Review: XTAR S1 (3 x XM-L U2, magnetic ring selector, 30 - 2800 lumens ANSI)

Your challenge of 2100 is unnecessary and unwarranted.

He has contributed real data to this site, not just a bunch of "that torch sux" comments.

Agreed.

I think it's safe to assume he paid for it and wasn't given a free sample by Xtar.

I thought the SR92 battery pack contained 6x 18650 cells, this only uses 3 so it's hardly a fair comparison. I do agree however that the lack of regulation is not ideal and is a deal breaker for me, along with the PWM. Not that I need any more lights at the moment or in fact ever.. (I'm sure this won't stop me in the future though!)

A little known fact is that PWM actually uses current, (not only as it involves bursting the LED at a higher current and so doesn't take advantage of higher efficiency at lower current inputs) but each switch from on/off of the LED uses a tiny amount of electricity, this means that lower freq PWM is actually higher efficiency then high frequency, and is why zebralight originally used it in L2 mode of the H51 etc as it was more efficient to use low freq PWM than current control as the current to the LED would have been below optimal efficiency level. I'm not sure if this consideration comes into question when manufacturers are deciding what frequency to set PWM but it's an interesting fact.

I for one think it's one hell of a light. I even told Rick that last week on the phone. But I also can now say they won't be selling very many to US buyers for $175 shipped to the US. For that kind of money, I can buy a brand new Fenix TK70 for $164 shipped to my door.

Don't worry about 2100. He is a big bad boy, he can handle it.

So can I.Why did he mention single 18650 lights? In response to my question?

That's what is cannot understand. He was not as objective as selfbuilt?

Personally I have never liked selfbuit's reviews as I did not understand it fully but as I got to know more about lights, his reviews have made sense.

I brought in 1 x 18650 sincel-cell lights for comparison because those are just single-cell lights, ie 3.7-4.2V discharge range. This Xtar S1 is a 4.2V light, just that it is like 9AH in capacity with 3 cells in parallel. But then there are also 3 LEDs and 3 individual drivers. This is more of a technical/engineering topic rather than a semantics "how many cells the light's got".... My understanding is that it is not easy to boost a light of this nature to maintain a pretty flat output all the way till the cell is near 100% discharged (driver input voltage is below emitter's Vf). A cell could be at 3.0V under load and you still want to get 700 lumens from it. I am not a driver expert, maybe those into electronics can chime in.

Don't worry how2/xed8888/chicago X....i am not mad or anything, and anyway it's natural to suspect that i got a free light. The light was sent to me on promise that i don't reveal what i paid because that'd affect the on-sale price....but i certainly did not pay a budget light price. Still comfortably above 100 bucks. LOL!

Remember, i got the light and and shared measurements before I could see any reports at BLF and CPF (except the folks at shoudian), ie i dived in 100% blind. And such things are definitely not for fun and laughter, if you know what i mean. I have actually asked like 5 vendors for availability.

I am not sure if i understand the word direct drive correctly. With DD that it means the light is directly driven by the cell right? It could be direct hardwire, it could go through a driver's electronics but basically in DD mode the driver does not limit nothing. This is my understanding.

But if there is a resistor in there or a driver which limits the current, then it is not direct drive though it could be unregulated (seperate matter). This is because in the CPF reviews, the direct drive is mentioned multiple times. Maybe it's coz i have been doing playing with too many DRY 3 x XM-L, now that's DD. heh... (ok so the latest driver is still 90% PWM in Turbo). Perhaps i am wrong and the correct info is something that i can learn too.

Here (it's the same as place as the XTAR 18700 group buy) :

Look bros...it is funny that the word objectivity should even be mentioned. I thought real-world scenarios sharing is good. LOL!

Ok...I presented all the beamshots + measurements and that is objective data. But I need to be "subjective" as well because in the real world that is important too. It's the same in the Hifi/Photography/car mods arena. Specs and measurements tell you that part of the story only. As a professional photographer of many years (Chicago X too), we only know that too well. Same goes for car mods, which X dabbles in as well as for income. LOL! I am not saying that it's not important, numbers is the lifeline of engineers.

What is the diff of 20% out? It's 20%...nothing more to that. If you want throw, you'd need heck lots more. If you have lights that surpass 0.5-1 mil cd you probably can appreciate this more....else it'd always be in that XR-E/XM-L 50-60mm head diameter kind of performance and range and say that hey this XM-L thrower throws very well. I'm just trying to bring this sense of "scale" into the big picture....

PS. I have experience (in events) in which we've got several billions of candlepower comfortably from nearly 50 advertising search lights each of > 5kW (it was a mix), and it threw 10km, but barely only. Of course they were trying to light up the clouds (the wispy ones, cirrus). That's real world sharing for you.... and that's the truth of searchlights in the real world. LED Search & Rescue lights often advertise that they can do 700m, 1km. :)

The light is definitely not direct drive, it is more like a 7135 driver as can be seen on the voltage sweeps curves in my review.

I see, thanks! heh... i really ought to do more study into drivers. (electronics is not my forte)

Only saw your reply till now. heh... Actually in the first post, i already posted this : This is a review copy which I paid for it but the retail copy/packaging and pricing should be firmed up after Chinese New Year (23st Jan).

Note Review and Retail. I don't want to use Engineering set, which i have encountered many from Blackberry/Nokia/Samsung/etc as a telco worker....hehe

You are correct to say that. However that is OTF lumens output. When we look at the throw it's a different story. In terms of his measurement, it is 55k cd for the Xtar S1 and 45k cd for the SR92. That's a difference of 20%. (very small difference in reality only). Take Selfbuilt's output to be 380 units for his 55k cd measurement (think he measures after 3 mins), even if it drops to 300 units, it'd still be 43.4k cd, close to SR92. So probably both lights are quite near in candela. I am not sure if anybody would use this as a thrower or as a high output tool, that i leave it to the individual. I guess this is good for medium distances.

Another question from you : does the Xtar S1 lens have AR coating?

Ans : No. As reported earlier in the second post, the lens cuts 10% (so i am covering up anything and purposely leaving out any points, same for the PWM). 2 x UCL lenses are coming, and I will report back to see if they fit properly.

XTAR will be doing some changes to the driver for the retail version. One confirmed change is a short pause at lowest point so that it's easy to select.

PS to others. Maybe i have missed your question as many were asked, but i hope i managed to answer all major questions asked. PM me if you have something important to ask.

In addition to the things that various reviewers (on BLF and elsewhere) have pointed out as shortcomings, I've emailed xtar to ask for the following changes in a future version of the S1. The person I contacted said that these are more difficult changes to implement, so no guarantees. Do any of you think they'd be good additions? Maybe if more of us speak up, Xtar might be more willing to make the changes:

- Provide at least 2 steady modes: High and Low. We could use the Preset mode for “medium”. But I would still prefer 3 or 4 steady modes in addition to the Preset mode.
- Give us a choice of neutral white LEDs.
- Make the selector ring difficult to push past High and Preset, so that you don't accidentally get to Strobe and SOS modes, and don't accidentally get to the Select position, which would change your Preset mode.
- Search & Rescue people might need the SOS and Strobe modes, but many other people don’t, and many people would never use those two modes. Maybe you could produce another version of the S1, for "regular people". You could omit the SOS and Strobe modes, so that turning the selector ring to the left gives you Low, Medium, and High.

I agree with all, however I do not think that a thrower is necessary to be available with NW LEDs. But then again, this is a different breed of flashlight that can do more than throw, so NW may be a good addition indeed.

2pcs of the UCL 72.7mm x 1.85mm thick gives 1.48% cut in output. (each one is 0.74%). Original glass is nearly 10%. AR tint is green in colour. No rattle, the bezel screws back on ok but there is a very slightly bigger gap between the bezel cap and body than before. Original glass is 3.5mm and this is 3.7mm, a minor difference of 0.2mm. In reality you won't notice it.

2100 (and anyone else who owns both the Xtar S1 and the Dry), now that you've had both lights for a while, what kinds of things do you use each one for? Do you use one much more than the other?

Does anyone know of a beamshot comparison between the Dry and the S1?

I had both lights. but have S1 only now.

S1 is heavier and larger than Dry(mine was neutral version). I can say S1 is a thrower monster. Wink

Thanks candle lamp. Can you tell me more about what you use the S1 for please? And also why you preferred it over the Dry? One of the things I use my bright lights for is walking my dogs at night in the woods and on trails beside the river. It's completely dark in some places there because of tree cover, so having a lot of light is useful, but it's good if the beam is narrow so that I don't get too much reflection off nearby trees. On the other hand, sometimes there are more open areas, and then I like more flood, so I don't have to "paint" the light around so much.

I already have a decent thrower (5x XR-E light) but the beam is so narrow that it's only really good for seeing far into the distance. For medium distances it requires too much painting. So I'm hoping that the S1 is a decent thrower (significantly better than the Dry), but not so narrow a beam that I'm always painting it around.

I'd also like to know what you put the S1 in when you have it with you but you're not using it.

Hi peteyboy,

The main reason why I like S1 is I can use it on high mode continuously more than 20 minutes. I had measured the surface temp. of the light w/o cooling and got 48 degrees at the head side. I think the light has no big problem for the heat of the body within appr. 20 mins running on high brightness.

It has very bright hot spot and smaller medium size spill beam than Dry.

I don't know if the beam profile is acceptable in a short distance for walking with your dog at night. Maybe you can use it on the lower brightness.

You can see some beamshot relating to S1 here. Hope this is helpful.

http://www.candlepowerforums.com/vb/showthread.php?330637-XTAR-quot-Monster-quot-S1-(3xXM-L-U2-3x18650)-review-runtime-beamshots-etc.

Of course, I like S1 exactly. But I don't have special thing to put it in.

I don't know if the above link is not a problem here.

P.S : Mine is pre-release production, and I've seen the news updated version will be relased.

Thanks very much, candle lamp. Nice review too.