ZEBRALIGHT REVIEW – 2 Malfunctions in all 4 lights

Connor

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I have/had 7 ZebraLights over the last ~6 years, no problems except a minor UI glitch when programming the levels on a first run SC600Fd MkIV (works fine otherwise).

To be honest, if you guys are using cells like the NCR18650GA (non high discharge) at << 0°C shitty performance is to be expected. If the cell itself is at -10 to -15°C it will drop below the low voltage shut-off almost immediately when you turn it on on H1.
 

Fireclaw18

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To be honest, if you guys are using cells like the NCR18650GA (non high discharge) at << 0°C shitty performance is to be expected. If the cell itself is at -10 to -15°C it will drop below the low voltage shut-off almost immediately when you turn it on on H1.


I do not use crappy cells in my Zebralights. I mostly run them on Samsung 30Q and Sony VTC5A or VTC6 purchased from Mountain Electronics.

Or for the lights running 16340 or 14500 I typically used quality (for the time) Efest IMR cells purchased from Mountain Electronics or Illumn. For some of my earlier Zebralights I used Zebralight brand cells purchased direct from Zebralight's website together with the light.

... and yet I still had 10 defective lights out of 17 purchased.

Also in most cases the defects usually weren't visible right when the light came out of the box. Instead they tended to develop and grow over a the next week or two.
 
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Duster1671

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I have/had 7 ZebraLights over the last ~6 years, no problems except a minor UI glitch when programming the levels on a first run SC600Fd MkIV (works fine otherwise).

To be honest, if you guys are using cells like the NCR18650GA (non high discharge) at << 0°C shitty performance is to be expected. If the cell itself is at -10 to -15°C it will drop below the low voltage shut-off almost immediately when you turn it on on H1.

Like Fireclaw18, I'm not using GA cells, I'm using good quality VTC6s that should have no problem delivering enough current to run my SC600w HI on H1, even at the ~0C temps where it's malfunctioning.

There is something wrong with (some of) these lights, not the batteries.
 

Fireclaw18

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Just dug up my broken SC32w. Never dropped and barely used. Anodizing is completely blemish free.

Tried CR123 and various different fully-charge 16340 including Efest and Vapcell.

It's completely dead. Nothing happens when the button is pressed. One of these days I might get around to sending it back to Zebralight for repair.
 

WalkIntoTheLight

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Okay, trying to see if I can reproduce it with an almost-empty cell.

Drained a 30Q cell to 3.0v. Popped it in the SC600w MkIV HI. Turned on H1. Light goes to full output for a couple of seconds, then steps down to medium. Normal behavior.

I tried letting it run for awhile, to get the cell down close to the ~2.7v LVP cut-off. I got bored, so instead froze the light for 1 hour in the freezer.

From frozen, turning on H1 causes it to struggle a bit to maintain full brightness for a second or two, then goes to medium briefly, then low. Normal behavior.

After it warms up for a few minutes, it can now maintain medium again. But no sign of "shut off from H1".

Okay, now I'll start the long process of just letting it run down the battery until it shuts off. This will likely take many hours, as it happily sips juice when it eventually settles down at a very low output. Hopefully, after that, the cell will rebound just enough to let me turn it on to H1, then I'll see if the behavior is similar to the bug I've seen.

The behavior of the bug is a little weird. It doesn't actually shut off the driver. When it "turns off from H1", it really just cuts power to the LED. Clicking the button once again, actually shuts off the driver like you normally do when shutting off the light. You have to click again to turn the light back on. Or, you can double-click after it "turns off from H1", and it will turn on to H2. So the driver appears to think it's still turned on in H1, even though there's no light coming out.

I'm not sure if that's the expected behavior that happens when the LVP kicks in at around 2.7v. I guess I'll find out... eventually. If I can turn the light back on after LVP kicks in, that is.
 

Duster1671

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Zebralight CS mentioned that they've seen one or two lights with the "H1 shutoff" malfunction where the target temperature was not calibrated properly. In their words, "WAY above the 50C default target."

I'm not sure if that means the PID set point was set way too high or that the temperature sensor was not calibrated correctly. If the light is measuring its temperature accurately but the set point is too high, it would just run at full brightness for longer and get hotter than it should.

But if the temperature sensor was calibrated incorrectly and the light thinks it's much hotter than it actually is, that may actually explain the "H1 shutoff" behavior. If the light thinks the measured temperature is much higher than the set point, the fastest way to cool itself down would be to cut power to the LED entirely. The most aggressive form of ramp down.

That's also consistent with the observations that the driver is still running when the "H1 shutoff" occurs. The light hasn't turned off, it's just ramped down so aggressively that the LED is getting no power at all.

I'm not sure why this behavior would be inconsistent and seemingly sensitive to cooler ambient temperatures, though. If the temp sensor is reliable but simply miscalibrated, the light should shut off every time. Perhaps some of these lights have flaky temperature sensors?
 

WalkIntoTheLight

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Interesting about the temperature sensor. Although it works 100% in warm temperatures, maybe in cold temperatures it gets confused when going from freezing (when off) to suddenly hot when H1 is turned on. Other PID modes work fine (at least as far as I can tell), so it must be something to do with a dramatic change in internal temperature. No problems using H1 after the light warms up just a touch (a couple of seconds on is enough).

Anyway, I finally drained my battery. LVP works very well. After it drops down to medium (because the voltage drops too low), you get about an hour at that level. Then it goes to low for several hours. Finally, off. A single click will turn the light back on to high (though it struggles), about a second later to medium, a second after that to low, then a second later to off. Battery was 2.65v when I removed it, gradually rebounding to 2.70v an hour later. Note that the single-click to turn it on again means it's not the same behavior as the H1 temperature bug. I think this eliminates batteries as the cause.

Has anyone seen the H1 bug with default PID configuration? That is, they either never changed PID, or reset it back to default long ago.

When weather conditions allow me to reproduce the bug, I'll try resetting PID back to default. I currently have it set to -5C. It might just be a red herring, but messing with the PID config might be part of the issue. AFAIK, Zebralight never disclosed how to change PID, until they got enough people asking about it. So maybe it's something we shouldn't mess with.
 

xevious

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Kind of surprising to hear of anyone having an over 50% issue rate across a range of 10 ZL flashlights. I've never had an issue with the 3 I've owned.

I started out with an SC52w. I wasn't crazy about the tint and shift, but loved everything else about the light. Later I got the SC64c LE that revealed such perfection that I sold off my SC52w. Later, I wanted to at least get one of the "old school" headlamps, because the design is so unusual looking. Picked up a lightly used H51fw AA. This thing is so tiny. And it works great. I just wish there was more output on high. Very little deviation from H1 and H2 on a NiMH AA. Otherwise, flawless in all other respects.
 

SSANDERS

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I have/had 7 ZebraLights over the last ~6 years, no problems except a minor UI glitch when programming the levels on a first run SC600Fd MkIV (works fine otherwise).

To be honest, if you guys are using cells like the NCR18650GA (non high discharge) at << 0°C shitty performance is to be expected. If the cell itself is at -10 to -15°C it will drop below the low voltage shut-off almost immediately when you turn it on on H1.

I'm not an 18650 guru, but since when are Sanyo GAs not high discharge? (10A).
Is that not the cell that ZL still recommends, and generally considered one of the better 18650s?
 

Connor

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@ssanders

The NCR18650GA is the best high capacity cell but it quickly deteriorates at temperatures <0°C. If your battery will get cold (e.g. when you leave it in a car) you really have to use a cell like the Sony VTC6 or similar, those do much better in the cold.
 

WalkIntoTheLight

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Agreed about the GA not being a great cell for cold weather. Zebralight designs are done in Texas, so cold for them likely means having to put on a shirt. But, I don't believe that's the issue with the H1 bug that sometimes occurs in the cold.
 

Lou Minescence

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I am figuring the H1 shut off issue everyone refers to is the maximum lumen setting the light is capable of. Has anyone tried programing their lights to only be capable of the second highest lumen setting possible had better results with no shut off problems ?
Both my SC64w Hi and SC600w HI shut off at their highest lumen setting sometimes. I figure I'm going to try to keep the max setting at the second highest possible. I figure a few less lumens with no shutting off and trusting the light would be a good trade off. Any experience ? Thanks
 

Mr. LED

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That’s a workaround used by many to avoiding the shutoffs, just use H2 as your highest mode.
 

peter yetman

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Why not? Just accept the light isn't up to running at its highest setting and go with it. It's probably a nice light apart from that.
P
 

WalkIntoTheLight

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Yes, it only seem to shut off occasionally if you turn it on to the max setting, so you can use H2 no problem (then step-up to H1 if you need it). With mine, it happens only in cold weather. Since I wasn't out in weather much below -5C this winter, I haven't seen the issue in over a year. I also think a breeze (in winter) has something to do with it, but I know that sounds crazy. For example, I can't reproduce it in a freezer, nor in calm winter conditions below -20C. Go figure. Happens with my Zebras with the XHP35 HI emmitter. Haven't seen the issue with my XHP50 zebras. Probably different driver.

It's annoying, but very rare unless the weather conditions are just right. It's not an issue if you leave your light on; it's only a start-up thing. Still annoying, though.
 

toadgravy

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Sep 21, 2020
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Unfortunately my new h600d iv started dropping out of turbo to a very low level. I sent it back for a refund. Still love my sc62w. I have had issues with 2 out of 5 Zebras.
 

recDNA

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I lost my sc64 which I purchased in 2018. I was shocked to see no new flashlights in the sc60's line.

My sc64 has been my EDC for 3 years now. No problems with it.

Is Zebralight still in business and making prompt deliveries?

I don't see anything better than my sc64 with < 1 inch head. It's for pocket and I find sc600 series uncomfortable to carry.

I would have preferred something with a narrower beam but nothing new really.

Sent from my SM-N960U1 using Tapatalk
 

Derek Dean

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Yes, as as far as I can tell Zebralight is still in business. Even thought the SC64c LE was listed as Back ordered, I went ahead and ordered one anyway. That was 2 weeks ago. After about a week, I got the shipping notice and it arrived just a few days later, shiny and new and in perfect working order. It's a great little light. LOVE the new clip.

So, if you feel like taking a chance, go ahead and order another light on their website and see what happens.
 

recDNA

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May I ask when you last ordered and received a flashlight from them?

Sent from my SM-N960U1 using Tapatalk
 

Derek Dean

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recDNA. I ordered the SC64c LE from Zebralight on Friday Feb. 26th, 2021. I got the shipping notice on Thursday, March 4th, 2021, and received the light on Monday March 8th, 2021.

It's important to note that it was listed as "Back Ordered" at the time I ordered it, but I had read that other folks had also ordered their SC64c LE when it was listed as "Back Ordered", and that it had shipped after a week or so, so I took a chance, and by golly it payed off. It's a great little light : )
 
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