Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOTS +

[pae77]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

Nice reviews.

Perhaps I missed it but one thing I didn't see mention of anywhere in the review is the maximum lumen output of the SC50w (and w+) on High 1 on 14500's, which is 169 lumen OTF according to ZL. H2, as was mentioned in the review, is 107 lumen on 14500s.

I find I use the 0.6 lumen lower low a lot on my SC50w+ (in fact I frequently leave it on that level all night since it has a 22 day runtime on the lower low level) so I would hope that ZL fixes the noticeable PWM issue on the low level for the production version of the SC51. I would rather have the 31 less lumens OTF of the SC50w+ on H1 (max with 14500s), than put up with noticeable PWM on the low modes of the SC51, but that's just my preference, of course.

It's nice that the hotspot is a little larger on the SC51 than it is on the SC50. Wish the transition to spill was a little smoother though (iows, wish the spill was a bit brighter) on both models, even if achieving that required making the large size of the spill area a little smaller.

 

[tandem]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

There's always the SC50/SC50+ series (while still available) .... the SC50w I tested here performed quite well for the class, and no visible PWM.

Couldn't go there now as I'm an AA runtime/output junkie. I've been very pleased with my Fenix LD10 R4 in that regard and up to this point had planned on picking up a few more but given your evaluation of the SC51 I'll have to consider that plan.

Given the following from your review:

However, the SC51 has a very noticeable 69 Hz on the lower Lo, and a more reasonable 437 Hz on the lower Med.

... I could probably live with that for biking as the lower low and medium are not of interest for riding, only the higher and lower highs are of any use, plus strobe (eliminating the H51 in my mind). I wonder if the light employs PWM in its strobe modes; hopefully not. I've found PWM from various lights quite reliably interferes with the operation of wireless (wheel motion sensor is not wired to computer) bike computers.

 

[leon2245]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

So I'm only aware of PWM from CPF, but never noticed it on l1, l4, l5, and a fenix & brinkmann LED- am I just not sensitive to it, or do these models not use this technology at all? They all appear to blink when I point them at a fan (ceiling fan test?), but so do the incans.

:thinking:

 

[yowzer]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

So I'm only aware of PWM from CPF, but never noticed it on l1, l4, l5, and a fenix & brinkmann LED- am I just not sensitive to it, or do these models not use this technology at all? They all appear to blink when I point them at a fan (ceiling fan test?), but so do the incans.

Not all lights have PWM. Using a light in rain or snow is a good test for it: If you see streaks coming down, it's because of low frequency PWM strobing.

Between the PWM and running my SC50w+ on a 14500, I think I'll pass on upgrading to the SC51w when it comes out. And hearing that the H51 has low-frequency PWM is disappointing... hope that gets fixed to SC50 frequency levels.

I don't think the SC51 and H51 have the exact same circuit; ZL's been saying the headlamp's not compatible with the voltage of 14500 cells, and they don't seem to blow up the SC51...

 

[selfbuilt]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

These are the claimed runtimes by ZL for H51. They look pretty close to SC51:
Light Output
High: H1 200 Lm (0.9 hrs) or H2 100 Lm (2.1 hrs)
Medium: M1 30 Lm (12 hrs) or M2 8 Lm (39 hrs)
Low: L1 2.5 Lm (3 days) or L2 0.2 Lm (19 days)

I don't think the SC51 and H51 have the exact same circuit; ZL's been saying the headlamp's not compatible with the voltage of 14500 cells, and they don't seem to blow up the SC51...

It's a good question - Zebralight hasn't informed of the specs for the SC51. They also didn't confirm 14500 compatibility - I just went ahead and tested that myself. It's possible the lights could use the same circuit - there is certainly precedent for that in their other SC/H models. Time will tell ...

Perhaps I missed it but one thing I didn't see mention of anywhere in the review is the maximum lumen output of the SC50w (and w+) on High 1 on 14500's, which is 169 lumen OTF according to ZL. H2, as was mentioned in the review, is 107 lumen on 14500s.

Sorry, accidentally dropped that when condensing the spec text. It's added back in.

I could probably live with that for biking as the lower low and medium are not of interest for riding, only the higher and lower highs are of any use, plus strobe (eliminating the H51 in my mind). I wonder if the light employs PWM in its strobe modes; hopefully not. I've found PWM from various lights quite reliably interferes with the operation of wireless (wheel motion sensor is not wired to computer) bike computers.

Interesting finding about wireless bike sensors, I've never heard of that one before.

For a full power strobe, there would be no additional cycle sequence within the constant output. In essence, you get very slow PWM - 2 cycles per second (strobe) instead of hundreds or thousands of cycles per second (PWM). If you had a light with a low output strobe, then I suppose it's possible that PWM could be used (although I would expect a low current would be far more likely).

So I'm only aware of PWM from CPF, but never noticed it on l1, l4, l5, and a fenix & brinkmann LED- am I just not sensitive to it, or do these models not use this technology at all? They all appear to blink when I point them at a fan (ceiling fan test?), but so do the incans.

Fenix doesn't use PWM for its low mode - all are current controlled. Frankly, PWM isn't really an issue if the freq is high enough. It is pretty much undetectable in kHz range, and typically only enters your perception threshold somewhere <1kHz. Under ~200 Hz or so is very noticeable for those who are sensitive to it. You will see it as a corner-of-your-eye "flicker" (or more accurately, latent "ghost" images during your eye saccades).

Most makers who use it keep the frequency high, but some circuit designs make that difficult (for technical reasons that I am not an expert on).

 

[LiteShow]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

Hi Selfbuilt,

Would you be able to measure the current draw at the tail cap of the SC51 in high mode using a nimh?

The current draw on my SC50 in high mode using a nimh is about 1.1 A - with a rated 122 lumens output. I am just curious how much current is needed for the SC51 to push 14500 brightness using only 1.2 volts.

 

[selfbuilt]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

Would you be able to measure the current draw at the tail cap of the SC51 in high mode using a nimh?

Ok, but first with the BIG caveat that I don't trust tailcap current draws on max output. Even on my DMM's 10A scale, I know from previous testing the actual output tends to drop somewhat when doing these, suggesting a resistance issue somewhere with the DMM. That being said, here are the initial readings that I get with a Sanyo Eneloop NiMH:

SC50w: 1.15A on max Hi (i.e. 107 Lm for the "w" version, 120 Lm for the cool white equivalent)
SC51: 2.15A on max Hi (i.e. 200 Lm?)
SC51: 1.05A on secondary Hi (i.e. 100 Lm?)

Lumen estimates for the SC51 are simply based on the H51 numbers - I have no reliable info yet. But these numbers do seem reasonable for those potential specs.

 

[tandem]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

Interesting finding about wireless bike sensors, I've never heard of that one before.

Within the night cycling community it's a known problem for a while now and it seems a great many wireless bike computers are affected. I suspect the magnet-induced signal from the wheel sensor is transmitting a fairly simple digital pulse; some more advanced units might include some basic encoding to avoid cross talk between nearby bikes. Typically what happens is when a light using PWM is within proximity (mounted on the handlebar) the computer either freezes or registers no motion regardless of current velocity. Simple EMI jamming!

I've not used an all-metal general purpose flashlight that employs PWM on my bike so I can't be sure that the EMI issue would remain present but would not be surprised.

For a full power strobe, there would be no additional cycle sequence within the constant output.

agreed

If you had a light with a low output strobe, then I suppose it's possible that PWM could be used (although I would expect a low current would be far more likely).

This may be more common in bike oriented lights which tend to use not a constant strobe at X frequency but issue instead a pattern of light bursts, higher and lower outputs. Perhaps some general purpose flashlights have a beacon-ish type mode which puts out this typically attention getting sort of pattern.

A major bike light producer, Planet Bike, has a pretty bright product out - the "Blaze 2W" - sadly it uses PWM on both its low and strobe outputs. Running the unit on max output does not, as you'd expect, employ PWM. Sadly, strobe seems to, and that's such a common use case that it makes the output mode unusable.

Fenix doesn't use PWM for its low mode - all are current controlled.

And they still get great runtimes in lights like the LD10 R4.

After discovering the PWM EMI problem with bike computers I've more or less avowed never to knowingly buy a bike light or flashlight (that could see duty on a bike) that uses PWM. In the case of the SC51 it at least has output levels that are not so afflicted and these are more likely the levels that would be actually used on a moving bike.

I could see an H51 or SC51 worn on my noggin... I'll have to try a test with a known offender attached to my helmet to see if the increased separation is enough to minimize EMI jamming.

 

[tandem]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

I don't think the SC51 and H51 have the exact same circuit; ZL's been saying the headlamp's not compatible with the voltage of 14500 cells, and they don't seem to blow up the SC51...

One notable difference is the lack of a strobe output in the H51's published specs unless I've missed that somewhere.

Oops, ignore the above, I confused the SC50 with the SC51, according to Selfbuilt's review the SC51 dropped strobe mode, and published specs on the H51 also indicate no strobe output. Hmnn, that's a negative for bikers for the H51/SC51. I use strobe output on the LD10 all the time during the day for riding in traffic. it'd have been nice to optionally enable it.

 

[RedForest UK]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

This was the review I've been waiting for. :thumbsup:

What impresses me most is the SC51's output on High2 mode, the Fenix LD10 R4 has been independently measured at over 170 lumens OTF on turbo. The SC51 on H1 shows possibly the 200 lumen claimed, but the H2 shows what appears to be roughly 150 lumens from a single eneloop for 90 minutes! Even more than advertised on the specs of the H51. :thinking:

 

[davidt1]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

One notable difference is the lack of a strobe output in the H51's published specs unless I've missed that somewhere.

Oops, ignore the above, I confused the SC50 with the SC51, according to Selfbuilt's review the SC51 dropped strobe mode, and published specs on the H51 also indicate no strobe output. Hmnn, that's a negative for bikers for the H51/SC51. I use strobe output on the LD10 all the time during the day for riding in traffic. it'd have been nice to optionally enable it.

It's unfortunate that Zebralight left out the emergency mode on the new lights. They jumped on the maximum brightness mentality that's popular at the moment. There are six modes. How many people need all six modes? My H501 has 3 modes plus an emergency mode. I am very happy with those modes. Five modes plus an emergency mode would make the light more versatile. But no they have to listen to the whining morons who don't like emergency modes.

 

[LiteShow]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

Ok, but first with the BIG caveat that I don't trust tailcap current draws on max output. Even on my DMM's 10A scale, I know from previous testing the actual output tends to drop somewhat when doing these, suggesting a resistance issue somewhere with the DMM. That being said, here are the initial readings that I get with a Sanyo Eneloop NiMH:

SC50w: 1.15A on max Hi (i.e. 107 Lm for the "w" version, 120 Lm for the cool white equivalent)
SC51: 2.15A on max Hi (i.e. 200 Lm?)
SC51: 1.05A on secondary Hi (i.e. 100 Lm?)

Lumen estimates for the SC51 are simply based on the H51 numbers - I have no reliable info yet. But these numbers do seem reasonable for those potential specs.

Thanks for the info Selfbuilt. That helps alot! Yes the internal resistance of the DMM may play a part, but at least we get some rough idea how much current is drawn.

That being said, this means that the SC51 on high is roughly pulling 1C on a 2000M mAh Eneloop. Is there a Max/Safe discharge rate for an AA LSD Nimh, and is it safe to run for long periods of time? I am assuming Nimh to be very tolerant so am not expecting the cell to leak or vent, but would that high of a discharge rate shorten the life of the cell? Maybe this question belongs in the Battery section?

 

[tandem]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

That being said, this means that the SC51 on high is roughly pulling 1C on a 2000M mAh Eneloop. Is there a Max/Safe discharge rate for an AA LSD Nimh, and is it safe to run for long periods of time?

No doubt this belongs in the battery subforum but in general for the crop of newer high performance single AA lights the situation is bright indeed...

Sanyo's information site suggests that even > 1C discharge rates will deliver good performance but it doesn't talk about cell longevity degradation. At 2$ a cell on sale for Eneloop/Duraloops, I simply don't care much if I get 300 cycles or 500 or even 100. Edit: Here at CPF Silverfox has a study where higher rate charge and discharges were performed to get a sense of cycle life.

 

[HKJ]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

For a full power strobe, there would be no additional cycle sequence within the constant output. In essence, you get very slow PWM - 2 cycles per second (strobe) instead of hundreds or thousands of cycles per second (PWM). If you had a light with a low output strobe, then I suppose it's possible that PWM could be used (although I would expect a low current would be far more likely).

Some light does not disable pwm at full power, but uses 98% or 99% pwm for full power (IFE1 uses 62%, but they also did everything to spoil a good idea and good construction).
No light that I have tested disables pwm for flashing modes, but they combines pwm with the flashing mode, sometimes lowering the pwm frequency.

 

[selfbuilt]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

It's unfortunate that Zebralight left out the emergency mode on the new lights. They jumped on the maximum brightness mentality that's popular at the moment. ... Five modes plus an emergency mode would make the light more versatile. But no they have to listen to the whining morons who don't like emergency modes.

Although I didn't get into it in the review, I personally like 2Hz signaling strobe on the older SC50 series.

I think the issue with all the modern ZL light is that a lot of people complained about the lack of a secondary Hi (i.e. they found primary Med too far away from primary Hi, especially on 14500/RCR). This is presumably why they partially removed it on the "+" modes (i.e. replaced with secondary Hi on 14500). I guess this is the progression of that thinking. :shrug:

To be honest, I do like the idea of the secondary Hi - it's probably secondary Med that I could most easily dispense with of all 6 modes. But that would clutter up the interface to have Strobe as secondary Med.

As a personal plea, I hope other makers abandon the ever-present "tacticool" high freq strobes on consumer lights. I'm not going to try and incapacitate someone with a 1xAA or 1xAAA light. A nice slow signalling strobe (1-2 Hz) is ideal for the regular user, methinks.

No doubt this belongs in the battery subforum but in general for the crop of newer high performance single AA lights the situation is bright indeed...

Yes, this is definitely more an area for those with expertise in the battery forum. Personally, I wouldn't worry about ~1-1.5C discharge rate.

Some light does not disable pwm at full power, but uses 98% or 99% pwm for full power (IFE1 uses 62%, but they also did everything to spoil a good idea and good construction).
No light that I have tested disables pwm for flashing modes, but they combines pwm with the flashing mode, sometimes lowering the pwm frequency.

Interesting, thanks HKJ. Most of my lights with PWM don't seem to have it at full power - at least, I'm not able to detect it with my setup. What is your experience as to how common it is to still see PWM (98-99%) on full power?

 

[HKJ]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

Interesting, thanks HKJ. Most of my lights with PWM don't seem to have it at full power - at least, I'm not able to detect it with my setup. What is your experience as to how common it is to still see PWM (98-99%) on full power?

I can not really put a percent on it, but it happens. Here are a few examples: C2H: Max is 91%, Mr.Lite 98% and the IFE1: 62%.
One reason to not reach 100% (i.e. no pwm) at full power is to save a few bytes in the program, I have not tried to program a microprocessor for a flashlight (But have done it for many other application) and do not really know if this is a valid reason (I would suspect not).
As you probably have seen I can easily catch a fast pwm (100+ kHz), and with the setup I am using I can show it or filter it out when showing flashing modes or brightness. Filtering it out can be a advantage when looking for the actual brightness.

 

[selfbuilt]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

I've gotten some updates from Zebralight on the issues identified for the SC51 in the review:

• The H51 and SC51 share the same circuit (a buck-boost, that has been heavily optimized since the original H50)
• My engineering sample had a lower PWM, but the final shipping version should be close to those found in the SC30/H31 (i.e. twice what I found on the SC51).
• ZL explains that they use lower freq PWM in the Low2 level for improved circuit efficiency. They claim to be able to filter out the visible PWM with the capacitor in the output stage, even though the PWM may still be detectable by oscilloscope.
• The positive contacts used in the SC51 are simply from a new batch, which presumably explains the heightened sensitivity to flat tops. Nothing is changed in terms of positive polarity detection.
• They purposefully toned down the 14500 performance to closer to the L91/NIMH for safety concerns on Li ions (protected or not).
• ZL confirmed that parasitic drain is lower on the AA-series lights, compared to their other offerings. They say they will try to implement this feature on the SC30/SC60/H31 lights in the future.
• One minor difference between the SC50 and SC51 that I didn't note - the threading is a bit thicker now - 1.25mm pitch. In addition to the same circuit, the SC51 and H51 also use the same thread, and tailcap.

:wave:

 

[hazna]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

If the circuit is the same as the h51 does this mean its not meant to run on 14500?

 

[tandem]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

the final shipping version should be close to those found in the SC30/H31 (i.e. twice what I found on the SC51

+1 for x2!

I'm so blown away by the output and runtimes of the SC51 (and I've been blown away by the LD10R4 in real use) that I think I'll overlook the lack of strobe and figure one or two of these in to my buying plans. I sure hope the LD10 R4 and now the SC51 introduction are road signs pointing on more optimizations to come from these and other manufacturers.

 

[selfbuilt]

Re: Zebralight SC51 (XP-G R4) & SC50w (XP-E Neutral) 1xAA Reviews: RUNTIMES, BEAMSHOT

If the circuit is the same as the h51 does this mean its not meant to run on 14500?

ZL also informed that they purposefully toned down the 14500 performance to closer to the L91/NIMH for safety concerns on Li ions (protected or not).

So that would tell me that 14500 are supported ... but I suppose they may still not be officially supporting them. :shrug: In any case, I don't see a problem - unless you need a magnetic spacer to make contact as mine did. I seriously do not recommend that, as those magnets are a real safety concern (i.e. they could potentially short the cell)