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Thread: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

  1. #1

    Rolleye11 Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Reviewer's note: This is going to be a shortened "mini-review" of the Fenix LD12. It will still contain all the detailed analysis, measurement and runtimes – but will be less detailed on the background information and pics. For those looking for info on the overall light build, please check out my video overview below.

    The LD12 is the current premium 1xAA model available from Fenix – and it has come a long way from Fenix's inaugural single-stage flashlight, the L1P.




    Through the years, I have owned most of the Fenix line in the 1xAA battery format - through the L1T (both Luxeon III and Rebel R80 versions), L1S (Luxeon I), L1D (Cree XR-E P4, Q2, and Q5 versions, as well as Rebel R100 version), to eventually the LD10 (Cree XP-G R4). I've even had the E11 for good measure (Cree XP-E).

    But what I've been missing in my nearly complete compilation has been the more recent LD12 (originally Cree XP-G R5, but now available with XP-G2 R5). I've decided to rectify that situation, and have picked up a recent XP-G2 R5 version ("125 lumens") from a local dealer. Let's see how it compares to other modern 1xAA lights.

    Manufacturer Reported Specifications:
    (note: as always, these are simply what the manufacturer provides – scroll down to see my actual testing results).




    You can find the current XP-G2 R5 version of the LD12 for ~$52 at authorized Fenix dealers.



    Fenix packaging has been fairly standard for a few years now – although I've found they've increased the specification details on the box over time (see above). Inside, you get the standard extras, similar to my LD10 review – basic wrist strap/lanyard, extra o-rings, extra tail boot cover, decent quality holster with Velcro closing flap, detailed manual, and product inserts. A titanium clip in included on the light.

    As an aside, Fenix is one of the better makers for providing reliable and consistent ANSI FL-1 standard measures on their products.



    From left to right: Duracell AA NiMH; Fenix LD12, LD10; Sunwayman V11R + AA extender, Zebralight SC52; Olgith S15; Nitecore EA1, MT1A.

    All dimensions are given with no batteries installed:

    Fenix LD12: Weight: 52.3g, Length: 99.9mm, Width (bezel): 21.6mm
    Fenix LD10: Weight: 53.4g, Length: 104.2mm, Width (bezel): 21.7mm
    Lumintop ED15: Weight: 59.7g, Length: 100.1mm, Width (bezel): 21.2mm
    Nitecore MT1A: Weight: 54.6g, Length: 104.6mm, Width (bezel): 22.7mm
    Nitecore EZAA: Weight 20.9g, Length: 85.0mm, Width (bezel) 16.6mm
    Rofis ER12: Wright: 35.5g, Length: 96.2mm, Width (bezel): 18.6mm
    Xeno E03:: Weight: 48.1g, Length 96.7mm, Width (bezel): 21.5mm
    Zebralight SC52: Weight 39.5g, Length 79.0mm, Width (bezel): 22.6mm, Width (max) 25.4mm

    The LD12 is a little larger than the LD10, due to the extra control switch in the head. Overall dimensions are still quite reasonable for the tail clicky-switch group of 1xAA lights.



    For detailed comments on the overall build, please see my video overview below.

    One feature I will highlight is the mode-changing switch in the head has pretty good feel for an electronic switch. It is relatively easy to locate by feel, and has a definite click, with typical traverse.

    There is also an unusual metal contact clip in the tailcap now. This appears to have replaced the more common switch retaining ring mechanism (i.e., it holds the switch in place). Not sure why the change, but it will likely prevent the common issue of the retaining ring unscrewing loose over time.

    Aside from these two obvious changes (and the new XP-G2 emitter), the overall build is similar to the LD10 (just longer now due to the secondary switch).

    User Interface

    Turn the light on/off by the forward tailcap switch. Lightly press and hold for momentary, click (press and release) for constant on. Click again to turn off.

    To change modes, click the electronic switch in the head while on. Mode sequence is Lo > Med > Hi > Turbo, in repeating sequence. The light has mode memory, and returns the last level set after turning the tail switch off/on.

    Press and hold the electronic switch to access an oscillating Strobe mode. Press and hold again to switch to SOS. A single click exits you from the blinking modes back into constant output.

    Video:

    For information on the light, including the build and user interface, please see my video overview:



    Video was recorded in 720p, but YouTube typically defaults to 360p. Once the video is running, you can click on the configuration settings icon and select the higher 480p to 720p options. You can also run full-screen.

    As with all my videos, I recommend you have annotations turned on. I commonly update the commentary with additional information or clarifications before publicly releasing the video.

    Oscilloscope Traces

    There have been concerns raised here that Fenix is using Pulse Width Modulation (PWM) on the LD12 (see this thread for example). The only way to clarify this question is with proper oscilloscope traces.

    First off, I should explain that my oscilloscope setup uses an optical transducer – so my traces always reflect actual perturbations in visual output at the emitter. Many oscilloscope reports are based on electrical voltage/current differences going into the emitter (which should correlate with output, but may not look exactly the same as my actual output ones).

    Below is a comparison of each of the four output modes on my sample – all shown on the same time and amplitude scale (i.e., to allow direct relative comparisons):

    LD12 Lo mode:


    LD12 Med mode:


    LD12 Hi mode:


    LD12 Turbo mode:


    I will explain what is going on in more detail below, but the take-home message is that the LD12 is most definitely NOT using PWM for its low modes - but it does have a reoccurring signal present in the Med-Turbo modes in the frequency range that can be perceptible as "flicker" for sensitive individuals.

    Scroll down to post #2 for a detailed discussion of what PWM is (and isn't), and what to look for in oscilloscope traces. But to summarize, PWM is never present on Max, has a constant frequency and amplitude across lower levels, has a square wave pattern, and is only variable for pulse width. In contrast, my LD12's reoccuring signal is the opposite of the PWM - it is a signal of variable frequency and amplitude, has a sine wave pattern with nearly perfect periodicity (i.e., shows constant width), and is present on the Max level but not Lo. Here's a close-up of the LD22 Hi mode:



    All of the above clearly rules out PWM. Again, see post #2 for more info.

    But even though there is no PWM, the visual oscillations on the LD12 are a potential problem, as their frequencies are in the known perceptual flicker range (i.e. 700-1100 Hz). That said, you may not be able to see it unaided by eye on the LD12, due to the differing waveform and amplitude of this signal.

    So, the main question is can you see this signal as "flicker" on the LD12? I can only speak for myself (and this one sample), but I can only visually detect the presence of flicker on the Med mode of my LD12 (i.e., the level with the greatest amplitude and lowest frequency). It is very subtle, and much less noticeable that PWM flicker would be at this frequency and output level. I can see no apparent signs of flicker on Hi, Turbo or Lo during actual use (and I am personally susceptible to noticing flicker). And even when shinning on a fan, I can only see stroboscopic evidence on Hi and Med. But of course, your sample could vary from mine.

    A secondary question is do these oscillating signals affect the runtime performance/efficiency of the light? For the answer to that, you'll have to scroll down to my runtimes section.

    I will discuss the likely source of this oscillating signal in the preliminary discussion section of my review. Note that I expect the presentation of this signal may be quite variable from one LD12 sample to the next.

    Before I move on, I've read that some people have also reported seeing a change in flicker when switching modes on the LD12 (i.e., not present on activation, but present after cycling modes). I do not observe that on my sample, but I do see something interesting when switching from Turbo to Lo – there is a strong flicker effect during the ramping phase from max to min output. Forgive the rather messy trace below, but it should give you the idea of what happens as you press the switch (which occurred ~75 msecs into the run below):



    And here is a blow up that I managed to catch just as the switch was pressed (at ~10 msecs into the run below):



    The first pulse is the standard Turbo mode oscillation, followed by the start of the ramp down to low. As you can see, the amplitude of the oscillation increases immediately during the ramp – basically, as the light ramps down to Lo from Turbo, it passes through the Hi and Med states (with their large amplitude and lower frequency oscillations). However, once the light reaches the Lo mode, output remains perfectly stable with no signal on my sample.

    So while I never saw any flicker whatsoever on the Lo mode on my sample, I can visually see a clear flicker during the ramping down phase from Turbo to Lo. But again, your sample could vary from mine.

    Strobe/SOS

    The LD12 has two "hidden" blinky modes:

    Strobe:


    The LD12 switches between two strobe frequencies – 7.2 Hz and 18.2 Hz - every 2 secs. Here's a blow up of the switching point:



    SOS:


    The LD12 has a fairly typical speed SOS mode.

    Beamshots

    Since this is a mini-review, I've decided to forgo beamshots. But the LD12's beam doesn't look appreciably different from other XP-G/XP-G2 lights in this size. There were no significant beam rings on my sample, although I can detect the common small dark centre in the hotspot (common to many XP-G/XP-G2 lights with smooth reflectors).

    Testing Method:

    All my output numbers are relative for my home-made light box setup, as described on my flashlightreviews.ca website. 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, except for any extended run Lo/Min modes (i.e. >12 hours) which are done without cooling.

    I have devised a method for converting my lightbox relative output values (ROV) to estimated Lumens. See my How to convert Selfbuilt's Lightbox values to Lumens thread for more info.

    Throw/Output Summary Chart:

    My summary tables are reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. Please see http://www.flashlightreviews.ca/FL1.htm for a discussion, and a description of all the terms used in these tables. Effective July 2012, I have updated all my Peak Intensity/Beam Distance measures with a NIST-certified Extech EA31 lightmeter (orange highlights).



    Interestingly enough, max initial output of my LD12 (XP-G2 R5) is actually a bit lower than my LD10 (XP-G R4), despite being in essence three output bin steps higher now.



    Fenix has very believable output and throw specs for their lights, which as you can see match fairly closely to my output estimates and throw measures.

    But to better understand how the LD12 performs, we need to look at the actual runtimes.

    Output/Runtime Comparison:

    There has been some concern here that the visible high frequency flicker phenomenon on the LD12 may result in lower-than-expected runtimes. But as I explained above, the oscillating signals shown on my sample are not PWM. I would therefore not expect them to affect runtimes (which are usually excellent on Fenix lights)

    Given that, I was a bit concerned when performing my initial runtime tests – but I was able to quickly track down the source to a separate problem, and resolve it.



    What you are looking at above at three runtime attempts on Turbo on Eneloop NiMH (using the same battery). Clearly, something doesn't look too good on the first attempt. It was actually even worse than the above runtime appears, since I am only using a 30 sec sampling frequency above (i.e., one reading every 30 secs). Here's my initial two Med mode runtimes on a 1 sec sampling frequency and time scale:



    Basically, something was causing reduced output on my initial runtimes (with periodic jumps in output, as you can see on the second timescale). This produced lower overall output and runtimes than expected.

    I surmised that this had nothing to do with the "flicker" effect observed on my oscilloscope traces (as that happens on a millisecond time scale, and is quite periodic). Instead, the problem on these initial runtimes looked to me like an example of some sort of intermittent contact issue. I therefore carefully cleaned all contact surfaces with high-proof rubbing alcohol and Deoxit, and re-ran the runtimes (i.e., the subsequent attempts you see above). This completely resolved the problem for the rest of testing period.

    How does the clean LD12 compare to the competition?





    The overall efficiency and regulation pattern of the LD12 (after a thorough clean) is consistent with a good current-controlled light.

    There is certainly nothing here to cause me any concern with the LD12's performance. You can see an extended runtime compared to my LD10 (XP-G R4), for example.

    UPDATE: Here are some alkaline runtimes:




    Potential Issues

    My LD12 sample shows signs of a reoccurring signal in the potentially visible "flicker" range. This is most definitely NOT pulse width modulation (PWM), but it could still be potentially visible on some modes, on some samples, to some people. I am personally sensitive to flicker, but was only able to notice it visually on the Med mode of my sample. Note that the subjective flicker in this case was not as visually noticeable as true PWM of that same frequency would be (for a comparable output level). In any case, I suspect the intensity of this signal issue will be variable across LD12 samples. See my detailed comments in the Oscilloscope and Preliminary Discussion sections of this review.

    My sample had contact issues that led to some by fluctuations in output and runtime. A single thorough cleaning resolved these issues for the duration of the testing period.

    Max output is not any higher than my earlier LD10 XP-G R4 (but runtime has of course increased, thanks to the higher output bin on my LD12 XP-G2 R5).

    1x14500 Li-ion 3.7V are not supported (i.e., standard AA cells only).

    Tailstanding was completely unstable on my sample, due to the bulging switch cover.

    Preliminary Observations

    I've long been a fan of 1xAA lights in general – and Fenix's offerings in particular. I have owned many of the various 1xAA model they have made over the years, except for the LD12 – until now.

    My LD12 sample contains the new XP-G2 emitter (R5 output bin) – although in this case that doesn't translate into much of an output difference. Fenix seems to have focused on a balanced range of output levels, and has not chased higher max outputs. Indeed, steady-state output of my LD12 XP-G2 R5 is basically the same as my LD10 XP-G R4 (even though XP-G2 R5 is basically three output bins up from the XP-G R4).

    The mode-changing electronic switch is the most distinctive feature of the LD12 (and a real departure from the all the earlier AA-series lights). But Fenix got the interface right in my view, with a Lo > Turbo sequence and "blinky" modes hidden away under press-holds of the switch. Personally, I'm still fine with head twisting for mode changes, but this is a good implementation of an electronic side switch.

    One of my interests in picking up this new XP-G2 version of the LD12 was the concern expressed here on cpf about a pulse width modulation (PWM)-like "flicker" on this model (see this thread for example). I provide a detailed explanation of the reoccurring signal issue in the Oscilloscope section of this review. Simply put, it is not PWM, but it is potentially detectable as a perceptible visual flicker on some modes on my sample (although it doesn't seem to be as noticeable as PWM would be at those same frequencies and output levels). I know there is a lot of confusion on this point, so I recommend you scroll down to post #2 for more info on what PWM actually is.

    If I were to hazard a guess, there is probably some component on the LD12 circuit that is not reliably performing to expected specs, and this is generating some variable degree of interference/noise. I've seen other examples of this before (even on current-controlled lights), although usually not so prominent. I also know from speaking with manufacturers in the past that these things can be hard to track down. In any case, I will send Fenix customer service a link to this review. Hopefully they will be able to isolate and correct the issue soon.

    One challenge in these cases is that individual samples tend to be quite variable in their presentation of interference/noise. I have no idea how representative my one sample is - but there seems to be a number of flicker reports here specifically for the XP-G2 version of the LD12. If you have a sample with a visual flicker, I suggest you contact your dealer and/or Fenix to see if you can come to a satisfactory resolution. Personally, I wouldn't consider noticeable visual flicker acceptable in a current-controlled light.

    Performance-wise, I am happy to report that this signal issue doesn't affect runtime - my LD12 performs as a current-controlled light should, with very good output/runtime efficiency. In terms of the minor fluctuations I saw in in output and runtime initially, those were fully resolved by a thorough cleaning. As always, this is the first step I recommend if you find any output fluctuations when running a light. But it is a little disconcerting to find a light needs contact cleaning right out of the box.

    I haven't done detailed beam testing, but the beam pattern is what you would expect for a light with this size smooth reflector, driven to these levels.

    I hope you found the detailed testing comparisons in this rather long "mini-review" useful.

    -----

    LD12 purchased from a local dealer.
    Last edited by selfbuilt; 10-25-2013 at 08:37 AM.
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  2. #2

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    What is PWM?

    I know a lot of people find the concept of pulse width modulation (PWM) unclear. While it can certainly produce a visual "flicker", it is not the only means by which that can happen.

    To put it simply, there are two general ways to reduce the output level on modern flashlights – current control, and PWM. Note that I am ignoring resistor-based methods, as they are pretty passé now. This is also going to be an extremely simplified explanation, but here goes …

    With current control, the actual current flowing into the emitter is reduced. This naturally results in lower output, and is typically an extremely efficient output control method (as emitters are generally more efficient at lower drive currents than higher ones). Note that it can be difficult to stably produce ultra-low moonlight modes this way, and you tend to get a warm tint shift on emitters when under-driven. Fenix is historically a master of current-controlled circuits, and their lights have always had some of the best runtimes in their respective output classes.

    The competing method is pulse width modulation (PWM). In this case, the current flowing into the emitter is rapidly turned off and back on at the max output drive level – but at an incredibly fast rate. Think of it as a very fast strobe – on the order of hundreds to thousands of times a second. Due to the phenomenon of the persistence of vision, you typically can't see these fluctuations – instead you perceived a dimmer overall level of light. The reason it is called PWM is that the only characteristic that changes is the width of the pulse (i.e., how long it is on during each constant cycle). The overall frequency of switching remains constant (as does the amplitude, since it's always max or off). The pulse width is also referred to as the duty cycle, as it is the relative proportion of time during each pulse that the light is on that determines the relative perceived output level (e.g., a 10% on-time during the pulse would seem as bright as ~10% of max output).

    The advantage of PWM is that it can provide very precise control of output – which facilitates ultra-low levels, and the extensive range of outputs in "infinitely variable" or "continuously-variable" lights (which typically just have a lot of discrete levels that look continuous). And because the emitter is always running at full power when on, there are no tint shifts to worry about. PWM does have a couple of downsides though – it is typically not as efficient as current-control for the same relative output level (since the emitter is always driven to max when on, and there is circuit overhead required with the rapid switching). More significantly, some people are sensitive to perceiving a "flicker" or stroboscopic effect when the PWM frequency is relatively low.

    I have no good data on what the "typical" human perception level for flicker is. It would appear that I am personally rather sensitive to it, as I can detect PWM flicker visually at frequencies up to about 2 kHz or so – unaided with any instrument or device. Beyond that, I can typically see no sign of it – except maybe when shining on a fast fan or raining water (two good ways to detect the stroboscopic nature of PWM). Note that it is rare to see such high PWM rates though, as there is an additional efficiency hit with switching that frequently.

    In the main LD12 review above, I show oscilloscope traces of something that is clearly not PWM. For a comparison of what PWM actually looks like, here are some examples from my Xtar R30 review.

    Xtar R30 Lo:


    Xtar R30 Med:


    Xtar R30 Hi:


    Note: I am not showing the Turbo (max) mode, as there is no signal there.

    This is a classic PWM pattern of increasing pulse width as the relative output level increases – with a constant frequency of 500 Hz. Personally, I find this particular frequency to be very visible by eye (i.e., noticeable flicker).

    Also, by definition, that there is always no PWM on the Max mode of a given light (i.e., the lower modes are all based on full power max). I have seen only a couple of exceptions to this rule in all my testing - and both were in cases where there were dual circuits in the head and tail that needed a regular pulse cycle to communicate with each other. The LD12 has a (weak) signal on Turbo, again inconsistent with PWM.

    Personally, I won't use a light with visual flicker, as I find it too distracting. But note as well that the perception of PWM flicker seems to increase as the duty cycle drops (i.e., 1% on-pulse width is a LOT more noticeable than 99% on-pulse width). You will thus find it more noticeable on lower output modes, with their concomitant low duty cycles. As an aside, this may be why I find the periodic sine wave-like signal on my LD12 Med mode less noticeable than actual PWM at that frequency (i.e., a <25% "on" duty cycle with complete on/off switching is apparently more visually noticeable that ~50% gradual sine-wave switching at that same frequency).

    Sorry for the long exposition, but I felt it was important for people to realize the difference between various types of output control methods and potential circuit signals. All this to say that my LD12 sample is indeed still a current-controlled light – but one with an oscillating signal that may potentially be visible to some people (as discussed in the main review).
    Last edited by selfbuilt; 10-18-2013 at 10:42 AM.
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  3. #3

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Some time ago, your prolificacy inspired me to ask jokingly if Canadian days have 25 hours. Today, the appropriate question seems to be whether the word ”mini” is a synonym for comprehensive in the Canadian variety of English.

  4. #4
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    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    With Fenix pushing the drive level to the LED down for longer runtime, can High mode work with an alkaline cell?
    Traditionally only low/medium [with 1 cell] could deliver a significant portion of the runtime in flat regulation.
    So 75-80% of an Eneloop's 200 minutes would be a yes for me.

    Looking back at the LD20 xp-g R4 review, that high mode lasted 2:25 on alkalines, that is the target runtime I hope Fenix can deliver.
    Last edited by MichaelW; 10-18-2013 at 12:36 PM. Reason: looking back

  5. #5

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Quote Originally Posted by Swede74 View Post
    Some time ago, your prolificacy inspired me to ask jokingly if Canadian days have 25 hours. Today, the appropriate question seems to be whether the word ”mini” is a synonym for comprehensive in the Canadian variety of English.
    Haha, yes, I guess it does require an explanation.

    I am experimenting with doing "mini" reviews of some lights that I pick up, where I pare down the details in the review. Specifically, skipping the detailed manufacturer specs table (since these can be looked up online), simplifying the build discussions and pics (since most of that is covered in my videos), skipping beamshots when the light doesn't look any different from others in its class, and limiting runtimes to just the most common rechargeable format.

    The LD12 is my first attempt at such a "mini" review - except the oscilloscope results sent me down a long explanatory path! Then I figured I might as well explain PWM a little more, and things just kind of snowballed from there.

    Rest assured, my regular reviews will continue with all sections intact ... but I hope to do some simpler lights in the mini-review format.

    Quote Originally Posted by MichaelW View Post
    With Fenix pushing the drive level to the LED down for longer runtime, can High mode work with an alkaline cell?
    Traditionally only low/medium [with 1 cell] could deliver a significant portion of the runtime in flat regulation.
    That's a really good question, it would be interesting to see how it does on alkaline.

    Ok, so much for my mini-review. I'll do a Turbo mode alkaline and report back.
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    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    No, no no. Turbo sucks with alkaline, we already know that. That high mode of claimed 65 lumens might/should be flat regulated at room temperature.
    But if you have 45 minutes to kill... out your 25+ hour day.

  7. #7

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Thank you for the detailed review! I am glad that you cleared up the PWM question for us.

  8. #8

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Quote Originally Posted by MichaelW View Post
    But if you have 45 minutes to kill... out your 25+ hour day.
    Yeah, yeah, I'll do both the Hi and Turbo on alkaline. Should hopefully get to it tomorrow.
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  9. #9
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    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Thank you for the review I ordered one about two weeks ago and I hope it will arrive next week. I've always liked Fenix lights and here some topics made me worry a little, but still, the 1xAA factor and the long run times made me choose it.
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    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    I wonder why the flickering, mistaken by many to be PWM, only seem to be reported on the LD12 G2 and not the LD22 G2.

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    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    I have LD22 G2, but actually didn't notice any flickering. Will check it out later. Anyway I like my LD22, the tint is nice cool white(no hint of bluish or greenish.
    Last edited by Swedpat; 10-19-2013 at 10:15 AM.
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  12. #12

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Quote Originally Posted by phosphor View Post
    I wonder why the flickering, mistaken by many to be PWM, only seem to be reported on the LD12 G2 and not the LD22 G2.
    Hmmm, don't know if this issue is restricted to just the LD12 XP-G2 circuit. It may be that there simply aren't as many LD22 XP-G2s out there in comparison. Or it may be that the LD22 circuit differs from the LD12 in some critical component. Of note, the original XP-G version of the LD12 didn't have any reported issues either - it was on the XP-G2 version (suggesting some other component issue change).

    Circuits are complex things. Although we tend to think of them as consolidated entities, the fact is that they contain a great many individual components. And the performance of those components - in interaction with all the others - is where problems can crop up. Sometimes even something as "simple" as board layout and trace locations can contribute to problems. In this case, I suspect it is a component that is not reliably performing up to spec (which can be highly variable, and hard to troubleshoot).
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  13. #13
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    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    parasitic drain?
    S.O.S. - Really? Seriously?!

  14. #14

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Quote Originally Posted by bhds View Post
    parasitic drain?
    No, there isn't any. The LD12 uses a physical clicky switch for on/off. There is no standby off mode, so there is no standby parasitic drain.

    As promised, here is my runtime update:




    I think the runtimes speak for themselves - the LD12 again shows improved output/runtime efficiency over my LD10 (with its lower output bin XP-G R4). Whether it meets your needs for runtime at a particular level, that's your call.
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  15. #15
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    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Even though the performance on High was less than I was hoping for, unless the room temperature of Canada is 10C I doubt anyone can visually tell that the output is dropping during the first 95 minutes.
    If you only use Turbo for 20 minutes at a time... and rest for an equal, if not greater length of time. Or just use rechargeable/lithium.

    Thanks Selfbuilt

  16. #16

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Quote Originally Posted by MichaelW View Post
    Even though the performance on High was less than I was hoping for, unless the room temperature of Canada is 10C I doubt anyone can visually tell that the output is dropping during the first 95 minutes
    That is right - you will not be able to see that kind of minute drop in output over time on the Hi mode run (in any country).
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  17. #17

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    On my LD12, very occasionally, hi mode is replaced by turbo. (low-med-turbo-turbo) .....

    It happened once while keeping change mode for 2 minutes .

  18. #18
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    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    wow...Thanks for the great review as usual...For the price and the issues I noted (no tail standing, flicker, low level output on high, no 14500 support amongst others) this is a light to be forgotten! This is of course just my opinion.

  19. #19
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    Smile Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Great review! Not to sound stupid here, but why don't you want PWM.
    That was also interesting the older model put out more light then the newer one.

  20. #20
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    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Am I reading the output summary chart correctly, the LD12 max output is only 5 lumens more than the E11?
    S.O.S. - Really? Seriously?!

  21. #21

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Quote Originally Posted by bhds View Post
    Am I reading the output summary chart correctly, the LD12 max output is only 5 lumens more than the E11?
    Yes, but that's not surprising - my E11 is rated by Fenix as 115 lumens, and my LD12 is rated as 125 lumens.
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  22. #22
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    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Quote Originally Posted by selfbuilt View Post
    Yes, but that's not surprising - my E11 is rated by Fenix as 115 lumens, and my LD12 is rated as 125 lumens.
    The search continues for a upgrade/replacement for my E11. Thanks Selfbuilt.
    S.O.S. - Really? Seriously?!

  23. #23
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    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Quote Originally Posted by Lovebryan24 View Post
    Great review! Not to sound stupid here, but why don't you want PWM.
    That was also interesting the older model put out more light then the newer one.
    PWM is a negative to many users cause of a few reasons. In some cases in can produce visible flicker (though better PWM drivers can avoid this for most users) and the efficiency is noticeably lower. Take for example the recent revision of the Olight i3, it switched from PWM to current controlled and got huge increases in runtime on lower modes (much more than the XP-G to XP-G2 upgrade would cause). PWM does have an upside though; it tends to reduce tint shift at lower levels.

  24. #24

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Quote Originally Posted by Lovebryan24 View Post
    Great review! Not to sound stupid here, but why don't you want PWM.
    That was also interesting the older model put out more light then the newer one.
    Actually, regulated max output is about the same between my LD12 and LD10. It is just that initial output that had marginally higher, on NiMH.

    As for benefits/drawbacks of PWM, that is covered in other threads here on cpf. And in any case, it is not relevant to this review, since none of these Fenix lights use PWM. The question here is really about flicker presence.
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  25. #25

    Default Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Selfbuilt, I didn't see your usual chart (well usual for the last year or so) comparing the spec lumens for each mode to your estimate. I found this to be one of the most useful charts since some of the specs can be way off, and well, we probably use the lower modes on our lights the most often.

    Also, the LD12 seems somewhat short on it's runtime specs, do you think it would meet its runtime on the "spec'd" 2500 mah cell (not sure it provides a full 25% bump over a 2000mah) and using a 10% output ANSI cutoff?
    Last edited by reppans; 10-23-2013 at 06:07 AM.

  26. #26

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Quote Originally Posted by reppans View Post
    Selfbuilt, I didn't see your usual chart (well usual for the last year or so) comparing the spec lumens for each mode to your estimate. I found this to be one of the most useful charts since some of the specs can be way off, and well, we probably use the lower modes on our lights the most often.

    Also, the LD12 seems somewhat short on it's runtime specs, do you think it would meet its runtime on the "spec'd" 2500 mah cell (not sure it provides a full 25% bump over a 2000mah) and using a 10% output ANSI cutoff?
    So much for my mini review. Ok, I will add the output table tomorrow.

    For the runtimes, it is true the specs seem slightly inflated, even with the higher capacity cells. It's not a huge variance. I would say the performance seen on my sample is very good - but not outstanding - for a control current circuit. Meeting those specs would certainly be a sign of excellence.

    But again, you have to take this as the n=1 sample it is - average performance could be higher than this one sample.
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  27. #27

    Default Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Quote Originally Posted by selfbuilt View Post
    So much for my mini review. Ok, I will add the output table tomorrow.

    For the runtimes, it is true the specs seem slightly inflated, even with the higher capacity cells. It's not a huge variance. I would say the performance seen on my sample is very good - but not outstanding - for a control current circuit. Meeting those specs would certainly be a sign of excellence.

    But again, you have to take this as the n=1 sample it is - average performance could be higher than this one sample.
    Crud.. I missed the "Mini" in the title, certainly don't need to do this on account of me (although I think that chart might be one of your most important to your readers, and least time consuming), so your call.

    Interesting comment on sample variation... do you find significant variations between different samples of the same light (Olight S15 case excluded)? I have multiple copies of a few lights and meter the lumen outputs to very consistent, but generally do not test runtimes between the different samples of the same light.

  28. #28

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Runtime variation is greater than output variation between samples, by far. That's because more variables are at play (e.g., Vf of the emitter will influence runtime, but is irrelevant for output).

    This is especially true at low drive currents, it seems. Another reason why I don't do extended low mode runtime tests - the results are impossible to interpret without a measure of variation. Hi modes are a lot more consistent.
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  29. #29

    Default Re: Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    As promised.

    Full list of all my reviews: flashlightreviews.ca. Outdoor 100-yard Beamshots 2011. Latest: Olight M18 Striker.
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  30. #30

    Default Fenix LD12 (1xAA, XP-G2 R5) Mini-Review: RUNTIMES, OUTPUT MEASURES, VIDEO.

    Thanks Selfbuilt, great info on both accounts, much appreciated!

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