Thrunite Neutron Series (XM-L) 1C, 2C, 1A, 2A Review: RUNTIMES, BEAMSHOTS and more!

[MichaelW]

Is the Neutron 2AA better in runtimes compared to the Fenix LD20 (I saw the graph on max output ... and WOW , but what about on Med and Low ?!). I had decided that I would go for the Fenix but now that this light came ... I'm not so sure - what do you think is a better overall light ? Also something very important is that I will use it a lot for camping, so is there a diffuser that will fit the Neutron so perfectly as it is the case with the LD20 ?!?

Thrunite has said they will offer neutral xm-l ASAP, so that seems perfect for camping.
I don't know if the Neutron needs a diffuser, because it is almost pre-diffused (using the 4mm^2 xm-l instead of the 2mm^2 xp-g that the Fenix LD20 R5 uses)
and the Neutron has an ultra low 'firefly' mode that the Fenix does not (I wonder how long until they add a fifth output mode?)

and Neutron might fix the mushy switch/cover

 

[selfbuilt]

Is the Neutron 2AA better in runtimes compared to the Fenix LD20 (I saw the graph on max output ... and WOW , but what about on Med and Low ?!). I had decided that I would go for the Fenix but now that this light came ... I'm not so sure - what do you think is a better overall light ? Also something very important is that I will use it a lot for camping, so is there a diffuser that will fit the Neutron so perfectly as it is the case with the LD20 ?!?

Sorry, I've done all the runtimes I'm going to for the Neutrons, moving on to other lights that need testing. You should be able to guestimate the Med mode runtime by comparing capacities of some of the other lights where I've tested both med and hi.

As for a diffuser, not sure what would fit off-hand (I'm out of town and don't have the lights with me to test). If you compare the head diameters to other lights, you should be able to figure out a few options. But see how you like it without the diffuser - the beam is pretty floody on its own.

 

[Gondwana]

... so is there a diffuser that will fit the Neutron so perfectly as it is the case with the LD20 ?!?

I have just bought 1A Neutron. I have also bought Fenix filter set (two wands, red filter and flipping diffuser). The flipping diffuser fits perfectly on my 1A, wands needed a little modding: I just carved out the last 4-5mm of the ribs inside them. Doesn't fit so stable as on LD10/LD20, but for my opinion it is usable.

I wanted to buy LD10 R4 but this shop just ran out of them, I could have chosen LD20 R4 or LD10 R5. I have tried mixing heads: the R5 head was noticably worse than the R4 head on both tubes, and then they showed me they have 1A, not even listed in their pricelist. Seeing the difference, I have momentarily abandoned Fenixes.

 

[raphaello]

http://fonarik.com/test/indexen.php?model=6&scene=3&mode=0

http://fonarik.com/test/indexen.php?model=153&scene=3&mode=0

It is the same with the corridor picture. Am I the only one who thinks that the Neutron 2AA should have been A LOT brighter than the LD20 :thinking:
What's the deal .... ?!?!

 

[LeifUK]

http://fonarik.com/test/indexen.php?model=6&scene=3&mode=0

http://fonarik.com/test/indexen.php?model=153&scene=3&mode=0

It is the same with the corridor picture. Am I the only one who thinks that the Neutron 2AA should have been A LOT brighter than the LD20 :thinking:
What's the deal .... ?!?!

It does look odd. The Neutrons have a slightly narrower spill, but a wider brighter hot spot, but they don't look bright enough in those fonarik images.

 

[MichaelW]

It does look odd. The Neutrons have a slightly narrower spill, but a wider brighter hot spot, but they don't look bright enough in those fonarik images.

I think all the extra light is in the spill, see the Vault picture-that one is telling.
I hope Cree will make an LED that splits the difference between the xm-l & xp-g.

 

[raphaello]

Yes, the Vault picture really shows the difference ! But ... there is something wrong with the other two (the corridor and the wall). Even the spill on the Neutron is A LOT dimmer than the LD20 on those two

 

[selfbuilt]

It is the same with the corridor picture. Am I the only one who thinks that the Neutron 2AA should have been A LOT brighter than the LD20 :thinking:
What's the deal .... ?!?!

There's clearly a mismatch with the pictures - the 2A is a lot brighter in the spill than the LD20-R4.

FYI, I notice only 3 modes are listed for the 2A pics - when in fact there are 4 modes available beyond firefly (i.e. they are supposedly showing Lo, Hi, and Turbo, but not Med?). Just guessing here, but I suspect the "255 lumens" and "103" lumen pics are in fact the Hi (120 lumen spec) and Med (50 lumen spec) modes, and Turbo (255 lumen spec) has not actually been taken. That would fit a lot better with my subjective experience (and my white-wall beamshots).

 

[Jared]

Thrunite has said they will offer neutral xm-l ASAP, so that seems perfect for camping.
I don't know if the Neutron needs a diffuser, because it is almost pre-diffused (using the 4mm^2 xm-l instead of the 2mm^2 xp-g that the Fenix LD20 R5 uses)
and the Neutron has an ultra low 'firefly' mode that the Fenix does not (I wonder how long until they add a fifth output mode?)

and Neutron might fix the mushy switch/cover

I keep asking the same question. I am about to get a Neutron 1A but I'm still questionable. I really wish Fenix would start adding a firefly mode. I don't care if its PWM or not. The added functionality of just the one mode is huge. Also use of an X-ML (cool AND neutral white) in a EDC would be REALLY nice to see from Fenix (just imagine what their efficiency could be like at lower drive currents). I just don't think they are willing to step away from their traditional four mode with +2lm lows and only using a die that is small enough to still give their "standard" beam pattern.

To cut this short my point is it says something that I'm about to sacrifice a premium build and trustworthy name just for an added mode and larger output range. I'll wait a while though. See if anybody is listening.

 

[flashflood]

I keep asking the same question. I am about to get a Neutron 1A but I'm still questionable. I really wish Fenix would start adding a firefly mode. I don't care if its PWM or not. The added functionality of just the one mode is huge. Also use of an X-ML (cool AND neutral white) in a EDC would be REALLY nice to see from Fenix (just imagine what their efficiency could be like at lower drive currents). I just don't think they are willing to step away from their traditional four mode with +2lm lows and only using a die that is small enough to still give their "standard" beam pattern.

To cut this short my point is it says something that I'm about to sacrifice a premium build and trustworthy name just for an added mode and larger output range. I'll wait a while though. See if anybody is listening.

If Fenix makes such a light, and history is any guide, it will not support 14500. If you get the 1A or 1C and throw an AW IMR 14500 or 16340 in there (which Thrunite explicitly does support), I predict it will instantly become one of your favorite lights. 300+ lumens OTF, from something about the size of a roll of pennies. Love it!

I have and like Fenix and 4sevens lights, but the lack of explicit Li-Ion support in (most of) their AA, AAA, and CR123 single-cell lights has become a deal-breaker for me. Thus iTP A3 is on my keychain, and Thrunite Neutron 1A and 1C are my small EDCs.

 

[Xak]

If Fenix makes such a light, and history is any guide, it will not support 14500. If you get the 1A or 1C and throw an AW IMR 14500 or 16340 in there (which Thrunite explicitly does support), I predict it will instantly become one of your favorite lights. 300+ lumens OTF, from something about the size of a roll of pennies. Love it!

I have and like Fenix and 4sevens lights, but the lack of explicit Li-Ion support in (most of) their AA, AAA, and CR123 single-cell lights has become a deal-breaker for me. Thus iTP A3 is on my keychain, and Thrunite Neutron 1A and 1C are my small EDCs.

4Sevens lights support 14500 in their one cell, Quark regular and tactical AA lights... explicitly. I'm waiting for him to jump on the XM-L neutral and warm bandwagon. I just know that as soon as I buy a new XP-G QAA (I lost my old R2 QAA) he will come out with the XM-L. I have other lights, so no rush.

 

[B0wz3r]

The only benefit is the neat strobe effect in the rain. This novelty wears off after about 10 seconds and then becomes a total annoyance.

I have the 2C. The PWM sucks big time. If I'd known I wouldn't have bought it.

I assumed 100Hz wouldn't be visible as flicker and thought that it must be lower (like 50Hz) but I was wrong. It certainly looks less to me.

I'm going to make a guess as to why the lowest PWM mode is the most annoying and say that the total light output is low enough that the eyes rods are being used and the PWM rate is too low to maintain persistence of vision and reach the flicker fusion threshold. At the higher levels the light output becomes high enough to bring the cones of the eye into use which have a higher persistence of vision (1/20 second) and therefore lower flicker fusion threshold.

Some quick research into this reveals that some of the more sensitive parts of the eye can detect flicker up to 250Hz !!!!

So it's time for manufacturers to reassess their PWM strategies and for buyers to force this by not buying products that don't meet the standards that we set (come to think of it - we should get together as a group and set some standards that we expect as a minimum).

I'm just going to ramble a bit here, so bear with me, and hopefully some of what I have to say will make sense and/or be helpful with understanding this whole PWM issue...

I'm not aware that there's a temporal difference in persistence between rods and cones, but I'd have to look it up to be sure. I'm not an expert on rhodopsin characteristics, but one of my professors from grad school when I was getting my PhD in perceptual psychology at UC Santa Cruz, Gene Switkes, is... I'll have to look up some of his papers and see if he's done anything on differences in the characteristics of the pigments in rods vs cones. Just of the top of my head, I'd say that sensitivity to PWM because of differences between rods and cones is more about the differential sensitivity they have; a cone requires 5 - 6 photons to generate an action potential, whereas a rod only requires 1 - 2, so your hypothesis is certainly possible, but I'd think that overall even with the PWM the total light output would be enough to activate the cones, and at that point the intensity of the light is so high the rods get overwhelmed and essentially shut down and don't work (as in photopic vision).

With respect to flicker sensitivity, the critical flicker fusion (CFF) rate is a function of the intensity of the light. The greater the intensity of the light, the higher the rate needs to be for the light to be perceived as continuous rather than strobing/flickering, so in general, a lower PWM rate is less noticeable at low levels than high levels. I'm not an electrical engineer, so I don't know if it's possible to design a circuit that would vary the PWM rate based on the output level, but I would imagine it's cheaper and easier to build a driver that uses the same rate at all output levels. Still, the reason as to why the 2C uses such a low rate is baffling to me, and aside from the fact I don't do 123 format lights, I'd never get one because I am fairly sensitive to PWM.

Anyway, please pardon the early Sunday morning ramblings of a tired old psychophysics professor... haven't had my caffeine yet...

PS: I have to say, I really like the beam profiles of these lights... I love the large hotspot in the beam... the idea of having most of the beam be hotspot and the minority of it as spill is a very appealing profile to me for my EDC preferences. Although I find the poor regulation a put-off and the fact they're only available in cool tints right now too means I'll be waiting until they come out with neutral versions (IF they come out with neutral versions that is...)

 

[MichaelW]

I think there is a difference in the temporal resolution between rods/cones, or at least foveal/non-foveal vision.
Example: watching television with ceiling fan on. [lowest setting] The angular velocity seems greater when you are not looking at the fan, but when you turn to look at the fan, it seems to slow down.

 

[tre]

Excellent reveiw. I have one question. Your table at the end of the review shows lumen outputs and you said they are not ANSI standard measurements. The tables throughout the review show the same lumen numbers but say they are ANSI measurements. I am looking at the Turbo output for the 1A to be specific. It shows as 240 lumens in all the tables while Thrunite estimates 145 lumens. I'm wondering if the light is much brighter than their specs or if they are using ANSI and you measured turn on lumens? thanks selfbuilt.

 

[selfbuilt]

Excellent reveiw. I have one question. Your table at the end of the review shows lumen outputs and you said they are not ANSI standard measurements. The tables throughout the review show the same lumen numbers but say they are ANSI measurements. I am looking at the Turbo output for the 1A to be specific. It shows as 240 lumens in all the tables while Thrunite estimates 145 lumens. I'm wondering if the light is much brighter than their specs or if they are using ANSI and you measured turn on lumens? thanks selfbuilt.

All I mean in that last table is that those are initial activations, whereas the earlier tables are at 3 mins into the run (i.e. ANSI FL-1 standard). I do get ANSI estimated lumens at 240 for the 1A on 1xNiMH. This is higher than their spec, so I suspect they are somewhat low-balling the value.

 

[tre]

My confusion is that your ANSI (3 minute measurements) in turbo mode are the same as the initial turn on measurements in turbo mode for both the Neutron 2C and Neutron 1A. Is this really the case? I am confused because I don't recall any light making the same amount of lumens at turn on as it does after 3 minutes (especially in turbo mode).

 

[selfbuilt]

My confusion is that your ANSI (3 minute measurements) in turbo mode are the same as the initial turn on measurements in turbo mode for both the Neutron 2C and Neutron 1A. Is this really the case? I am confused because I don't recall any light making the same amount of lumens at turn on as it does after 3 minutes (especially in turbo mode).

If you look at the runtime graphs, you will see the 2C is indeed completely flat output on Turbo on RCR or CR123A is (hence why time 0 and 3 mins are the same lumen estimates). 14670 has a very slight dip, hence the the small change in estimate lumens between the two tables.

Same for the 1A - the 14500 is indeed different (reported as such in the two tables). But Eneloop is pretty flat over the first 5 mins. There is a slight dip, but it is caught within the rounding estimate for my lumens conversion (i.e. I get 242 at time 0, 236 at time 3 mins, so both get reported as 240 estimated lumens). Given my setup, I don't feel it is accurate to report lumens to any greater level of precision.

 

[tre]

If you look at the runtime graphs, you will see the 2C is indeed completely flat output on Turbo on RCR or CR123A is (hence why time 0 and 3 mins are the same lumen estimates). 14670 has a very slight dip, hence the the small change in estimate lumens between the two tables.

Same for the 1A - the 14500 is indeed different (reported as such in the two tables). But Eneloop is pretty flat over the first 5 mins. There is a slight dip, but it is caught within the rounding estimate for my lumens conversion (i.e. I get 242 at time 0, 236 at time 3 mins, so both get reported as 240 estimated lumens). Given my setup, I don't feel it is accurate to report lumens to any greater level of precision.

I see that now. Thanks for pointing that out. That is pretty amazing. Do you put it down to superior heat sinking or the efficiency (and lower heat) of the XML driven at lower levels?

 

[Lighteous]

I have a 1C and I am generally very pleased with it. It is easily the brightest single CR123 cell that I have. My only complaint with this light has been the "squishy" clicky and how it prevents tailstanding. I noticed that when I replace the cell and screw the tailcap down the boot seems to slighltly inflate because of the internal air pressure. This exacerbates the inabiliy to tailstand issue. However, I noticed that if I loosen and re-tighten the bezel the pressue is released, the boot flattens out and then the light can tailstand with ease. It sounds crazy, I know. But before posting this I tested this procedure three times with the same result. I will be interested to learn if anyone else has this result.

 

[selfbuilt]

Do you put it down to superior heat sinking or the efficiency (and lower heat) of the XML driven at lower levels?

Probably the latter, but hard to know.

I noticed that when I replace the cell and screw the tailcap down the boot seems to slighltly inflate because of the internal air pressure. This exacerbates the inabiliy to tailstand issue. However, I noticed that if I loosen and re-tighten the bezel the pressue is released, the boot flattens out and then the light can tailstand with ease. It sounds crazy, I know. But before posting this I tested this procedure three times with the same result. I will be interested to learn if anyone else has this result.

The phenomenon of outgassing is well known with multiple NiMH cells in lights with similar tailcap (i.e. Fenix LD20, etc.). But that only occurs after running the light for awhile, when one of the cells is not in very good shape anymore. Can't think of anything similar for a 1xCR123A light - in fact, I would be rather worried if it did happen (i.e. release the pressure and dispose of the cell immediately, if the tailcap bulges while running a 1xCR123A light). But if I understand you correctly, it's only when you first tighten the tailcap? If so, I'm not clear why it would be happening. :thinking: