# Review of OLight M31 Triton



## HKJ (Sep 19, 2010)

[SIZE=+3]OLight M31 Triton[/SIZE]


















OLight was the first to use the Luminus leds in a production light (M20 Ti) and have continue making high power lights with it. M31 is a tactical light with high light output and very good throw. It uses the same user interface as M20 and M21 with a on/off tail switch and mode change requires a twist loose, twist tight of the head. The modes are also the same: 3 brightness settings and a strobe. The light is made of aluminum with hard-anodized (Type 3) finish. 









The light is supplied in a plastic case together with a few accessories.






The contents of the box are: The light with extender, a holster, a battery magazine for 3xCR123, 2 spare o-rings and the manual.









From the front the big smooth reflector with the SST-50 in the center can be seen.






Just behind the reflector the light has a heatsink, but according to the documentation it is a bit small for the light (The documentation warns against running to long time in high). The light can run more than 10 minutes before it gets really hot, using it in cold weather or stormy weather will increase the cooling significant.












Between the head and the body of the light, is the connection used for the twist of the head part of the user interface. This connection only has one o-ring. The connection to the battery plus pole has a spring this makes it possible to use flattop batteries.







On the body of the light is square knurling, this knurling is rounded.









On the body is mounted a optional clip. When using the light with 3xCR123 or 2x18500 batteries, it has a good placement, but with 4xCR123 or 2x18650 it is on the middle of the light. 






The light includes a battery tube, that can be preloaded with 3xCR123 batteries, making it fast to replace the batteries. This can only be used for the short configuration. The batteries fits tight in the tube, making it slow to reload a battery tube.
The light can easily use CR123 batteries without the tube!









The rear end of the body has two o-rings, both the battery tube and the extender tube is equipped with the two o-rings.









In the tail the spring is hidden beneath a cap. The switch is a forward switch, which is placed below the teeth on the tail, making it possible for the light to tail stand on plane surfaces.






This is how far I could take the light apart without tools.









The light includes a holster that can be used with both the short and long configuration of the light.


This light is a powerful thrower that is designed to supplement the M20/M21/M30 series of light with a super thrower. The light does that, but you have to watch the battery configuration, 3xCR123 is not really a good option for this light, but with two 18650 batteries the light works very well.



[SIZE=+2]Technical specification and measurements[/SIZE]










The light can be used with 3xCR123, 4xCR123 and 2x18650 batteries (2x18500 is also a possibility).

Measured size and weight:
Length: short: 212 mm, long: 246 mm
Diameter: 24 to 63 mm
Weight: 3xCR123: 307.6 gram, 4xCR123: 341.2 gram, 2x18650: 368.9 gram

The light uses a Luminus SST-50 led






In the above table I have used 2600mAh 18650 batteries for measuring and estimating runtime. The specified level spacing matches nicely up with the measured brightness.






A voltage scan shows that the light has very good regulation down to around 6 volt. The driver is rather hard on CR123 batteries around 6 volt with about 3 ampere current draw.






The light has a very fine regulation on 18650 batteries and also a good runtime, but 3xCR123 batteries do not really work in the light, at least not on high.







The light has a strobe of 9.7 Hz with 50% duty cycle, the strobe is slightly brighter than the usual high level (the green line).



[SIZE=+2]Comparison to other Flashlights[/SIZE]

Fenix TK40, Fenix TK45, OLight M31











JetBeam RRT-3, JetBeam M2S, ThruNite Catapult V2











For the full comparison to other lights with graphs and beamshots see here.


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## dhouseng (Sep 19, 2010)

Thanks HKJ for your review on this light!


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## SCpooh (Sep 19, 2010)

Great job HKJ, as usual.:goodjob:


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## NCT1 (Sep 19, 2010)

Great review, I've been waiting on this!!!


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## HIDblue (Sep 19, 2010)

Great review and outstanding photos! :thumbsup: The M31 looks like a great thrower.


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## jwyj (Sep 20, 2010)

From the photos, the M31 looks like the best thrower of the lot. Is it true?


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## HKJ (Sep 20, 2010)

jwyj said:


> From the photos, the M31 looks like the best thrower of the lot. Is it true?



if you follow the link to the full beamshot, you can see that there are light with better throw. 
The M31 is the best thrower for its size, but the difference between M31, Cat V2, RRT-3 is very small and I doubt you can see the difference, except when using both lights at the same time.


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## lew187 (Sep 20, 2010)

m31 has the sliiightly brighter hotspot. Cat v2 has slightly more light arround the spot. thats it. I have both. The M31 is a nice light of course. Easy to carry. Nice operating. F... strobe. Always have to pass strobe if i wanne change max to low. dammit.:scowl:


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## dhouseng (Sep 21, 2010)

I just got my M31. I turned it on high and after a minute it got quite warm at the head. 
The manual says use high mode sparingly to avoid damage. So actually how long should "sparingly" be? Is 5 minutes okay?


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## HKJ (Sep 21, 2010)

dhouseng said:


> I just got my M31. I turned it on high and after a minute it got quite warm at the head.
> The manual says use high mode sparingly to avoid damage. So actually how long should "sparingly" be? Is 5 minutes okay?



It is difficult to say a specific time, because it depends on cooling (Hand or airflow) and ambient temperature. It is no problem just because you can feel it is a bit warm, it has to be really hot before there are any risk for the led. During the review I did run the light for 10 minutes with only a hand as cooling and I did run it for more than an hour with a fan as cooling.


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## easilyled (Sep 21, 2010)

I didn't see you mention using 2 18500s in the shorter format. I am assuming that regulation would be very good with these, like it is for 2 18650s, 
with the runtime being shorter?


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## HKJ (Sep 21, 2010)

easilyled said:


> I didn't see you mention using 2 18500s in the shorter format. I am assuming that regulation would be very good with these, like it is for 2 18650s,
> with the runtime being shorter?



I did not run any test with 2x18500, but from the voltage scan I can see that it will have a rather high current drain (2C) and that the light goes out of regulation at 6 volt, this might mean that the light drops out of regulation a little bit before the batteries are empty.
The runtime will probably be only about 1/2 of 18650 batteries: 1500 mAh with 2C load contra 2600-2900 mAh with 1C load.


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## Ray_of_Light (Sep 21, 2010)

Thank you for your clear review.

Anthony


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## candle lamp (Sep 21, 2010)

Thank you for your excellent review.
Could you explain what the Measured & Estimated mean in the following table ? 
How do you get the values ?






Thanks,


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## HKJ (Sep 21, 2010)

candle lamp said:


> Thank you for your excellent review.
> Could you explain what the Measured & Estimated mean in the following table ?
> How do you get the values ?
> 
> ...



Measured are measured with a meter, but I always scale lux values (Brightness) to a relative value, because the actual lux measurement does not have any meaning for other people.

Estimated values are values estimated from the measured values.

Estimated Lumen is estimated based on the specified lumen at max. brightness and then scaled with the lux measurements for the low brightness settings, this gives a good idea about how the settings match the specified settings (In the above table I have multiplied brightness with 8).

Estimated runtime is calculated from the measured current draw, this gives a rough idea about the runtime for all modes. For this light I am using 2600mAh batteries, i.e. the estimated runtime is 2600mAh/123mA hours for low mode.

All values in the table are rounded values, i.e. a low brightness of 8 can be anywhere from 7.5 to 8.49


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## candle lamp (Sep 21, 2010)

HKJ,
Many thanks for your detailed explanation. I've understood what you meant.


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## selfbuilt (Sep 21, 2010)

Thanks for the detailed review HKJ, excellent work as always. :thumbsup:



HKJ said:


> I did not run any test with 2x18500, but from the voltage scan I can see that it will have a rather high current drain (2C) and that the light goes out of regulation at 6 volt, this might mean that the light drops out of regulation a little bit before the batteries are empty.
> The runtime will probably be only about 1/2 of 18650 batteries: 1500 mAh with 2C load contra 2600-2900 mAh with 1C load.


That's why I like your current-volt graphs, useful for pulling out relationships. 

It does seem like the drain would be a bit heavy for typical 18500 batteries. A pity, as I quite like the smaller size in lights that handle them (e.g. Olight M30 and JetBeam M1X - where both lights last for over an hour on 2x18500).


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## SCpooh (Sep 21, 2010)

Hi HKJ,

Can you comment on the build quality? 

Thanks


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## HKJ (Sep 21, 2010)

SCpooh said:


> Hi HKJ,
> 
> Can you comment on the build quality?
> 
> Thanks



OLight usual has a good build quality.The M31 looks nicely done, only place where you have some sharp corners are the teeth on the tailcap. The threads has fine tolerances. 
What I could have wished for was square threads with a coarser pitch and stainless steel bezel and tailcap.


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## dhouseng (Sep 22, 2010)

Is the 2222mA the tailcap current? I got 2060mA yesterday and only 1900mA now regardless of any battery set I use. Anyway to make it draw current as much as yours?

Edit: Ok, I think the tail current goes up when voltage drops.


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## HKJ (Sep 23, 2010)

dhouseng said:


> Is the 2222mA the tailcap current? I got 2060mA yesterday and only 1900mA now regardless of any battery set I use. Anyway to make it draw current as much as yours?
> 
> Edit: Ok, I think the tail current goes up when voltage drops.



Your last remark explains it perfectly. In my review I have a voltage scan, where you can see the current draw at different voltages.


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## Oztorchfreak (Oct 4, 2010)

HKJ said:


> OLight usual has a good build quality.The M31 looks nicely done, only place where you have some sharp corners are the teeth on the tailcap. The threads has fine tolerances.
> What I could have wished for was square threads with a coarser pitch and stainless steel bezel and tailcap.


 

I can add to the wish for better screw threading as I have only just received a replacement Olight M30 due to the screw threads wearing out after only 11 months.


The threads on the left is my M30 worn out torch body. The ones on the right are of the M30 unused battery extender. 








Luckily it was replaced under the Olight 24 month warranty.

I posted about this on CPF as below.

https://www.candlepowerforums.com/threads/290911

I still get people saying that I abused the torch, but even the dealer stated that he could not explain the bad threads.

This is something that could happen to the Olight M31 as well.


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## R-lights (Oct 4, 2010)

Hi All - Great review! I'm new to the site, and find these reviews very - - - extremely helpful. I'm moving from an Olight M30 to and M-31. If there are any owners here that can help with a few questions, that would be great! 
First - what's the real deal with the heat? I'm thinking my application would be in the 10-20minute on constant range - would that be an issue?
Also if anyone has either the M31 & SR50? Wondering if other than the look and interface there are any real differences between them? 

Cheers & many thanks - R-lights


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## HKJ (Oct 5, 2010)

R-lights said:


> what's the real deal with the heat? I'm thinking my application would be in the 10-20minute on constant range - would that be an issue?



If you want to stand it on a table for 10 to 20 minutes it will get rather hot, but probably still within the safe limit.
If you are holding it in your hand it will have better cooling and not get as hot, i.e. no problem.
If you place it under a pillow for 20 minutes it will probably cook itself.

The problem with cooling is that it is very depends on external factors, a hand or airflow will increase the cooling a great deal.


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## dhouseng (Oct 7, 2010)

I did a little regulation test today without the extension tube.

Will do another test when my 2x18500 arrives.


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## mike6187 (Oct 14, 2010)

Nice write up here! thanks for sharing it to everyone


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## Halfpint (Oct 26, 2010)

HKJ,

Thanks for the great review! 

Definitely solidified my decision to buy a SR91 as my next `step up' from my M30 `Smooth Tailcap'. That is *not* to say that I won't eventually add an M31 to my Olight `collection. I'll just sit back and get one when I finally get `a round tuit'. {GRIN!}

Just an `Olde Fart's' 2¢ worth? {VB GRIN!}


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## dhouseng (Oct 27, 2010)

The M31 is fully regulated with 2x18500.

Runtime is 33 minutes and a sudden shut down with no dimming at all according to my lux meter. Measured the batteries and they both read 3.64 volt, not quite sure what's triggering the shut down.


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## CaptPat (Oct 27, 2010)

Greetings, I'm new to the site, and find these reviews very helpful. Thanks


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## MichaelW (Oct 28, 2010)

dhouseng said:


> The M31 is fully regulated with 2x18500.
> 
> Runtime is 33 minutes and a sudden shut down with no dimming at all according to my lux meter. Measured the batteries and they both read 3.64 volt, not quite sure what's triggering the shut down.



How hot were the cells?


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## dhouseng (Oct 29, 2010)

MichaelW said:


> How hot were the cells?



Barely even warm.


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## phantom23 (Oct 29, 2010)

dhouseng said:


> Measured the batteries and they both read 3.64 volt, not quite sure what's triggering the shut down.


Very high current (about 2C), are your cells protected? + remember that voltage drops at high current.


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## zehnmm (Oct 30, 2010)

Hello folks. After reading countless CPF posts, including this thread about 3 times, I pulled the trigger and got an M31. My finalists in my search included the ThruNite Catapult and the Jetbeam RRT-3. Eliminated the RRT-3 due to cost. Was a close call between the M31 and the Catapult. Chose the M31 because, even though it cost more, I got 2 more modes (low and strobe) and a few other reasons. To be honest, I could have chosen the Catapult and probably would have been very pleased.

Before I proceed further, I say thanks to HKJ for his top notch work. Also, no thanks to HKJ and all the rest of of you for your enabling of my illness here! :naughty: Heh, heh.

Anyway, all kidding aside, my first impressions are that this appears to be a quality well-made light. Cannot wait for darkness to test it out. Sure does seem bright on high in a dark room. I had no trouble cycling through the modes. If I hold it kind of up front, I found I could do it one-handed. While I do not like the strobe just past high, wherein I have to cycle past strobe to get from high to low, I can live with it.

FYI, my AW flat-top 2200mah 18650 cells did not power it up. My new AW 2600mah 18650s with the 3 small triangulated dots on the negative side work, as do the older AW 2200mah button tops. Three CR123s in the included battery holder work. But, when I tried 4x CR123s, with the battery holder and the extender, it would not work. 4x CR123s without the battery holder did work. Having said this, my plan is to run it with two 18650s, with two more as back-up. As another backup, will use 3x CR123s in the battery tube on the light without the extender. That should give me quite a bit of usability and runtime.

I might say that the more I learn about the Luminus SST-50, the more I am impressed with it. Probably will not be my last one. My planned use is to run my light mostly on the medium level, with the advertised 320 lumens otf, with up to 3.5 hours of run time. Then with one quick twist of the head, I get the high mode when I need it. We live out in the county in the foothills of the mountains in south central New Mexico. This light will be used pretty much nightly/early morning on dog walks; moreover, since we are now in elk hunting season around here, we get our share of poachers. I need a good thrower light to let 'em know that I am ready to call the sheriff and game wardens. So far, have been using an MN16 in a KT4 head on a Leef 2x18650 body. In 3 separate instances after shining the light some 250 yards away from suspected poachers (behind cover, but with my Kimber Stainless Target II in 10mm at the ready) they get the heck out of there pronto. But, the MN16 runtime is less than an hour, and the throw, while pretty decent, is not as far as I would like. I need about 200 yards or more of decent throw with reasonable spill.

Additionally, will use the light for a bump-in-the-night light to check things out. Out here, we have mountain lions, bears, wolves, coyotes, elk, deer, skunks, and other creatures such as neighbor's dogs on the loose. Sometimes we have had burglars prowling around too. Being able to light up things around our house is a big deal to me. Until now, the go-to lights for this have also included my ROP Low Mag 2d and my 4D Mag with an Osram 65W IRC bulb at over 3,200 otf lumens running off of 5x AW IMR 26500s. Runtime on that latter beast is about 20 minutes, where I cannot run it more than about 3 minutes straight due to heat issues. 

While I dearly love my incan hotwires, I guess you can say that I have now partaken of the LED kool-aid.

I will post some more after I get more experience with it.

Blessings,

Steve


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## Swedpat (Oct 30, 2010)

HKJ said:


> The light has a very fine regulation on 18650 batteries and also a good runtime, *but 3xCR123 batteries do not really work in the light, at least not on high.*



A bit late to comment, but thanks for another great review! :thumbsup:

The question I have is if M31 works well at high with 4xCR123? 
The throw seems to be impressing, it totally outperforms Fenix TK30/40 in this respect!


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## HKJ (Oct 31, 2010)

Swedpat said:


> The question I have is if M31 works well at high with 4xCR123?



I have not tested with 4xCR123, but I will expect it to do considerable better. With four batteries the voltage will be higher i.e. less current draw, and each battery can go down to a lower voltage, before the light has a problem.
The only downside is a higher risk for reverse polarisation of the batteries , i.e. it is very important to use batteries with equal capacity (All batteries same type and only load with new batteries).



Swedpat said:


> The throw seems to be impressing, it totally outperforms Fenix TK30/40 in this respect!



The TK30/TK40 was never designed as throwers (they uses a shallow OP reflector).


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## Swedpat (Oct 31, 2010)

HKJ said:


> I have not tested with 4xCR123, but I will expect it to do considerable better. With four batteries the voltage will be higher i.e. less current draw, and each battery can go down to a lower voltage, before the light has a problem.
> The only downside is a higher risk for reverse polarisation of the batteries , i.e. it is very important to use batteries with equal capacity (All batteries same type and only load with new batteries).
> *Do you here mean a higher risk for placing some battery wrong way or that they will change polarisation when running low? * *(Excuse a stupid question)...**:thinking:*
> 
> ...


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## HKJ (Oct 31, 2010)

*



Do you here mean a higher risk for placing some battery wrong way or that they will change polarisation when running low?

Click to expand...

**

The problem is when running low, M31 has a very high current drain and with four batteries in series you have voltage enough to get a rather high reverse polarisation voltage if there is one weak battery.



*


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## Swedpat (Oct 31, 2010)

Thanks HKJ, I understand now!


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## zehnmm (Oct 31, 2010)

Hi folks. Update of my previous post with some thoughts not necessarily in any order.

Got to use the light a bit and compare with my other lights. This light is indeed a good thrower; bright hotspot, sensible amount of spill. No Cree-type LED rings. I am satisfied about its ability to allow for me to see what is going on 200 or more yards. In my old, rather untrained eyes, the medium and high modes seem similar to my ROP low and high. But, if the advertising is true to form, I would get over 3 hours of run-time on the medium mode, advertised at 320 otf lumens. 

The medium mode is really what I am planning to use the most. One question that I had was how would that mode do at 200 yards. I found out that I could see well enough on that mode to make out things. But, if I need the high mode to get a better look, then I have it. By the way, while it is possible that the high mode might really be 800 otf lumens in the first second or so, to me it seems more like 700. Not anything empirical here, just my opinion.

Also, the low mode seems to be very similar to my E2E incan rated at around 60 lumens. 

Of course, the color temp on the M31 appears to be at least a 5700 and maybe even a 6500. Obviously the warmer temps in the incans are very noticeable outdoors versus the M31. 

I am ok with the M31 color temp. However, the next SST-50 that I get will have something warmer, perhaps a 4500. Probably get one from Nailbender.

All in all, I am glad I got the light. 

Regards,

Steve


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