Convoy S2+ measurements (7135*8 3B)

The Convoy S2+ is a cheap 18650 light which is often recommended to new members on forums and reddit and for a good reason. For about 15 euros / dollars, it offers exceptional finish and good performance. The machining is excellent and threads feel very smooth.

Manufacturer specifications

* Battery type: 1x 18650 (protected or unprotected)
* LED: Cree XM-L2 (5 options for tint)
* Body material: Aluminum
* Waterproof: Yes
* Lens: Glass
* Reflector: Orange peel
* Protection: Low voltage warning (2.9-3.1 V), reverse polarity
* Mode memory: Yes
* Length: 118 mm
* Width: 24,1 mm
* Price: 15-20 euros/dollars





When ordered from a trusted source (I got mine from Convoy's Aliexpress shop), it comes in a sturdy white cardboard box with foam cutouts for the light and a lanyard with a keyring attachment. Unfortunately there's no pocket clip included but it is available as an optional extra for under 1 dollar in Convoy's shop (gttp://www.aliexpress.com/store/product/universal-clip-suitable-for-S2-S2-M1-C8/330416_32579921654.html). The clip also fits on the S2, M1 and C8 flashlights.



The S2+ accepts both protected and unprotected 18650 batteries, button tops or flat. All of my batteries except for a 18,97 mm thick Keeppower 3500 mAh fit in to the tube just fine and there was no rattle. There's also a 18350 battery tube available for a couple of bucks.



The light is customizable in a couple of ways during the order process. In addition to several colors (black, grey, red, green, blue) you can choose the 7135 driver current between 1050, 1400, 2100 and 2800 mA. There is also a choice between five different tints for the Cree XM-L2 emitter:

* U2-1A (6500-7000 K)
* T6-3B (5000-5200 K)
* T6-4C (4300-4500 K)
* T5-5B (4000-4200 K)
* T4-7A (3000-3200 K)

The modes are also customizable and the manufacturer offers four choices:

* 5% low - 30% mid - 100% high - SOS - strobe
* 5% low - 30% mid - 100% high
* 10% low - 100% high
* 10% low - 100% high - strobe

If you choose a driver with the special SOS or strobe modes, you can switch between two groups of modes, one of which doesn't have the special modes and one with them. The switch between groups is done by switching the light to low and switching it off after 5 seconds when you see the flashlight blink.



The steel tail switch has a sturdy feel and a reassuring click to it. Changing between modes is done by a tap on the tail switch. Full press turns the light on and off.

The light tested here is the 7135*8 (2800 mA) driver variant with 3 modes (5/30/100 %) and a Cree XM-L2 T6 3B emitter. 3B is supposed to be 5000-5200 K, but my sample was quite far off at 4540 K (maybe a 4C by accident?).

The tint is skewed towards green, but it's not that bad without having an actual neutral white to compare it to. Color temperature doesn't vary too much in different modes. Color rendering is average with a CRI of 72.

Some retailers claim 1000 lumens for the S2+. This is not accurate and I measured just shy of 700 out the front in my diy integrating sphere. There's also no moonlight mode and 40 lumens on the lowest level might be too bright to use in absolute darkness. If you want more range in the output and a direct drive turbo, I recommend checking the Astrolux S1 (http://www.candlepowerforums.com/vb/showthread.php?414781-Astrolux-S1-measurements), which is about double the price of the Convoy S2+.


18650 battery, Convoy S2+, Astrolux S1, Eagletac D25LC2, Zebralight H600Fd III

Measurements

Please note: lumen measurements are only rough estimates
My diy 30 cm integrating styrofoam sphere has been calibrated using a Fenix E05 on high with manufacturer's claim of 85 lumens. Verified with an Olight S10 that has been measured with a Labsphere FS2 integrating sphere by valostore.fi. Results may be more inaccurate with especially throwy or floody lights.

For spectral information and CRI calculations I have an X-rite i1Pro spectrophotometer with HCFR for the plot and ArgyllCMS spotread.exe for the data. For runtime tests I use spotread.exe with a custom script and a i1Display Pro because it doesn't require calibration every 30 minutes like the i1Pro.

Explanation of abbreviations

CCT = correlated color temperature, higher temperature means cooler (bluish)
CRI (Ra) = color rendering index consisting of 8 different colors (R1-R8), max value 100
CRI (R9) = color rendering index with deep red, usually difficult for led based light sources, max value 100
TLCI = television lighting consistency index, max value 100
CQS (Qa) = Proposed replacement for CRI, RMS average of 15 color samples
CRI2012 (Ra,2012) = Another proposed replacement for CRI, consists of 17 color samples
MCRI = Color rendering index based on the memory of colors or 9 familiar objects
x,y = coordinates on a CIE 1931 chart





Spectral distribution


Color rendering (High)
Read more on color rendering indices here: http://www.candlepowerforums.com/vb...CRI-vs-alternatives-with-measurement-examples


Tint

Different brightness modes


Tint towards the edge of the spill

Beam and beam angles




The beam angle is 69° with a hotspot of 19°. The hotspot has a greenish tint while the spill is neutral cool white.

PWM

PWM is used on all modes other than high. The high switching frequency (4540 Hz) and low amplitude makes it only visible on camera, not to the naked eye. There is slight audible whine on medium when your ear is less than a foot away from the light. Not a deal breaker.


Low


Medium


High, no PWM

Runtime (High and Medium)


The light is regulated on high until about 30 minutes after which the output starts to decline. With an Eagtac 3500 mAh battery I was able to get a runtime of 1 hour 28 minutes on high and 5 hours 27 minutes on medium until the low voltage protection of the light kicked in. I measured the tailcap current at 2,7 amps on high, 0,8 on medium and 0,1 on low with a fully charged battery. There is no stepdown on high.

Temperature

In room temperature and on high the S2+ with the most powerful driver (71358) gets uncomfortable to hold after about 6 minutes when the battery tube reaches 50°C. Of course the temps will be lower if you hold it because your hand acts as a heat sink. The head reaches 65°C at 7 minutes.

Thermal image @ 7 minutes.

What a great review!

maukka said:

The S2+ accepts both protected and unprotected 18650 batteries, button tops or flat. All of my batteries except for a 18,97 mm thick Keeppower 3500 mAh fit in to the tube just fine and there was no rattle.

Click to expand...

What was the longest battery that you were able to use? I was interested in the S2+ until I saw one seller posted that the maximum supported battery length was 67 mm. My protected cells all seem to be 68.5 mm or longer and I'd rather not have to get unprotected or shorter cells for one light.

Your review was just... "brilliant." Thank you.

Do you think there would be enough room to add a heat sink and do you think this would work with an XP-L HI MOD?

Great review! Thank you

D6859 said:

Great review! Thank you

Click to expand...

+1

Thanks for another great review, I seem to order all the lights that you reviewed (but this one I actually ordered before your review )
It would be interesting to see comparison between the different drivers (7135*4 and 7135*8 for example) because I saw some discussions on BLF forums that the lumens output is not as different as it would be expected from the different currents drawn.

Thank you very much for doing this :thumbsup:

I love having lots of hard data like this for my lights, so I've added a link to your review in the original post of my Convoy light options thread. My thread contains LED option comparison tables and Convoy tint images, so I think the people who use them will find your data very helpful.

Moving this to Flashlight Reviews

maukka said:

...
The light tested here is the 7135*8 (2800 mA) driver variant with 3 modes (5/30/100 %) and a Cree XM-L2 T6 3B emitter. 3B is supposed to be 5000-5200 K, but my sample was quite far off at 4540 K (maybe a 4C by accident?).

The tint is skewed towards green, but it's not that bad without having an actual neutral white to compare it to. Color temperature doesn't vary too much in different modes. Color rendering is average with a CRI of 72.

Some retailers claim 1000 lumens for the S2+. This is not accurate and I measured just shy of 700 out the front in my diy integrating sphere..

Click to expand...

For what it is worth I just took delivery on the 18350 version from Banggood. My testing confirms that something is a little off with the Kelvin specs on these lights, on the XML2-U2 in my sample, just as maukka noticed the actual temp is more like the next emitter down the ladder, in this case down to a T6-3B (5000-5200 K).. I do not notice any "green" in my sample. But the output of the lamp is quite good at 857 on HI. My sphere is home made and has been testing against dozens of known good samples and the math has been corrected (a la selfbuilt conversion math system..), so I am very confident in the numbers:
-----------(lo) (med) (hi)
Lumen ----45 379 857 (caveat emptor: my Lux measurements normalized to 1sqMeter )
Kelvin --5020 5030 5047 (see my post 2 down from here for details on the reliability of this measurement)
Tested w/: Basen, 18350 High Drain (12A) Charged to 4.17V

Banggood Grey Convoy S2+18350 XML2-U2-1A, 7135x8, Delivery of Sample on: 11-1-2016

With my new sphere I get 785 lumens (@30 sec) from the same blue S2+ tested here. Although now with a Samsung 30Q cell and not the low current Eagtac like previously.

Also, I also measured the output of a Grey S2+ with a 1B cool white emitter and 6x7135 from Gearbest. It read 665 lumens at 30 sec with a 30Q. So if linear, it should go up to 887 lm with 8x7135. That's in line with your measurement of 857 lumens.

maukka said:

... That's in line with your measurement of 857 lumens.

Click to expand...

Yes,.. results I get measuring output should be OK, but it is the color temp I have no proper instrumentation, so really I should edit my post and just delete the Kelvin data. I have 2 more samples of these lights in transit to me now. One from the Simon/AliExpress site and other from Gearbest. When they arrive I will test them and see what the results are. For Kelvin, I am using iPhone sensors and software and that is just not reliable, it is effected by PWM, peak intensity, and other factors. Sometimes it is reasonably in the ballpark (I believe in this case example it is OK, as the result is strongly corroborated by careful eye-ball comparisons to known good samples..), but the iphone instruments behavior is anomalous and not reliable.