[selfbuilt]

EagleTac M2C4 (P7) Review: New Version RUNTIMES, BEAMSHOTS, and more!

Reviewer's Note: The M2C4 (P7) was provided for review by EagleTac.

Warning: very pic heavy, as always

A few months back, I reviewed the initial release version of the M2XC4 (3xCree). Based on user feedback, EagleTac made a few modifications to the line. They have now sent me a sample from the second batch of the P7-emitter version, the M2C4.

M2C4 sepcifications:

• Seoul Z-Power P7 D-bin LED
• Up to 900 lumen output on Turbo
• Type-III Hard-Anodized Aluminum Construction
• Constant Current Regulation Output
• All-in-one Digital Rotary Switch with Off Position and Tactical Strobe, made of Re-enforced Polycarbonate with Smooth Rubber Coating
• Dual-Slot Loaded Battery Tray System, Re-enforced by Anodized Aluminum Construction and Stainless Steel Mounting Screws, fits CR123A and 18650
• Custom Fitting Silicon O-rings and Rubber O-rings for Water Resistance (IPX8 Standard)
• Gold Plated Copper Contacts for Superior Conductivity and Durability
• Type-III Hard-Anodized Aluminum Tail-Cap with Tail-Standing and Lanyard Attachment Ability
• Thermal Management Treatment for Continuous High Output
• Syntax I Anti-Reflector Coated and Hardened Shock-Mounted Window
• Removable Smooth Crenelated Stainless Steel Bezel
• Output Modes: Strobe > 900 lumens <> 420 lumens <> 170 lumens <> 40 lumens <> Off
• Runtimes (4x123A): Strobe <> 1.2hr <> 3.5hr <> 9.5 hr <> 45hr <> Off
• Runtimes (2x18650): Strobe <> 1.5hr <> 4.5hr <> 12.5 hr <> 55hr <> Off
• Included accessories: Paracord Lanyard with Position Lock, Rigid Nylon Holster with Adjustable Mounting for Different Belt Sizes, Spare O-ring

The first thing you likely want to know is how does it compare to the earlier M2XC4 build? Here are a few side-by-side pics (M2C4 with stock tailcap, M2XC4 with optional clicky switch):




M2C4: Length: 163mm, Width: 61mm (bezel), Weight: 351.7g (no battery)
M2XC4: Length 160mm, Width: 61mm (bezel), Weight: 395.8g (no battery)

As you can see, the M2C4 is ~3mm taller than the M2XC4, although it is lighter. I believe the second batch M2XC4s have come down a little in weight from the first batch reported above, but they are still heavier than the M2C4 due to the multi-well reflector and enhanced heatsink.

The second-batch version contains more labels, including bezel warnings to not look directly into the beam (), and a caution for hot surface. There is also a mark now on the bezel indicating where the Turbo mode is located, to be used in conjunction with a label on the grip ring. This is actually fairly useful, since the old version had no indication whatsoever, and it was pretty easy to overshoot and accidentally strobe yourself.

AFAIK, these new labels are present on all current shipping versions of the M2 line, including the M2XC4. My M2C4 also seems to be a glossier black, but that could just be normal variation in the type III anodizing.



The revised M2C4 package is similar to my original M2XC4, and comes with the standard set of extras, like extra o-rings, wrist lanyard, warranty card and manual, and a few extras like primary battery holders, and a good quality nylon case that fits the light well.

The main difference is that the optional clicky switch kit has been replaced with a full battery tray with the switch already installed, and a small jeweler's screwdriver to help you install the clicky cover. This is a considerable improvement, since the old switch kit could be difficult to install on an existing battery tray.



Here are some additional detailed battery tray pics from my original M2XC4 review:





18650 batteries fit fairly snugly inside the carrier, but I recommend you use the included primary cell holder tubes for CR123A (prevents rattle, and holds everything together well).

As shown in my original M2XC4 review, the battery/body tube is attached to the tail-plate and head region base by two series of four small screws.




Note the presence of o-rings on each of four screws (these are needed for waterproofness, given the design). Here is the tail region, in stock form:




The standard tailcap is a different design than the head region, and the main o-ring appears to be sufficient to provide waterproofness (thus no o-rings on these screws). When switching to the clicky-switch version, pay close attention to how you seat the main o-ring on the clicky switch module. If you are not careful, the o-ring will bulge inward and reduce waterproofness.

The M2C4 uses heavily textured reflector to help smooth out the Seoul P7 beam pattern.



You might think I hadn't managed to focus the camera too well on the emitter in the pic above – but it is in fact well focused. EagleTac appears to have slightly sanded the surface of the P7 emitter dome, likely to help reduce the dreaded "donut" effect produced by quad-die emitters. This makes the emitter look a little fuzzy in the picture above (and in real life).

UPDATE AUGUST 13, 2009: It appears my supposition was correct - EagleTac confirms that the P7 dome in the M2C4 has been "slightly polished" to improve the beam. They have apparently tested various brands/grit of sand paper, and have chosen one that they feel achieves the best result.

In contrast, the 3xCree M2X-series lights use a reflector with 3 partially overlapping wells for each of the emitters. From my original M2XC4 review:



Here are some comparison beamshots, taken on Max on 2x18650 AW protected Li-ion. Distance is about 0.5 meters from a white wall.






The sanding trick does seem to have helped reduce the donut-hole effect somewhat. Note that like most P7-based lights, the spillbeam is fairly wide on the M2C4. In contrast, the 3xCree M2XC4 has the typical “daisy” flower appearance customary to this reflector design.

Here are some outdoor shots focused on a point ~30 feet from the lights. For comparison to the older lights, please note that I have since planted a tree in my back yard.









And here are some lower exposures to better show you the hotspots:









Overall output of the M2C4 on Turbo is among the highest of this class. Throw is lower than some of the competition, but then again so is the dreaded "donut" hole (common to P7/M-CE emitters). Still, the Tiablo ACE-G still remains the donut-hole-free king.

User Interface

Key to using the light is the rotary grip ring at the base of the head. This is made of polycarbonate (i.e. plastic) with a fairly “grippy” feel. The ring on my second batch M2C4 seems stiffer than my earlier M2XC4, but I don't know if this is simply natural variability or a design change.

The ring slides evenly over a ~110 degree arc, which runs in sequence as you turn clockwise from Standby/Off, through Lo, Med, Hi, Turbo, and Strobe (measured at 8 Hz on both my samples). This rotary dial controls mode switching by the presence of a small embedded magnet. As it passes over various control points on the circuit, it triggers the different modes.

The output mode ranges don't seem to be evenly spaced – I illustrated this graphically in my M2XC4 review, and repeat the image below since my M2C4 seems similar. Starting at the 12 o’clock position and turning to the right (clockwise if holding the light and pointing away from you).



There are no detents to tell you when you have a reached a mode – the ring turns smoothly and continuously. The new bezel/ring marks for Turbo mode are helpful in preventing accidental strobing, although I personally prefer the feel of actual detents (i.e. like the JetBeam Raptor RRT-2 or NiteCore SR-3).

With the standard flat tailcap installed, I find this ring works well only in traditional flashlight carry mode (i.e. underhand). In overhand “tactical” stance, it is hard to control the ring. But with the forward clicky kit installed, you can set the ring to your desired output mode and simply control on/off by a thumb-press in tactical overhand stance.



The M2C4 is not as top-heavy as the original 3xCree M2XC4, and I do find it more comfortable to carry around. I still prefer to carry it underhanded without the clicky installed, but your taste may vary.

Note that with all rotary dial interfaces, the light is always drawing power when fully connected (even if the ring is in "Off" mode). "Off" in this context is more of a standby mode. To insure there is no persistent current drain, you need to unscrew the head until no light can be produced, or install the clicky-switch tray and leave the light clicked off. These are the only two ways to break the current path. Failure to do so will mean your batteries will drain to zero within a few months of standby storage.

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.

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 will be my standard way to present throw on these types of lights from now on. The beams don't really have a chance to fully converge until typically several meters out

Some of the other lights take a couple of minutes to settle into their regulated output state (i.e. their initial output is higher, but not for long). As such, all my output and throw numbers are taken after 2 mins of continuous runtime (on 2x18650 AW Protected cells).

Throw/Output Summary Chart:



The ceiling bounce and lightbox tests confirm that the second batch M2C4 has slightly more output than my original M2XC4. I believe the early edition M2C4s had lower max output, but this was increased on subsequent batches.

Throw is definitely lower, similar to P7/M-CE Lumapower MVP P7 and Tiablo ACE-G.

Output/Runtime Comparison

All 18650 runtimes were done on AW protected cells (2200mAh).



As in the case of the M2XC4, the M2C4 regulation pattern is excellent on all batteries, perfectly flat at all levels initially. Output levels and runtime appear to be very close to the M2XC4 (see detailed comparisons below).





I am impressed by the performance of the constant-current circuits in these lights – both the M2C4 and M2XC4 produced excellent runtimes at well-spaced (and comparable) output levels. The M2-series lights particularly distinguish themselves on Med and Lo modes – see how long they run compared to the PWM-based competition at these levels.

Sorry, I haven't done any CR123A runs on the M2C4, but based on the performance above, I expect the M2XC4 results should be a good guide for you:



Potential Issues

There are no significant new issues from the original M2XC4 release, and a number of previous issues have been addressed. Remaining concerns include:

Light design requires use of a battery carrier. The new addition of a secondary carrier with clicky switch pre-installed is a welcomed bonus, given previous difficulties in installing the switch.

The original M2-series lights had waterproofing concerns, due to the large number of screws involved. Inclusion of individual o-rings in the head portion of the light seems to have resolved most of these. I recommend users still check to insure the screws remain tightly in place, as they may loosen with time.

The lack of detents on the rotary dial can make it difficult to rapidly select the level you want without “overshooting." However, the addition of labels for the Turbo mode helps prevent accidental strobing incidents.

All rotary dial lights draw power in the dial "off" position (which should more accurately be termed a standby mode). You can lock-out the light by unscrewing the head until the light shuts off, or install the clicky switch and keep it in the clicked off position.

Preliminary Observations

I have already covered a lot of the ground work on the pros and cons of this build in my original M2XC4 review, so I will focus here on what’s new and/or changed in this second batch M2C4.

The M2-series build changes are relatively minor, and reflect an ongoing tweaking of the existing design (e.g. Turbo indicator on the ring, extra battery tray with clicky switch installed, etc). A few things I don’t necessarily consider improvements (i.e. the new warning label advising you not to stare into the light is a bit much ). And I would still like to see an overhaul of some design aspects – top of my list would be detents on the control ring and solid construction between the battery tube and head-connecting region (i.e. no more screws there). But on the whole, I’m glad to see the continued care and attention the build is getting.

I don’t have a first generation M2C4 to compare, but I can tell from other commentary here that this second batch of lights must be driven at a higher level (or have a higher output P7 bin). Overall output of my M2C4 is just a touch higher than the 3xCree version, making this light the current output champ in my multi-die/multi-emitter collection.

The beam pattern is certainly acceptable for a P7 die, with less of a donut-hole than typical. But I’m not really a fan of emitter dome sanding (i.e. too variable a procedure, hard to predict how it will alter the beam). It’s clearly possible to do a lot simply with a good reflector design (e.g. Tiablo ACE-G).

Output/runtime performance of the M2C4 was certainly excellent. It is remarkable how close output levels and runtime are between the P7 and 3xCree cool-white models. EagleTac has certainly managed to achieve an excellent balance there – good job.

The lower head weight of the M2C4 is also a definite plus in my mind. Although it is not a huge difference, it is enough to give the M2C4 a definite “hand-feel” edge over the M2XC4 for me.

At the end of the day, I think I still prefer the M2XC4 for the greater throw and narrower/brighter spillbeam. But it is really all about choice and selection for consumers. I am glad to see that EagleTac offers the M2C4 model as part of their line up, and that they continue to "tweak" the design.