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Thread: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more!

  1. #1

    Thumbs up Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more!

    Warning: pic heavy, as usual.




    The SC52 is the latest refresh of the Zebralight line of 1xAA lights. I recall reviewing the very first Zebralight model ever produced – the 1xAA H50 (XR-E) – some five years ago now. That was more of a headlamp model though, and was followed eventually by the traditional forward-facing SC50 (XP-E) and eventual SC51 (XP-G).

    The new SC52 is a XM-L-based model, with a revised build and greater output. Let's see how it compares to the earlier models, and the competition.

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

    • LED: Cree XM-L Cool White (Nominal CCT 6300K)
    • User Selectable Levels: 3 main levels (High, Medium and Low). Each main level can be programmed to one of its two sub-levels. The second sub-level of the each main levels can be further programmed to different brightness levels or strobes.
    • Light Output:
    • High: H1 280 Lm (0.9 hrs) or H2 172 Lm (1.7 hrs) / 108 Lm (3 hrs) / 4Hz Strobe
    • Medium: M1 50 Lm (7.5 hrs) or M2 25 Lm (12 hrs) / 12 Lm (27 hrs)
    • Low: L1 2.7 Lm (4 days) or L2 0.34 Lm (3 weeks) / 0.06 Lm (2 months) / 0.01 Lm (3 months)
    • Light output are ANSI out the front values. Runtime tests are done using Sanyo 2000mAh Eneloop AA batteries. Light output with 14500 batteries are the same except that the H1 is 500Lm for the first minute and then steps down to 280Lm.
    • Operating Voltage Range: 0.7V - 4.2V
    • Battery: One 1.5V AA (NiMH, lithium or alkaline) or 3.7V 14500 Li-ion battery. Batteries are not included in the package.
    • Parasitic Drain: Negligible (equivalent to 16 years, much less than the self discharging of a battery)
    • Automatic stepping down when battery (AA and 14500) capacity is low
    • Built-in over-discharging protection for 14500 batteries (2.8V cutoff)
    • Electronic soft-touch switch, with a 200,000 cycle operating life
    • Smart user interface provides fast and easy access to all brightness levels
    • Precision machined unibody casing from premium grade Alcoa aluminum bar stocks
    • Proprietary heat sinking design bonds the LED board directly to the unibody aluminum casing
    • Durable natural hard anodized finish (Type III Class I)
    • Tempered optical grade glass
    • Preinstalled bezel down pocket clip
    • Orange peel textured reflector
    • Anti-roll and tail-standing capable
    • Battery power can be locked out by slightly unscrewing the tailcap to prevent unwanted activations or parasitic drain
    • Beam Type: 80 degree spill, 12 degree hot spot
    • Dimensions: Diameter: 0.93 inch (23.6 mm), Length: 3.08 inch (78.2 mm)
    • Weight: 1.4 oz (40 gram)
    • Waterproof to IPX7 (2 meters, 30 minutes)
    • Accessories: two o-rings
    • MSRP: ~$64
    Operation:
    • This light has 3 main levels (High, Medium, and Low). Each main level can be programmed to one of its two sub-levels. The second sub-level of each main levels can be further programmed to different brightness levels or strobes.
    • Basic Operation
    • Short click turns on the light to High or turns off the light.
    • Long click (press and hold for about 0.6 seconds) turns on the light to Low.
    • Advanced Operation and Configuration
    • Short click turns on the light to High. Short click again quickly to cycle from High to Medium, and Low.
    • Press and hold to cycle from Low, Medium and High, release to set. When press and hold, the light always cycle from Low to High regardless which level you are currently in.
    • Double click to toggle and select between the two sub-levels for that main level. Sub-level selections (except the strobe) for the 3 main levels are memorized after the light is turned off and through battery changes.
    • The second sub-level of each main levels can be configured after 6 double clicks. Double click (startng with the 7th) to cycle and select different brightness levels or strobes. Short click to turn off the light when finishing configurations. The selections for the second sub-levels are memorized after the light is turned off and through battery changes.
    • This light uses the main LED (flashing 1 to 4 times) to indicate the estimated remaining capacity of the battery. To start the battery indicator, (from Off) short-click 4 times without pause.



    The SC52 came in the standard "eco-friendly" packaging that has been standard on Zebralight for some time now. Included in the simple (but firm) cardboard box was the light with removable clip (attached, with screws), two extra o-rings, a one-page instruction sheet, and a notice about battery use.




    From left to right: Duracell AA NiMH; Zebralight SC52, SC51; Foursevens Mini AA, Quark AA; Sunwayman V11R+AA extender; Nitecore EA1, SENS AA, MT1A; Rofis JR-12.

    All dimensions are given with no batteries installed:

    Zebralight SC52: Weight 39.5g, Length 79.0mm, Width (bezel): 22.6mm, Width (max) 25.4mm
    Zebralight SC51: Weight: 37.4g, Length 80.5mm, Width (bezel) 21.1mm, Width (max): 22.6mm
    Nitecore MT1A: Weight: 54.6g, Length: 104.6mm, Width (bezel): 22.7mm
    Nitecore SENS AA: Weight: 26.1g, Length: 82.7mm, Width (bezel): 19.8mm
    Nitecore EZAA: Weight 20.9g, Length: 85.0mm, Width (bezel) 16.6mm
    Rofis ER12: Wright: 35.5g, Length: 96.2mm, Width (bezel): 18.6mm
    Tiablo E2A: Weight: 45.7g, Length: 101.2mm, Width (bezel): 19.9mm
    Xeno E03:: Weight: 48.1g, Length 96.7mm, Width (bezel): 21.5mm
    Xtar WK25B: Weight 42.9g, Length: 102.3mm, Width (bezel): 22.5mm

    The SC52 is slightly shorter overall than the SC51 (which is impressive, given that it also has a deeper reflector and greater height clearance for longer 14500 cells, compared to the SC51).






    The overall build design is similar to the earlier SC5x series lights. The most obvious changes are the slightly fatter head and the ridges along the body of the light. I definitely find the SC52 "grippier" than the predecessor SC51/SC50, which were a little too smooth in my view.

    Anodizing remains the typical Zebralight "natural" finish (which is a bit more gray-green than most). Note that natural anodizing can be highly variable (e.g., my sample seems lighter colored than most Zebralights I've had).

    Zebralight has finally started adding model labels to this series (previously, there were absolutely no identifying labels of any sort on SC50/SC51). The "Zebralight SC52" body label is applied to a a cut-out from the ridge detail, and is very legible.

    As before, the SC52 still has a flat-bottomed tailcap (slight indentation now) and an electronic control switch in their head. The switch cover has a revised textured grip, and is more recessed than previously. It also has a firmer switch feel, requiring a more definite click to activate. Taken together, these features should help reduce accidental activations even further.

    Tailcap threads are anodized as before, allowing for tailcap lockout. This is important on all lights with electronic switches, since there is always some parasitic stand-by current drain to allow the switch to function (scroll down for a discussion in this case). Threads seem of comparable size and thickness to the earlier SC51.

    The light can both tailstand and headstand.

    The light comes with a removable metal pocket clip, held in place by two regular Phillips head screws.




    As before, the light has a flat stainless steel bezel ring - but the head is wider now, with a wider and deeper reflector on the SC5. Reflector also seems to be less heavily textured than before (at least on my sample, which I would consider a light orange peel – LOP). The cool white XM-L emitter was well centered on my sample.

    User Interface

    The Zebralight SC-lights have always had a fairly unique user interface. While it may sound a little complex when first described, it is actually quite easy to use. The SC52's interface has been tweaked and expanded slightly from the SC51, but will feel familiar to those used to Zebralight.

    On/off and mode switching is controlled by the electronic clicky switch.

    Basic Operation

    From Off, a quick-click (rapid press-release) of the switch turns the light on in Hi. If you repeatedly quick-click without much of a pause, the light will advance to Med, then Lo with another quick-click.

    A slightly-sustained press-hold-release (hold greater than 0.6 secs) turns the light on in Lo. If you hold the switch longer, the light will advance through Med and then Hi, in a repeated Lo > Med > Hi sequence, until you let go of the switch to select the level you want.

    At any time when On, press-and-hold to start the Lo > Med > Hi ramp.

    A quick-click turns the light off.

    Advanced operation

    In regular usage, there are 6 possible output modes that are easily accessible, arranged in two sets of Lo/Med/Hi levels – the primary Lo/Med/Hi, and a sub-level set. Note that you can program the second sub-set (as explained in the section below).

    To switch to one of the secondary Lo/Med/Hi sub-levels when on, double-quick-click the switch in any given level (e.g., in primary Med, double-click to go to the sub-level Med). The light will remember the selection of which Lo/Med/Hi level was last used, and return to that level the next time it is access (from Off, or as part of the ramp).

    For convenience sake, Zebralight refers to the primary levels as L1, M1, and H1, and the secondary sub-levels as L2, M2, H2.

    Programming the sub-levels

    For the secondary sub-levels, you can actually choose from multiple choices. The primary levels are fixed.

    For L2, you have the choice of three different levels. For M2, you have the choice of two different levels. For H2, you have the choice of two different levels or strobe mode (note that the strobe option can't be memorized as part of the standard operation). For the sake of clarity in my tables and graphs, I have referred to the programmable constant-output modes as L2A/L2B/L2C, M2A/M2B, and H2A/H2B. End result is that you actually have 10 defined constant outputs available to you, plus one strobe mode.

    To program your desired secondary sub-level, double-click 6 times in any given level. Subsequent double-clicks will now alternate you between your various choices for that sub-level (e.g. M2A > M2B, in repeating sequence). To select the desired secondary sub-level, turn the light off by a single quick-click. When you next access that level, it will be saved to your programmed choice.

    I realize the programming above may seem complicated, but you can safely ignore it all and simply use the light in basic mode as a 3-stage light. Or for that matter, as a 6-stage light in two sets of 3.

    Video Overview:

    For information on the light, including the build and user interface, please see my new 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.

    PWM

    There is no sign of PWM that I can see, at any output level – the SC52 is fully current-controlled, as claimed.

    Note that the early SC51 had PWM on some of the lower levels (although I believe this was eventually replaced with current-control on that model as well). I am glad to see the SC52 is fully current-controlled right out of the gate.

    Some users have reported seeing a brief flicker or pulse on the lowest possible output level (i.e. L2C, in my terminology). But I have not noticed one on mine – it seems perfectly stable, on all batteries.

    Strobe:



    The "hidden" strobe is a relatively slow 4 Hz (i.e., more of a signalling strobe than a tactical one).

    Standby Drain

    A standby current drain is inevitable on the SC52, due to the electronic switch in the head. Here is how the new SC52 compares to the earlier SC50 and SC51:

    SC52: 129.1 uA on 14500, 20.2 uA on Eneloop NiMH
    SC51: 41.8 uA on 14500, 14.2 uA on Eneloop NiMH
    SC50: 7.4 uA on 14500, 2.3 uA on Eneloop NiMH

    While there has been an upward trend in standby currents over time on the SC5x series, these values for the SC52 are still quite low in absolute terms. Assuming a standard 900mAh protected 14500, and a 2000mAh Eneloop NiMH, these currents would translate into 9.5 months on 14500, and 11.3 years on Eneloop.

    Certainly, the drain is absolutely nothing to worry about on NiMH. The drain is higher 1x14500 (but still not unreasonable). But as always, I recommend you lock-out the light when not in use.

    Flicker Issue on 14500

    Some users have also reported flickering issues on Max on 14500, but this effect can be inconsistent. Note that the only difference in output between 14500 and NiMH/alkaline is the max mode (H1) runs at a higher level on 1x14500 initially (i.e., 500 lumens). After 1 min, the light steps down to typical max mode level for standard batteries (i.e., 280 lumens). The flickering, when observed in my case, has been on this first minute of 500 lumen output only.

    There has been some speculation here as to whether this is due to different 14500 chemistries, voltage or heat. I can confirm that on my one sample, it is fact dependent on BOTH battery voltage and heat.

    To explain, let me show you an oscilloscope trace for the first 65 seconds of runtime - on a fully charged AW protected ICR 14500 (~4.19V right off the charger), in my standard runtime testbed with a cooling fan.



    Ok, not much to see here – the first spike shows the light On signal at time=1 sec, and the second spike is the step-down to the standard H1 level at t=60 secs.

    Not let's try it again without any cooling applied:



    Starting ~6 seconds after activation, the light begins flickering – at a rapidly accelerating rate. This rapid flickering continued until the light stepped down at 60 secs – at which point it ceased immediately.

    How about a slower spinning fan?



    Ok, now you see the flickering doesn't start until much later (~20 secs in), and is much more infrequent (i.e., slowly accelerating). I increased the fan speed to my typical level after ~35 secs, and you can see the flickering stopped immediately.

    On the basis of the above, you could reasonably conclude that the flickering is mediated solely by relative heat (i.e., with sufficient cooling, you can prevent it from occurring).

    But here's where it gets interesting – if I re-run the test with a partially depleted cell (~4.09V according to my DMM), with no cooling applied, I get this:



    Ok, now all you see are a few flicker spikes starting at the very end the first 60 secs 500 lumen level (which again ceased immediately with step-down). Note again, there is NO cooling applied to run above.

    Note also that the actual output above is no different from the earlier runs (i.e., the 4.09V battery is giving the same ~500 lumens as the 4.19V battery did). So this tells you that the effect cannot be due solely to heat (i.e., the heat in the situation above should have been the same as the earlier no cooling trace, given that the outputs were the same).

    It therefore seems that there is some sort of circuit issue whereby the light responds to high heat only if the 14500 is near max capacity. On my sample at least, these two variables are intertwined – you can't say the light never flickers <4.1V (it can – but only mildly without cooling), and you can't say it always flickers >4.1V (depends on the level of cooling).

    I'm not quite sure what to make of all this, and have queried it with Zebralight. They have responded to me that they are aware of the issue, and are working to resolve it. When I hear more, I will update this thread. In the meantime, if you are finding a similar issue on your SC52, I recommend you either drain some capacity off your freshly-charged 14500 cells, or contact your dealer about a replacement.

    Beamshots:

    All lights are on Max output on Sanyo Eneloop AA NiMH. Lights are about ~0.75 meter from a white wall (with the camera ~1.25 meters back from the wall). Automatic white balance on the camera, to minimize tint differences.













    1x14500 (AW Protected 14500) Li-ion Comparison:









    Beam pattern is as you would expect for a XM-L light with this size reflector – a fairly big hotspot and decent sized spillbeam. Scroll down for full output details in my tables.

    Testing Method:

    All my output numbers are relative for my home-made light box setup, a la Quickbeam's flashlightreviews.com method. You can directly compare all my relative output values from different reviews - i.e. an output value of "10" in one graph is the same as "10" in another. All runtimes are done under a cooling fan, 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 ANSI/NEMA FL-1 Standard page for an explanation 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).





    As you can see above, the SC52 has class-leading output – for both standard AA and 14500 Li-ion. The max output on 1xAA is particularly impressive. Throw is reasonable, given the size of the reflector.

    Since I don't have a lot of comparator data on other 1xAA XM-L lights, here are some summary tables for recent 2xAA and 1xCR123A/1xRCR lights I've recently tested (mainly XM-L-based). You can directly compare the output and throw values for the SC52 in the tables above to the tables below.



    The SC52's ~290 estimated ANSI FL-1 lumens on max puts it a bit under most of the max outputs of the newer XP-G and XM-L 2xAA lights I've tested. That's to be expected, given that it is easier to have a sustained power draw from 2x AA cells in series than it is a single AA (i.e., you can't drive a 1xAA light as hard).



    A similar pattern can be observed for most the 1xCR123A lights – typically, these have fairly similar max outputs to 2xAA lights.



    On 1xRCR, the better comparable would be the ~540 estimated ANSI FL-1 lumens I get on the SC52 on 14500 Li-ion. That puts the SC52 in much the same category as many of the recent 1xRCR lights I've tested. This is as you would expect, as there is effectively no real difference between RCR and 14500, except perhaps greater runtime/capacity on some 14500s.

    Lumen Estimate Summary

    As with a number of my recent reviews, here is a summary table showing what my ANSI FL-1 lumen estimates are for the SC52:



    Zebralight's reported ANSI FL-1 lumen specs seem pretty consistent with my output estimates (although my estimates seem to be a bit higher at the high end, and a bit lower at the low end). Part of this may simply be variability from one light sample to the next (e.g., it is hard for manufacturers to reliably reproduce the same sub-lumen levels in every light).

    I know there's been some discussion here as to the accuracy of various lumen estimates. To expand on this in the case of the SC52, I have done some additional detailed comparisons to a Fenix light in post #2.

    Output/Runtime Comparison:

    Let's start with standard AA cells (NiMH Eneloop, alkaline, and Energizer L91 lithium):










    Ok, there's a lot of data up there.

    The general take-home message is that the SC52 is a real output AND efficiency leader on standard cells. A second point is that the SC52 is typically quite well regulated (i.e. flat-regulated) on standard cells, except on max output (especially on alkaline, as expected).

    It is particularly impressive to see how long the SC52 runs on the Med-Hi levels, compared to equivalent output levels on other models. To help you compare to the Zebralight specs, here is a table comparing runtimes to the ANSI FL-1 standard of time to 10%:



    Like with the Zebralight lumen output specs, the ANSI FL-1 runtimes seem fairly consistent with my testing as well.

    As always though, I recommend you actually look at the full runtime graphs for more info on output level changes over time. Given the range of possible regulation patterns, it is important not to get fooled by looking at just two (rather arbitrary) points from the ANSI FL-1 standard – the full graphs tell you infinitely more (as I explain on my Testing Methods page).

    1x14500:




    On 14500 Li-ion, overall output/runtime efficiency of the SC52 is good, and seems pretty much in keeping with other lights in this class. However, the SC52 again shows very flat-regulation – which not all of the other lights were able to maintain.

    As shown in my output summary table in the preceding section, Zebralight has also done an excellent job keeping output levels consistent between standard cells and Li-ions. The only real difference is on max (H1), where the SC52 shows a higher initial output for 1 min, before stepping down to the standard cell H1 level.

    Normally that would be the end of my runtime comparisons, but I have been asked to show how the SC52 compares to other classes of lights. I provided summary tables for 2xAA, 1xCR123A and 1xRCR in the preceding section, and thought I would include 2xAA below (given the comparable battery chemistry).

    2xAA Lights:
    (NOTE that the SC52 is a 1xAA light, and all the others below are 2xAA!)










    A couple of points strike me in this comparison of the 1xAA SC52 to the 2xAA lights. The first is that max output of the SC52 is not that much lower than the 2xAA lights – but standard cells get exhausted quickly at this level. You can really see this on the alkaline graph – there is simply no way that a 1xAA light is going to be anywhere near competitive to a 2xAA light on max drive levels on alkaline.

    The second point is that the very high efficiency of the SC52 on its Med levels gives it the opportunity to compete fairly well with a lot of the 2xAA lights. No, it doesn't run quite as long for comparable output, but it is surprisingly close for a 1xAA light. Again though, you are best to run the light on NiMH or L91 lithiums to see the best performance here.

    UPDATE FEBRUARY 1, 2013: Upon request, I've also plotted the max output of the SC52 against common XM-L-based 1xCR123A lights in my collection:



    Please note that I have plotted *BOTH* L91 lithium and NiMH Eneloop for the SC52 above. In my testing, many 1xAA lights show slightly lower max output on L91 than they do on alkaline or NiMH. I'm not sure why (maybe to do with voltage?), but it is a common observation I've noticed over the years. In the case of the SC52, I estimate ~290 ANSI FL-1 lumens on NiMH, and ~255 estimated lumens on L91.

    I suggest you compare the full curves for how the lights perform, but in general terms, the SC52 is toward the middle of the 1xCR123A pack for initial activation output levels on max. Of course, regulation on lithium-based CR123A cells is typically flatter than NIMH.


    Potential Issues

    Zebralights all use an electronic switch, and therefore require a small stand-by current when fully connected. The standby drain on SC52 is low enough on standard cells as to be completely negligible (i.e., would take over a decade to drain an Eneloop). However, on 14500, the drain is bit higher – enough to fully drain a cell in under one year. Note that you can always physically lock out the light at the tailcap.

    My SC52 sample had flickering issues at the "500 lumen" Max mode on 1x14500, with freshly-charged cells. As explained earlier in the review, this flickering disappeared <4.1V, and was highly dependent on the cooling state for Li-ion cells between ~4.1V and ~4.2V. I suspect there is some sample variability here, as only some users have reported similar issues near the 14500 max capacity level. Zebralight is aware of the problem, and working on a resolution - I will update this thread when I hear more.

    The SC51 was known to have accidental activation issues (i.e., when I carried it as an EDC, I found that the SC51 could turn on if something pressed against the switch in my holster/pocket). I have been carrying the SC52 for better part of a week now, and have had absolutely no accidental activations yet. It thus seems like the revised switch design of the SC52 (i.e., smaller button, more recessed, firmer press need to activate) is effective at ameliorating this previous issue.

    Preliminary Observations
    The SC52 is a very impressive update to the SC5x-series of 1xAA lights.

    I was impressed with the XP-G-based SC51 when it was first launched – especially with its class-leading max output and its extremely efficient runtime performance and good regulation pattern. It did have a few limitations though – no 14500 support, a rather smooth finish, PWM on lower modes (at least originally), and an annoying tendency toward accidental activation when carried as an EDC (typically on max!). I'm happy to report the SC52 has improved in all the above areas.

    Let's start with the output – the XM-L-based SC52 is again a new class leader on standard AA cells. Regulation pattern is excellent (i.e., perfectly flat on all levels except max), and output/runtime efficiency has reached an even new high for the class, at all levels tested. I don't know how Zebralight has managed to squeeze so much runtime out of their current-control circuit, at all levels now.

    The support for 14500 is appreciated, although there are a few quirks here. My sample showed a flickering issue initially on fully-charged 14500 during the ultra-Hi max output stage. This flickering was both voltage and temperature dependent, and was easily resolved by draining off a small amount of capacity from the freshly-charged cell first. Regulation on 14500 was excellent, with perfectly flat output at all levels (something a lot of other multi-power lights can't match). Overall efficiency was very good, in keeping with other good current-controlled lights (but just very good - not at the outstanding efficiency levels seen on standard AA batteries).

    I'm also glad to see that Zebralight appears to be quite accurate in their specs – including ANSI FL-1 output and runtime measures, according to my testing (see post #2 for an additional discussion of lumen estimation).

    Build-wise, I like the new "ribbed" body design, which improves grip. I also personally like the larger head – in fact, I'd like an even longer body (I have fairly longer hands and fingers, so can find overly small lights problematic for handling). The more recessed switch (with firmer feel) is also greatly appreciated – no accidental activations so far, when carried on my belt. This is what caused me to give up on EDCing the SC51, so I'm glad to see they have addressed it here on the SC52.

    So far, I'm not coming up with any negatives for the SC52, compared to its predecessor SC51. Beam pattern is bit more "floody" on the XM-L-based SC52 compared to the XP-G-equipped SC51, but peak throw remains pretty similar on max (thanks to the extra output).

    It is frankly amazing to see a 1xAA light than can – on standard batteries – nearly match the output of many 2xAA or 1xCR123A lights. Coupled with its outstanding efficiency and excellent regulation patterns the SC52 is a real competitor for these other classes, not to metion its own 1xAA class.

    ----

    SC52 was supplied by Zebralight for review.
    Last edited by selfbuilt; 02-01-2013 at 08:37 PM.
    Full list of all my reviews: flashlightreviews.ca. Latest hobby: whiskyanalysis.com. Latest flashlight review: Thrunite TN42.
    Gratefully accepting donations to my battery fund.

  2. #2

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    I've noticed there has been a bit of discussion around here as to how accurate Zebralight's ANSI FL-1 output ratings are. As this is a separate issue from the actual review, I thought I would do some analysis in a second post.

    As you can see from the summary table in my review above, my SC52 lumen estimates actually match the Zebralight specs fairly well. That said, I've also seen comments that my lumen estimate scale is inflated, compared to some sources. That's certainly possible, since my estimation method is based on a calibration of my lightbox to certain specific makers and testers (see my Lumen Estimation page for more information). If the lumen values for the group of lights used in that calibration were biased one way or other, than my estimation method would be similarly biased.

    But my key point has always been that it doesn't matter for relative output measures, as those remain consistent across all my reviews (i.e., regardless of the absolute value of the calibration, the relative relationships always hold consistently). I also recommend you don't focus on one arbitrary output time point (i.e., ANSI FL-1 30 secs), but rather look at the full runtime graphs for how relative output changes over time.

    In any case, I think that it is unlikely that there is a large systematic bias in the absolute values of my lumen estimates, given that I used what were generally agreed upon as reputable lumen sources for the calibration standard at the time (again, see the link above for details). In particular, Fenix was one of the sources used in my calibration, and their lumen measures were very consistent with the best-fit line of my own estimates (although this was based on their pre-ANSI FL-1 lumens). Note that I matched the time of lumen measurement as best I could, and gave priority to later time points where available (i.e., I only use initial activation maximums if that's all that was available for a given light). Looking at the recent results (including this review), there may be a slight inflation of my lumen conversion scale - but it's very hard to say without testing the lights in a proper integrating sphere.

    In this case, I have been asked to comment on how the SC52's lumen estimates match the Fenix LD20. I happen to have a LD20 XP-G R4, which was rated by Fenix as 205 lumens at the time. Let's start with my calibrated lightbox estimated lumens:

    SC52 Hi1 = 280 Zebralight lumens = 290 Selfbuilt Lightbox estimated lumens
    SC52 Hi2A = 172 Zebralight lumens = 190 Selfbuilt Lightbox estimated lumens
    Fenix LD20-R4 Turbo = 205 Fenix lumens = 205 Selfbuilt Lightbox estimated lumens

    EDIT: As jirik_cz points out below, this "205" from fenix was pre-ANSI FL-1. Unfortunately, I don't have any of their later LD20 lights, so don't how they would compare to this one. I would assume the LD20-R4 should have a slightly lower ANSI FL-1 lumen rating, but it's hard to know what that would have been. If we had true apples-to-apples ANSI FL-1 output lumen values, I suspect the LD20-R4 would probably be rated somewhere close to the SC52 Hi2A.


    Note that I also do ceiling bounce tests for all my lights, to give you an independent measure from my light box. I have just re-measured ceiling bounce results for both lights at 30 secs post-activation, using my NIST-certified Lux lightmeter:

    SC52 Hi1 = 290 Selfbuilt lumens = 55.5 lux ceiling bounce
    SC52 Hi2A = 190 Selfbuilt lumens = 36.5 lux ceiling bounce
    Fenix LD20-R4 Turbo = 205 Selfbuilt lumens = 38.5 lux ceiling bounce

    Now, the ceiling bounce numbers don't help you with figuring out absolute lumen estimates – but they again correlate fairly well for the relative relationships. In the example above, the LD20-R4 is 5.5% brighter than the SC52 Hi2A by ceiling bounce (consistent with my lumen estimates which say it is ~8% brighter). Similarly, the SC52 Hi1 is 44% brighter than the LD20-R4 on ceiling bounce (consistent with my lumen estimates suggest it is ~41% brighter).

    It's hard to demonstrate this visually, since our relative perceptions of output are not linear (see my discussion here of the power relationship that defines human visual output perception). Also, the differing beam profiles of the two lights introduce a huge confound to visual comparisons, as the LD20 has a narrow (and correspondingly brighter) spill, and a more "throwy" hotpsot (thanks to smaller XP-G emitter).

    Beamshots are an extremely limited aid in this regard, but here's a simple comparison of output of these two lights under various camera exposure settings. To facilitate visual comparison, I have moved the lights closer to the wall (to diffuse out the beams somewhat), and adjusted depth so overall spillbeam diameter is roughly similar (so you don't get fooled by a wider or narrower spill).











    Again, the lights are at different distances to the wall, to try and equalize the overall spillbeams to allow you to more easily compare overall output visually. This is distinct from all my other beamshots, which are a standard distance from the wall to allow you to compare different spillbeam widths. In any case, I think the above direct comparisons are consistent with what my lightbox and ceiling measures both report.

    So, by all measures at my disposal, it would thus seem that Zebralight's lumen values (for the SC52 at these levels) are at least pretty comparable to Fenix's lumen values, as well as my own lumen estimates. At least it gives you a way to calibrate your expectations.

    P.S.: Despite the above, I continue to recommend that people do NOT focus on max lumens estimates at the rather arbitrary time point of 30 secs post-activation (i.e. the ANSI FL-1 standard). It is far more important to pay attention to the actual output/runtime graphs, as these show you how the relative output changes over time. On max, a lot of Iights tend to drop off rapidly in output, or step-down after a couple of minutes. As such, you risk being misled if you simply look at ANSI FL-1 output and runtime values for a given light. I discuss the importance of comparing runtime graphs visually on my Testing Methods - Runtimes page on flashlightreviews.ca.
    Last edited by selfbuilt; 01-28-2013 at 09:22 PM.
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  3. #3

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Thanks for the SC52 review It is probably one of the most efficient AA lights on the current market.

    Quote Originally Posted by selfbuilt View Post
    In this case, I have been asked to comment on how the SC52's lumen estimates match the Fenix LD20. I happen to have a LD20 XP-G R4, which was rated by Fenix as 205 lumens at the time.
    LD20 R4 was rated at 205 lumens, but that was before Fenix adopted the ANSI standard. The next R5 model which used 7% more efficient LED was rated only 190 ANSI lumens, so the LD20 R4 was probably only around 177 ANSI lumens.

  4. #4

    Default Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more!

    Stellar Selfbuilt.. thank you so much for including 2xAA and 1xCR123 light data given that the ZL specs really compete in that realm. Also, thank you for addressing the lumen scale thing, I know I've been one of the voices behind it. Whatever the scale used, as you have mentioned, the important thing is that your data is consistent and relative, and so can be used as an accurate common base from which to compare between lights.

    Very, very much appreciated.

  5. #5

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Awesome review for an awesome light. Well done as always Selfbuilt

  6. #6
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    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Thanks SB for yet another excellent review, best ever.
    You really stepped outside the box and gave us some meat to chew on.
    Your runtime graphs truly give insight into how these lights work.

  7. #7

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Superb review. We are so lucky to have Selfbuilt and our other excellent reviewers.

    Regarding the light, solve the flickering issue and a total win.

    Spotted only one error: "Again though, you are best to run the light on NiMH of L91 lithiums to see the best performance here." ...Did you mean "or"...or is this a new hybrid batt? Lol...

    Well, been waiting for this review, guess it`s time to place my order. Dis is mine nixt lite. Soon as my dealer gets them back in stock...
    Last edited by Badbeams3; 01-28-2013 at 06:19 PM.

  8. #8

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    I'll add my voice to the other grateful readers and thank you for yet another detailed review of a very popular light. I too have been interested in the posts of some with flickering on H1 using fully charged IMRs/ICRs and had not noticed it with my SC52 until today when I popped a charged Sanyo based Intl' Outdoor 14500, 840mAh ICR and noticed that it dropped from H1 to L1 within seconds. No flicker just a drop-down. Oddly the battery level indicator only showed 3 flashes with this battery as well? Took it out and measured 4.07v. When the battery finally reached around 4v it functioned normally. Another exact same IO Sanyo battery as well as 7 other fully charged 14500s of diff brands function fine as well.

  9. #9

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Another great review. I know you don't normally do this but how hard does it work an AA battery? On the H51w, it is drawing around 2.2A-2.3A at the tailcap on an Eneloop and 2.5A on a Sanyo 2700. I found that the H51w was very fussy (i.e hard to get the highest mode) with a lot of NiMH AA batteries other than Eneloops.

  10. #10
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    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Nice Review, I like the runtime tests. I'm a little sad to see that this light is not that well suited to the Lithium cells when used on Hi. The SC51 is much better for EDC with Lithium primary in my opinion even if it gives up some brightness.

    From your analysis it looks to me that the flickering is totally from heat buildup probably on the regulator chip. I suspect your cooling is not effective enough to cool the circuit enough. The excessive heat appears to have two sources; the overall excess heat generated by the LED, and the excess heat created by the regulator itself when the input voltage is high. These two significant heat sources are contributing different amounts of heat in your various tests that exhibit the flicker issue, such that the temperature of the regulator circuit is too high.

    Amazing output for this light, I quite like mine but I don't have any 14500, I thought this light might be the first to make me buy a 14500, but I think I'll pass on that for now. Maybe by the time the 5K version ships, I am quite disappointed in the performance on the Lithium primary because if I was to EDC this light, that is the cell I'd want to use... I guess this one is Eneloop power for me. I was quite impressed with how well it did on Alkaline. It looks like they paid less attention to the Lithium and more to the Alkaline, NiMH, Li-Ion chemistries.

    Looks like there are some typos from cut and past in the legend for the Medium level graphs as the modes are still listed as HiA and HiB. I think I saw some other typos in the legeneds, but I forget now.

    Thanks for the extensive testing.

  11. #11

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Thanks for the support everyone, glad you are enjoying the review.

    Quote Originally Posted by jirik_cz View Post
    LD20 R4 was rated at 205 lumens, but that was before Fenix adopted the ANSI standard. The next R5 model which used 7% more efficient LED was rated only 190 ANSI lumens, so the LD20 R4 was probably only around 177 ANSI lumens.
    Thanks, a good point - ANSI FL-1 spec would certainly have been lower than max OTF lumens. Unfortunately, I don't have the later lights to directly compare in my lightbox, so don't know how they perform. But in my experience, a higher output bin does not always translate into a directly proportional increase in output (and conversely, a lower output bin may not be that much lower in output spec). Not sure why, but it likely involves a combination of effects of the circuit design and other LED characteristics (Vf maybe?). So while it would have been lower, it's hard to know what the ANSI FL-1 spec would have been for the R4 version (unless Fenix released that info at some point, for the older light?)

    As an aside, I should mention that my lumen estimation conversation method was based on a comparison of specific time points post-activation. I matched the time of lumen measurement as best I could, and gave priority to later time points where available (e.g. if I had specified 30 sec or 1 min post activation, I choose those over initial activation for the comparison). I only used initial activation maximums if that's all that was available for a given light. In any case, they were always matched to the same time point in my lightbox testing.

    Quote Originally Posted by reppans View Post
    Stellar Selfbuilt.. thank you so much for including 2xAA and 1xCR123 light data given that the ZL specs really compete in that realm. Also, thank you for addressing the lumen scale thing, I know I've been one of the voices behind it. Whatever the scale used, as you have mentioned, the important thing is that your data is consistent and relative, and so can be used as an accurate common base from which to compare between lights.Very, very much appreciated.
    Thanks. Yes, at the end of the day, I'll I can say is my relative scale is consistent over time. Even if it does seem slightly inflated, not sure there's much point in trying to come up with a new calibration - it would likely just create confusion between the "new" numbers and the "old". The consistency and backward-compatibility is more valuable in my mind than the absolute correlation.

    Quote Originally Posted by Badbeams3 View Post
    Regarding the light, solve the flickering issue and a total win.
    Agreed. Zebralight tells me they are working on it ... I'm sure they will sort it out (hopefully soon). I have certainly seen many other cases of new light launches (from various makers) where there have been flickering issues on Li-ion. Typically tends to be due to some specific circuit component not being quite up to spec - can take a bit of time to isolate, but once they do, it is usually resolved for good by changing the component. I'll let you know more when I hear more.

    Spotted only one error: "Again though, you are best to run the light on NiMH of L91 lithiums to see the best performance here." ...Did you mean "or"...or is this a new hybrid batt? Lol...
    Thanks, fixed that one. I'm sure there are a lot more ... it's a long review to proof-read.

    Quote Originally Posted by Mr Floppy View Post
    I found that the H51w was very fussy (i.e hard to get the highest mode) with a lot of NiMH AA batteries other than Eneloops.
    Interesting. Unfortunately, I've stuck with Eneloops-only NiMH for years now. I found the old high-capacity/high-self-discharge NiMH didn't hold up well to repeated use, and Eneloops have been rock solid performers.

    Quote Originally Posted by StandardBattery View Post
    Nice Review, I like the runtime tests. I'm a little sad to see that this light is not that well suited to the Lithium cells when used on Hi. The SC51 is much better for EDC with Lithium primary in my opinion even if it gives up some brightness.
    Well, to be fair, I've only done the highest two modes so far on L91. Let me try the Hi2B level and see how it does - that's when alkaline performance really started to pull away from the crowd. I'lll do it tomorrow and update the graph. Also, keep in mind as well that my relative output scale for the lightbox is not linear (i.e., the Hi1 and Hi2A are quite a bit brighter than the lower levels - my relative scale is not in estimated lumens).

    Looks like there are some typos from cut and past in the legend for the Medium level graphs as the modes are still listed as HiA and HiB. I think I saw some other typos in the legeneds, but I forget now.
    Thanks, I see what you mean - some of the "Hi2B" should actually be labelled M1. I'll fix the legends tomorrow, when I'm back in front of my main computer.
    Last edited by selfbuilt; 01-28-2013 at 09:03 PM.
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  12. #12

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Read, savoured and reread.

    Roger Ebert was the first film critic to win the Pulitzer Prize for Criticism. If there were one for flashlight reviews, I can think of no worthier candidate for it than Selfbuilt.

  13. #13

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Thanks for a timely and excellent review. I can't wait to get mine and maybe I should order another as I think I am really going to like this light and as good as it seems it might be in short supply for some time to come.


  14. #14
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    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Great review! Certainly one of the most anticipated reviews - of a light I already own

    I was one of the people doing my own tests on lithium primaries - comparing it with a few Eagletac lights. With that, the Zebralight came in relatively lower, but it's very plausible that the D25A Ti CLickies are simply brighter on lithiums than their NiMH rating, so I'm glad you were able to address these concerns.

    Thanks again for your time and effort in these reviews. I expressed my gratitude by hitting the donate button on your website for a small amount. I hope more people join in with that ^^

  15. #15
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    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Super review. Thanks again.

  16. #16

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Man! Awesome review, as usual. Thanks for spending all the time on it.

    There's been a lot of people waiting for this review - I am glad the lumen arguments can finally be laid to rest.

    Zebralight, and obviously selfbuilt too, have outdone themselves yet again!!!

  17. #17

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Thanks for a great review - much appreciated!
    I think many of us have been waiting to see this one.

  18. #18
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    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    I notice the sc52 doesn't come with a headband... does the sc52 fit inthe sc50/sc51 headband?
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  19. #19

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Quote Originally Posted by Swede74 View Post
    Read, savoured and reread. Roger Ebert was the first film critic to win the Pulitzer Prize for Criticism. If there were one for flashlight reviews, I can think of no worthier candidate for it than Selfbuilt.
    Thanks!

    Quote Originally Posted by TweakMDS View Post
    I was one of the people doing my own tests on lithium primaries - comparing it with a few Eagletac lights. With that, the Zebralight came in relatively lower, but it's very plausible that the D25A Ti CLickies are simply brighter on lithiums than their NiMH rating, so I'm glad you were able to address these concerns.
    Interesting. It's a shame Eagletac never sent me the D25A to review (I gathered at the time that they had difficulty keeping it in stock, which is why it wasn't sent out with the other models). The D25Cs that I have are certainly very highly driven, so it wouldn't surprise me that the D25A was as well. But unfortunately I don't have any data to compare.

    Thanks again for your time and effort in these reviews. I expressed my gratitude by hitting the donate button on your website for a small amount. I hope more people join in with that ^^
    Thanks, always appreciated as well!

    Quote Originally Posted by LEDburn View Post
    There's been a lot of people waiting for this review - I am glad the lumen arguments can finally be laid to rest.
    Well, I wouldn't say that exactly. Despite how it may sound above, I'm not trying to shut down any discussion of relative or absolute lumen level estimates. I think it's important to critically evaluate ALL claims of purported "lumen" values, to see if they hold up to scrutiny. My commentary above is just to add to the existing literature on my own method, so people can better understand my estimates (and the effort I put into making them the best I could).

    Truthfully, I resisted coming up with an estimated lumen scale for the longest time. I preferred (and still prefer) that people look at the full relative output/runtime data to get a better feel for how a light performs over time. But once a lot of people started posting their own "lumen" values here (some carefully considered, others not so much so), I realized I had to make an effort to provide a comparable scale. The point is that I did the best I could at the time to come up with an appropriate conversion (just like I've done more recently for high-output throwers that don't fit in my lightbox).

    Of course, even if you had the most accurate lumen estimates, I find the arbitrariness of two simple ANSI FL-1 measures frustrating. It can easily be misleading as to a light's true performance, unless you look at all the variables in-between. That's why the output/runtime graphs remain the staple of my reviews.

    Quote Originally Posted by hazna View Post
    I notice the sc52 doesn't come with a headband... does the sc52 fit inthe sc50/sc51 headband?
    Good question. There was no headband included on my SC50 or SC51, so I can't say for certain. There was of course the one that came with my H31 (i.e., the contemporary 1xCR123A headlamp version of that series), but I don't know if they made different size attachments for the CR123A vs AA lights. I would guess that they used the same attachment, as the head and tailcap pieces weren't that different in diameter. I just tried that one on my SC52, and it would be really hard to get over the head - but you could do it easily enough from the tailcap, if you removed the pocket clip first.
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  20. #20
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    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Nice one Selfbuilt! Ordered one before I even finished reading the review. I think we could call this THE most anticipated light review so far this year.

  21. #21
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    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Does this light get hot on H2B? I am wondering if the body gets hot enough to transfer waste heat to the cell, say if you used alkaline in a cold environment, to maintain flat regulation. Maybe if you intentionally insulated the light.
    But damn good regulation on M1. Kind of funny that the improved efficiency is making alkalines viable, well to the general populous not CPFers, of course.

  22. #22

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    looks like this review has finally won me over, i will purchase one soon
    fenix tk41..fenix tk35..nitecore ea4...olight s10 baton...xtar meteor...sipik 68...eagletac d25lc2...eagletac d25a...eagletac d25c ti 2013... a modded tn31..skyray king...nitecore dx.. sunwayman v11r.. + loads of other lights

  23. #23
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    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    I think I need one of these, dangit. I only have headlamp style Zebras so far, and this looks like the time to cross over to the flashlight form factor.

    I'm confused by the 14500 graphs. If I'm reading things correctly, the only reason to put a 14500 in one of these is for the first 30 seconds. After that, in every case, the eneloop outperforms Li-ion.. is that correct -- same output and longer runtimes on the eneloop? Not that I'm bashing that first 30 seconds. That's a lot of light.

  24. #24

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Quote Originally Posted by StandardBattery View Post
    Nice Review, I like the runtime tests. I'm a little sad to see that this light is not that well suited to the Lithium cells when used on Hi. The SC51 is much better for EDC with Lithium primary in my opinion even if it gives up some brightness.
    I've just updated the L91 runtime graph (1xAA) in the review with the H2B results:



    The L91 runtime on Hi2B is quite impressive - nearly twice the runtime as Eneloop at this output level, and about 3.5 times the runtime of standard alkaline. I'm surprised that it can outperform the SC51 by such a wide margin. It also demolishes the Nitecore MT1A at this level.

    I agree you are probably best sticking with NiMH if you plan to run on H1 ... but the L91s seem like an excellent option for H2A on down.

    Quote Originally Posted by MichaelW View Post
    Does this light get hot on H2B? I am wondering if the body gets hot enough to transfer waste heat to the cell, say if you used alkaline in a cold environment, to maintain flat regulation. Maybe if you intentionally insulated the light.
    But damn good regulation on M1. Kind of funny that the improved efficiency is making alkalines viable, well to the general populous not CPFers, of course.
    All my tests are done under a cooling fan, and it's definitely possible that alkaline may not have fared as well on H2B without it. Of course, most people don't run lights at this level for an hour continuously, so I think you could expect flat regulation at this level (on down) on alkaline in normal usage.

    I agree, it is rather ironic to see a modern light perform so well on the rather archaic alkaline cell. I would certainly never want to store one in there, given their propensity for leaking.

    Quote Originally Posted by pepekraft View Post
    I'm confused by the 14500 graphs. If I'm reading things correctly, the only reason to put a 14500 in one of these is for the first 30 seconds. After that, in every case, the eneloop outperforms Li-ion.. is that correct -- same output and longer runtimes on the eneloop? Not that I'm bashing that first 30 seconds. That's a lot of light.
    You are reading everything correctly - and the result is actually not that surprising.

    The two typical advantages of Li-ions over standard cells (in multi-power lights) is the ability to drive the emitter harder (i.e., the higher-voltage Li-ion can handle the higher current drain), and the improved ability to maintain flat regulation (i.e., Li-ions can more easily supply power fully regulated). In this case, the SC52 does a remarkable job keeping flat regulation on most cells (at all levels below Hi1), so that advantage is negated somewhat. The SC52 does run brighter on max Hi1 on 14500 - but due to the small heatsinking mass, the circuit won't keep it up for long (i.e., timed step-down after 1 min). So practically, you don't get to benefit much from these two typical 14500 features.

    The other question is battery capacity and relative circuit efficiency for different voltage sources. In the capacity sense, the actual work capacity of 14500 is not all that different from NiMH. In simple terms, you can think of this as the work done for the current to flow through a given voltage differential (i.e., the definition of a watt). If you multiply typical amperage capacity (in mAh) by nominal voltage (in V), you basically get work capacity (or Watt-hours, Wh) for a cell. The typical 14500 thus only has a small advantage over the typical NiMH for actual work capacity (how much exactly depends on how much you trust the rated mAh capacities).

    In an ideal situation, I would expect my 14500s to only have a small runtime advantage over Eneloop NiMH for a given output level. That said, there are also always potential differences in the relative circuit efficiencies of different voltage sources, which may skew things a bit one way or the other (i.e., depending which voltage source the light is optimized for). In the case of the SC52, standard batteries seem to have a greater edge - which gets back to why I consider the NiMH/Alkaline/L91 peformance to be outstanding on the SC52, and the 14500 performance only very good.
    Last edited by selfbuilt; 01-29-2013 at 02:29 PM.
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  25. #25

    Default Re

    I'm confused about the data in the high eneloop chart.

    If I'm reading it correctly I'm better off using the brighter of the two sub high modes, it will give me a higher output, with a flatter regulation, and a longer runtime?!

    Look like the lower level is unregulated and drops quickly. I must be reading the chart wrong.

    Thanks for the great review.
    73's Bill

    Sent from my Galaxy Nexus using Tapatalk 2

  26. #26

    Default

    Duh,

    Nevermind , just ignore the new guy. Apparently he's (me) color blind and can't read a simple chart. Lol. Nothing to see here move along.

    Bill

    Sent from my Galaxy Nexus using Tapatalk 2

  27. #27
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    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Great Review SB .

    Automatic stepping down when battery (AA and 14500) capacity is low

    Your run time graphs show any indicator to having this feature ?

  28. #28

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    This is a long post …. my apologies in advance.

    Quote Originally Posted by LEDburn View Post
    ....There's been a lot of people waiting for this review - I am glad the lumen arguments can finally be laid to rest....
    Quote Originally Posted by selfbuilt View Post
    ....Well, I wouldn't say that exactly. Despite how it may sound above, I'm not trying to shut down any discussion of relative or absolute lumen level estimates. I think it's important to critically evaluate ALL claims of purported "lumen" values, to see if they hold up to scrutiny....
    I agree w/ Selfbuilt and I’m quite certain that I am the one that started this whole liberal lumen scale thing with ZL and Selfbuilt. There has been only one other CPF member that has publicly back me, and while I don’t always agree with his political correctness in voicing opinions, I sometimes really wonder if it is only the three of us (Selfbuilt included) that truly understand the issues here. Selfbuilt is absolutely a stand-up guy, and sounds to be completely open to this discussion, and without taking any personal offense, for which I truly appreciate. I think we both understand each other. I am sorry that so many others do not get the point…. and/or of course, simply do not care.

    Quote Originally Posted by maxrep12 View Post
    Reppans,

    ....it appears like you have identified some lights whose manufacturers may have understated the lumen output.....

    .... These types of mistakes are made, both over and under ratings, and the responsibility for these errors rest squarely upon the manufacturer. The onus of correcting their ratings does not fall to Zebra or Selfbuilt.....

    ......We use ANSI measurements here. There are no Zebra lumens, Fenix Lumens, or collaborations between Selfbuilt and Zebralight. This past month seems to have brought out some unfortunate comments from some decidedly adversarial posters, calling both Selfbuilts and Zebralights integrity into question.....
    First off, there are no official "ANSI " lumens here... please read in detail both Selfbuilt's comments here, and his methodology discussion on his website. He is making an estimate based on a sample of manufacturers (best fit line), and if that sample is skewed, so is his scale. I am doing the same and I know my scale is skewed on the conservative side.

    I will admit to being the loudest voice on ZLs spec sheet overstatements and I do question the integrity of the company, partially due to the lumen exaggerations, but also for pulling things like tripling the 0.34 moonlight runtimes (vs a QAAX) by actually delivering only 1/3 of the spec'd lumens. Similar with the 2.7 L1 mode which also matches (sorry, "is supposed to match") the QAAX, and I have highlighted this in my earliest reviews of the SC52. These modes happen to be personal favorites of mine, but they are also important indicators of a flashlight's driver efficiency. Is this an honest mistake, grossly poor estimation, or deliberate misrepresentation? Imagine if Ferarri claimed one of its vehicles got 50 MPG.

    I don't have any issues with Selfbuilt's integrity and in fact am even more impressed by his willingness to discuss this issue openly.

    While I have more than voiced my opinion about Selfbuilt's liberal lumen calibration, I have also repeatedly said that his data is consistent and relative, and I frequently use his numbers as the basis from which to recalibrate the conservative manufacturers "up" for apples-to-apples comparisons in my posts. The big problem I have with liberal interpretations, especially from someone as respected as Selfbuilt, is that people automatically take it as a de facto ANSI certification. I personally believe, in the longer run, it will reward manufacturer bad behavior and eventually lead to less transparency for all us flashaholics. Having said all that, and I’ve repeatedly said this too, if I were in Selfbuilt’s shoes, I would do the same exact thing. Selfbuit has modestly stated here…..

    Quote Originally Posted by selfbuilt View Post
    ...Thanks. Yes, at the end of the day, I'll I can say is my relative scale is consistent over time. Even if it does seem slightly inflated, not sure there's much point in trying to come up with a new calibration - it would likely just create confusion between the "new" numbers and the "old". The consistency and backward-compatibility is more valuable in my mind than the absolute correlation.
    …. that it doesn’t make sense to recalibrate for practical reasons. However, I personally feel there is NO WAY HE CAN RECALIBATE, if only for POLITICAL reasons. Imagine if Selfbuilt were to adopt a more conservative lumen scale and then start reporting that ZL, and a few other liberal manufacturers, are not meeting their specifications. I suspect that Selfbuilt’s reviews will diminish in quantity as his supply of flashlights dry up. A man in his position, just like the automobile journalists, must walk a politically fine line with the manufacturers. The only resolution to this, in my mind, is to free Selfbuilt up, by turning him into a “Consumer Reports” of sorts, and have CPF members fund his flashlight purchases. If there’s any interest in this, I will happily offer to fund 10% of the pot, when it hits USD 2,000. Selfbuilt, I hope you do not take any offense to my suppositions here, once again, if I were you, I wouldn’t do a single thing differently.

    Now back the original question of whether ZL is overstating, and Selfbuilt’s scale is too liberal. I attach a couple of Selfbuilt’s recent Output/Runtime graphs for the 3V, 1xCR123 and 2xAA classes. I took the liberty of including manufacture max lumen specs as best as I could determine, and attempted to superimpose the SC52/L91 graph onto CR123 graph… I hope I’ve been reasonable fair and accurate with the data, please correct me where I am wrong. Here are the saiient points based on Selfbuilt’s review population above:

    1) 280 lumens appear to be the highest manufacturer specification (using a non Li-ion battery), and most are significantly lower than that, in the 3V class. The SC52 is spec’d right at that high water mark and with a 1.5V.
    2) Despite claiming THE highest lumen spec, the SC52 appears to be the bottom dweller on both charts, and probably, the furthest away from it's claimed spec. (assuming the others are remotely correct)
    3) Looking at Selfbuilt’s CR123 and 2xAA max lumen tables above, it appears that every light, save ZL and Jetbeam, have been “underrated” by their manufacturers.
    4) So, perhaps it is not so much that I've found the few manufacturers that understate their lights, rather, it appears that the current bar is set low enough to accommodate the lowest common denominators.

    When we are talking about really statistics and the use of “best fit lines” I strongly believe in bell curves, and for every light that has been understated by its manufacturer, there should be an equal number of lights that have been overstated by its manufacturer. So, where are all these overstated lights?

    Selfbuilt, apologies for referring to you in the third person, I feel I am still trying to explain my position to others. In the end, I suspect you may be one of the only people that understands, or cares, what I am talking about. Please do not take any of this personally, I hope it is merely construed as constructive criticism..... you're the best.




    Last edited by reppans; 01-29-2013 at 11:29 PM.

  29. #29

    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    Great review, Selfbuilt! This petite ZL is bound to be a real killer...

    Cheers

  30. #30
    Flashaholic* kosPap's Avatar
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    Default Re: Zebralight SC52 (XM-L, 1xAA, 1x14500) Review: RUNTIMES, BEAMSHOTS, VIDEO and more

    putting it up against the 2AA lights. what a bold thing to do!

    Since the light is 14500 compatible, it would be interesting to see how it does with the 14505 3V batteries

    then you can make a graph with the various battery chemistries on high mode.

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