least 4 full turns (unlike the M10R, which only had 2 full turns). The o-ring was a bit thick on my sample, but I understand shipping versions should have a revised one that fits snuggly but not over-tight.

The battery compartment is reminiscent of the M2-series lights, but is somewhat more compact. The clicky switch is also built-in. Thanks to the carrier springs at both ends, flat-top high-capacity protected cells will work in the light.

Fit and finish on my sample is simply excellent. I really like the color – a rich, dark grey – very similar to some of the earlier NiteCore lights. The type III hard anodizing seems top notch, among the best I’ve seen (absolutely no flaws or chips, and seems thicker than typical). Lettering is bright and clear, sharp and easy to read.

I must say, the overall build seems very high on this light – higher than the earlier M2-series, to be honest. This doesn’t seem like a “new” light at all – rather, it feels like a compact extension and revision of the Eagletac M2-series lights, with some JetBeam-like styling and features thrown in.


And now for the white wall hunting. Here are some up-close shots comparing to the Eagletac M2C4, about 0.5 meters from a white wall (all lights on 2xAW protected 18650).

As expected, the M40C beam profile is very similar to the Seoul P7-equipped M2C4, but with a somewhat less focused hotspot (likely due to the smaller overall reflector). Spillbeam is also a bit narrower (again, likely for the same reason). Scroll down for output/throw measures.

I’ve recently moved, so will need to start re-doing my outdoor beamshots. For now, here are a couple of comparison shots of the M40C and Eagletac M2C4 in my new backyard. Distance to the base of the tree is about ~7 meters (~23 feet). Sorry the M40C shots got a little blurred.

Again, the M2C4 seems to have a slightly wider spillbeam and a slightly more focused hotspot. But the M40C seems brighter overall for the area it illuminates.

UPDATE: Some additional long-distance beamshots, to show you how the light compares to others in its class.

Please see my recent 100-yard Outdoor Beamshot review for more details (and additional lights).

Scroll down for some throw and output numbers.

Here are a couple of beamshots to show you the red and blue emitters. Up-close, there is a bit of a “daisy-flower” appearance to the spill, but this isn’t really distracting. Note the pics below are taken at different exposures, due to the lower output of the red LEDs.

User Interface

On/off is controlled by the tailcap clicky (reverse clicky). Mode switching is controlled entirely by the magnetic control ring in the head.

Basically, this will seem familiar to anyone who has used a magnetic control ring light (e.g. JetBeam RRT-series, Eagletac M2C4, NiteCore SR3). There are five defined levels the ring can be turned to – and you feel the resistance change substantially when it falls into place (these are typically called “detents”). The M40C control ring feels (and looks) most like the JetBeam RRT-series control rings.

The five control ring levels on the M40C are Lo – Med – Hi – Blue - Red, arranged clockwise if you have the light in hand pointed away from you. The total traverse of the ring is ~1/2 the circumference of the light, and you can switch back and forth with ease one-handed. Note there is no “standby” mode – you turn the light on or off by the tailcap clicky only. There is thus no parasitic drain to worry about.

There is a small LED just below the bezel that will glow red as the cells near exhaustion. After a few mins of continuous output, this LED will begin flashing (don't worry, it isn't overly bright). If you don’t power down or switch to a lower output within a few more mins, the light will fall out of regulation or the built-in battery protection circuits will be tripped. Scroll down to the runtimes section for more info.

There is no sign of PWM flicker detectable by eye or my sound-card oscilloscope on any level. SUNWAYLED reports the light is current-controlled, and my runtime data support that claim (scroll down for details).

Testing Method: All my output numbers are relative for my home-made light box setup, a la Quickbeam's flashlight reviews 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.

Throw values are the square-root of lux measurements taken at 5 meters from the lens, using a light meter, and then extrapolated back to estimate values for 1 meter. This is my standard way to present throw on these types of high output lights. The beams don't really have a chance to fully converge until typically several meters out.

Throw/Output Summary Chart:

As you can see, overall output of the M40C is comparable to the Eagletac M2-series lights (which are among the most heavily-driven of the multi-emitter class). Lo mode is lower on the M40C than typical for this class. Throw is also at the low end for the class, similar to the Olight M30.

Output/Runtime Comparison

Note: Effective January 2010, all CR123A runtimes are now performed solely on Titanium Innovations batteries. You can compare the generally excellent performance of these CR123A cells relative to the Duracell/Surefire cells used in all my earlier reviews here. I have marked all the new runtimes of lights with Titanium Innovations CR123As on the graphs with an "*".

Perfectly flat regulation on Med and Hi (Lo not tested, but I expect the same there).

BTW, the low-voltage sensor works well. The small red LED below the bezel lights up when the batteries are running low (but still in full output regulation). After a couple of minutes, this red light begins flashing. If you don’t power off or switch to a lower level, the protected batteries will cut-off after a few more mins.

On primary CR123A, the red warning light works the same way. But there is one quirk: when the warning light finally shuts off – and the batteries drop out of regulation - the main light begins flashing/strobing continuously. Not sure why this happens on CR123A, but I would prefer a slow gradual drop-off once out of regulation. Still, you do get plenty of advance warning with the warning light.

How does it stack up to the competition?

The runtime patterns are virtually identical to the current-controlled Eagletac M2C4 on Med and Turbo. It looks like a remarkably similar circuit is being used (but one with a much lower Lo mode on the M40C). This is clearly one of the best performing MC-E/P7 lights I’ve tested at these levels (both for regulation pattern and runtime).

Potential Issues

Frankly, I have little to say here. The M40C seems like a more compact version of the Eagletac M2-series lights, with additional features and many of the early limitations/issues corrected.

The is no slow drop-off in output on 4xCR123A – the main light starts flashing immediately once the cells fall out of regulation. But you do have at least several minutes of warning before this happens, thanks to the low battery indicator LED.

Preliminary Observations

As with the M10R reviewed recently, the M40C demonstrates that SUNWAYLED has previous experience in making flashlights. SUNWAYLED confirms that their designer and factory have previous OEM experience for other makers (but they don’t want to impact those brands by naming them).

The point here is that the M40C does not seem to me to be a “copy” of the Eagletac M2-series lights, or anyone else. Rather, it seems more like a revised “second generation” with new features and styling – some of which seem similar to other brands, and some of which seem completely novel.

Simply put, the M40C is a well-thought-out and executed flashlight. The care and attention to detail in the fit and finish are top-notch – this is one of the best anodizing jobs I’ve seen. The ergonomics of the light are good, and I like the more compact size and shape (while still feeling very sturdy). I’m frankly amazed they were able to integrate a clicky switch in this build (while maintaining tail-standing).

The interface is thoughtful – I for one am glad to be done with strobe (but I know others here like it ). However, I think it would make more sense for red and blue to be located next to the Lo white in the sequence, instead of after the Max white mode (i.e. the colored output is very low anyway). Also, the red and blue LEDs are visibly colored even when off, which may not be everyone’s stylistic choice (I would personally prefer colorless 5mm LEDs here).

Beam profile on the main MC-E emitter is very nice – probably one of the “floodiest” high-output lights in my collection. The spacing of output modes is good in my opinion – Lo is lower than typical, but this makes it more useful for navigating more cramped environments (e.g. lighting up indoors), where a floodier light is handy. And you can’t beat the regulation or runtime – both are simply excellent.

The low battery warning LED sensor worked well in my testing – this is an innovation I would like to see other makers duplicate. At all levels on all batteries, you get plenty of warning that the light is about fall out of regulation – at least several mins of solid red, followed by several mins of slow flashing red. If you switch to a lower output, you may be to get this warning light to shut-off – but it will likely re-illuminate soon, as the batteries continue to deplete.

Simply put, the M40C shows some definite upgrades and improvements over earlier lights. While these may not be enough to make you consider “upgrading”, the SUNWAYLED M40C definitely warrants careful consideration if you are in the market for a compact high-output light.

Based on this strong initial showing, I am looking forward to testing the other lights SUNWAYLED has in the works.

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

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