Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

[selfbuilt]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

I've updated the main thread with results from my 4GREER 3100mAh battery (based on the Panasonic NCR18650A cell):

Basically, you get the exact same runtime profile as my Redilast 2900mAh cells on Max - just with an extra dozen or so minutes of runtime as the levels drops near the end.

I haven't bothered doing additional tests at the ~25% level, as it seems pretty clear there is no apparent circuit stabilization at the lower outputs (e.g., see HKJ's 40% and 6% voltage sweeps in his review).

As an aside, I appear to have confirmed my earlier supposition of excessive hum/whine being due to not making full contact with all three cells (i.e., hum disapppeared with further tightening of the tailcap). I have tried to measure the current draw on a single IMR-18650 cells at the lower outputs, and get extreme levels of whine/buzz at even the medium levels.

At around half max output, I measured current draw on single IMR-18650 to be just over 2.8A (EDIT: note that this reading is not accurate for a specific output, as the PWM and resistance in the DMM results in lower output and current when everything is connected). The whine was so severe at this level, I could feel the vibration through the handles of my multimeter leads. oo: At about a quarter max output, I measured 1.1A, and still had quite noticeable hum - but greatly attenuated (EDIT: again, these current readings are being affected by the resistance in the DMM).

As a result, I suspect my earlier speculation that an IMR26650 cell could work well in the light is unlikely. I don't have one to test, but you are likely to experience considerable whine if you try. Recommend you stick with 3x 18650 sources, as the manufacturer intended. :wave:

 

[candle lamp]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

Very good job. Thanks for your effort. Selfbuilt!

 

[mr.lumen]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

how can they claim

2800 AnSi Lumen ​

when tests done by our reviewers show so much less. I thought the Ansi rating was a standard of otf not emitter lumens...am i wrong? and i guess we wont see the updated version till the end of feb :-/
230 euros for the prototype model... a bit steep i wonder how much the updated version will be!?


http://xtarlight.de/index.php?cat=c10_comming-soon-comming-soon.html

 

[jake25]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

Pretty sure that's just a dealer try to make a big buck off the light. It's selling for $150 USD in the MP

 

[mr.lumen]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

ok cool i thougth it was xtars site but hopefully its not!

 

[Helmut.G]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

Although it is hard to select the <200 lumen output levels, I also measured the current at the lowest level I could obtain (which was ~30 estimated lumens). At this level, I got 4.8mA. Although difficult to give an exact runtime estimate, that would be expected to roughly translate into over 1600 hours (or over two months), for 3x 2600mAh cells. This is greater than the 330 hour estimate provided by Xtar.

These numbers are wrong.

30 lumens at 4.8mA at 4.2V would result in luminous efficacy of 30 lumens per 0.02016 Watt or 1488 lumens per Watt. And these aren't LED lumens but OTF including driver losses and optical losses.

That is way more than theoretically physically possible when all energy would be converted to light, and about ten times more than possible with an XM-L LED (including optical and electronic losses) at optimal current.
Since this light uses PWM (and thus likely a much higher current) it's even more off.

 

[selfbuilt]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

These numbers are wrong.

I've managed to lock on to an even lower low mode, which my lightbox estimates as below 20 lumens. Here is a shot of the DMM (on appropriate uAmA port), with a single fully-charged 18650 at this level.

As you can see, I am getting 2.8mA at this really low level.

And here are shots comparing the output at this level to my Novatac 120P on its 30 lumen setting (Novatac 120P on the left, S1 on the right - various exposures in low light conditions).

FYI, my lightbox and ceiling-bounce both agree the Novatac 30 lumen mode is brighter than the S1 at this level (which I estimate to be <20 lumens). So, I am getting ~15-20 lumens output on 2.8mA battery tailcap current, and ~30 lumens at 4.8mA (which is comparable), on a single 4.2V battery.

30 lumens at 4.8mA at 4.2V would result in luminous efficacy of 30 lumens per 0.02016 Watt or 1488 lumens per Watt. And these aren't LED lumens but OTF including driver losses and optical losses.

This is not my specialty, but I know that normally you can't infer luminous efficacy from tailcap current draws (i.e., due to the circuit, you typically need to actually measure current and voltage directly at the emitter). If you are looking at a direct-drive or a linear regulator light (which I believe this is), then I suppose tailcap current should be pretty comparable.

But where does the fact that there are 3 emitters involved factor in to the math? I have no idea how the emitters are wired together, but it seems to me that has to be taken into consideration somehow (i.e. this isn't the same as single emitter setup, as you are looking at the combined output of 3 emitters). :thinking:

EDIT: Actually, turns out the problem is that the output is lot lower when the DMM is in the path during the current readings. The PWM and extra resistance in the DMM results in lower current and output (scroll down for a discussion ...)

 

[Helmut.G]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

But where does the fact that there are 3 emitters involved factor in to the math? I have no idea how the emitters are wired together, but it seems to me that has to be taken into consideration somehow (i.e. this isn't the same as single emitter setup, as you are looking at the combined output of 3 emitters). :thinking:

I thought about that before posting, but in my opinion it doesn't make a difference.
I'll use some made up numbers for an example:

I you have an LED that can put out 5 lumens with a luminous efficacy of 150 lumens per watt (peak efficiency) or 100 lumens at 100 lm/W or 300 lumens at 60 lm/W then you can get 300 lumens out of one LED using 5 Watts of power or you can get 300 lumens from 3 LEDs using 3 Watts.
You need less power here using more LEDs because you use a current that causes the LEDs to be more efficient.

But when you go to the efficacy peak of the LEDs (5 lumens in my example) you can not do this again. You can have three LEDs put out 5 lumens each at maximum efficacy but if you lower the current to have less output from each individual emitter in order to achieve a combined output of 5 lm you will need more power.

The maximum efficacy doesn't increase when you use more LEDs.

Again, all numbers are not real numbers.

This is not my specialty, but I know that normally you can't infer luminous efficacy from tailcap current draws (i.e., due to the circuit, you typically need to actually measure current and voltage directly at the emitter). If you are looking at a direct-drive or a linear regulator light (which I believe this is), then I suppose tailcap current should be pretty comparable.

It's true that you can't calculate the actual efficacy from such measurements because you don't know the losses, so the actual efficacy of the LED is going to be higher than the calculation's result.
The calculated number is a lower limit of the actual value.

But since the result I'm getting is already a magnitude beyond possible (unless I made a major mistake), it's safe to say that something is wrong with those numbers even though only a lower limit is known.
measuring directly at the emitter would only make the resulting lm/w-figure even bigger.



I think maybe your meter is getting confused by the PWM.
Because if your lumen estimate is about right the current measurement has to be wrong, and you know selfbuilt doesn't estimate 30 when it's actually only 3 lumens (even without your comparison pics)


If somebody finds a mistake in my calculations please tell!

 

[selfbuilt]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

I'm sympathetic to your calculation result - I don't see an obviously flaw. And it's true I don't see how the 3 emitters changes things (it should all be proportionate). But logically, we are left with three possible explanations:

1. There's a flaw in the math (due to an incorrect assumption neither of us can recognize, but again this isn't my specialty) - or, as you put it:

If somebody finds a mistake in my calculations please tell!

2. My output readings are way off by an order of magnitude, but as you say:

Because if your lumen estimate is about right the current measurement has to be wrong, and you know selfbuilt doesn't estimate 30 when it's actually only 3 lumens (even without your comparison pics).

3. The DMM is not accurately reporting the current draw from the battery:

I think maybe your meter is getting confused by the PWM.

I'm obviously confident the problem is not with #2 - and personally, I'm hoping the problem is with #1. Otherwise, this would call into question the accuracy of current readings at really low outputs on PWM-based lights. Not a pleasant thought ...

EDIT: Actually, turns out that both #2 and #3 part of it - the PWM and extra resistance in the DMM results in lower current draws, reducing brightness while the current measures are being taken (scroll down for a discussion ...)

 

[HKJ]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

As Helmut G. writes, something is wrong, the absolutely maximum power than can go into the light is 2.8mA*4.2V -> 0.016 W.
Try measuring the lumen with the meter connected, it will be considerable lower than without the meter.

One of the problems is that the light uses pwm, i.e. even at the lowest brightness it is drawing nearly full current (That is 7 ampere), but only in very short spikes. With the meter adding maybe 1 ohm resistance this is not possible and will reduce the brightness and current.

To measure current in this light you need some good equipment and knowledge about how to use it, even 0.1 ohm resistance (Typical for many meters on 10A range) would be to much (Check the voltage sweep char in my review and see how much a 0.7 volt drop will change current and brightness).

 

[selfbuilt]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

Try measuring the lumen with the meter connected, it will be considerable lower than without the meter.
One of the problems is that the light uses pwm, i.e. even at the lowest brightness it is drawing nearly full current (That is 7 ampere), but only in very short spikes. With the meter adding maybe 1 ohm resistance this is not possible and will reduce the brightness and current.

Interesting thought about the PWM. And quite right about resistance effect - I should have checked the effect on output concurrently (i.e. I have seen times before where the resistance of the leads/port has reduced output).

Just took a look, and the output is indeed greatly reduced when the leads and DMM are in place, as you expected. I'll remove the current reads from the lower output readings in the review, since they clearly don't correlate to output levels with the DMM in the circuit.

 

[Helmut.G]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

Ah, I hadn't thought about the bad regulation of this light.

That probably explains the 330 hours runtime spec too, as I wouldn't believe that for a regulated light @30 lumens, my guts tell me its too long.
But the light's brightness decreases during the run and so does the current draw and 300 hours can be achieved easily.

 

[selfbuilt]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

I've just heard back from Xtar - here is the current list of revisions planned for the next iteration of this light:

• One can select from 1%-100% of output.
• Ramping time will increase from 7 sec to 15 sec, and will pause at 70%, 50%, 25% and 1%.
• Color temperature will drop from 7000k+ to ~5000K-6000k.
• Will use the correct SOS signal (previously was a SO signal)
• Control ring will not turn 360° any more, but only to those modes where there is a function for it.
• Will use an AR lens.

Personally, I don't really see the need for the 25% and 70% (75%?) pauses in the ramp . But the rest are all welcome revisions. :wave:

 

[candle lamp]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

I've just heard back from Xtar - here is the current list of revisions planned for the next iteration of this light:

• One can select from 1%-100% of output.
• Ramping time will increase from 7 sec to 15 sec, and will pause at 70%, 50%, 25% and 1%.
• Color temperature will drop from 7000k+ to ~5000K-6000k.
• Will use the correct SOS signal (previously was a SO signal)
• Control ring will not turn 360° any more, but only to those modes where there is a function for it.
• Will use an AR lens.

Personally, I don't really see the need for the 25% and 70% (75%?) pauses in the ramp . But the rest are all welcome revisions. :wave:

I agree with you. The short pause at 1% & 100% is enough.

It's fine Xtar is gathering feedback from the prospective customers & reviewers.
But I'd like to ask Xtar to revise S1 to be worked on flat-top 18650s(or unprotected cells) as well.
In this case, Xtar may need to add the low battery voltage protection function and it can drive up the overall cost of the light.
On the contrary to this, the customers can save the purchase cost of the protected cells.

I think Xtar just make customers to use button-top protected 18650 batteries in my view. :shakehead

 

[HKJ]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

The S1 (Like many single LiIon lights) does work fairly well on Panasonic 2900/3100 unprotected batteries. The only restriction is that the user must turn off the light when brightness has dropped or the battery is damaged. This can be seen from my voltage sweep curves where the current draw is nearly zero before the battery voltage is down to 2.5 volt (The safe low limit for Panasonic 2900/3100).

 

[candle lamp]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

That's a good information and thanks. HKJ!

The light doesn't work on flat-top 18650s including Panasonic unprotected cells due to the short battery length in the battery tube.
So user needs three small magnets or metals. But I think it's not a good method in real life.

 

[BLUE LED]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

It looks like I will have to buy the new Eagletac 18650 button top 3100mAh cells. I understand it would be better regulated using Redilast 2600mAh cells.

 

[int32]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

Hello, I'm newbie on this forum and I'm interested in this Xtar S1 light.
I'm looking for high power light. When I'm look on this graph I can make a conclusion that brightness of light falling down with time.
If so it's not good cause I want light with constant light output power.

So please make additional explanation: constant power or falling down?

 

[selfbuilt]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

So please make additional explanation: constant power or falling down?

:welcome:

The S1 is trying to maintain a stable output, but the power draw is more than 3x cells can handle in a fully regulated way. If the cells were able to provide more current at full voltage, you would see a much flatter discharge curve.

While most prefer perfectly flat stabilization, the drop-off shown here is actually pretty gradual in practice. For example, on the 3100mAh cell test, it took over 20 mins before the output dropped down ~10%. This is so slow that you will not be able to see the difference in real life.

 

[Ualnosaj]

Re: Xtar S1 (3xXM-L, 3x18650) "Thrower" Review: RUNTIMES, VIDEO, BEAMSHOTS and more!

Received a few of them today then jumped back on the forum... then realized from your video they are supposed to be battery-carrier-less! Wow.

Of course the next thing is realizing the flat AW don't fit so had to use the matched TrustFires

The lowest mode is like playing one of those arcade games where you try and stop the light at a certain point for tickets. I THINK I have the lowest mode but it took 4 tries, and it's difficult to really know if you're at the lowest. This ramping game is certainly frustrating...