Review: Xtar S1 with curves and outdoor beamshots

It is some sort of regulation, but it does not work as well on the lover brightness, yes this is strange.

As can also be seen from the heat test, heat will reduce output considerable, but I do believe that Selfbuild uses a fan for runtime (like me).

Yup, agreed with heat related problems for HI, but on Low modes I dunno heat will affect :| Xtar need to polish that :bigsmile:

Great review anyway ;) :crown:

HKJ: Is this your website as well?

http://lygte-info.dk/review/Review%20Xtar%20S1%20UK.html

http://lygte-info.dk is in his signature

Yes, and all pictures in the review are hosted on that size.

Just wanted to say thanks for all!!

( and what happens with your XTAR torches? so many review samples you got for free :D )

Mostly they get used in my beamshot comparisons, but sadly not this one (I had a bad day and made a mistake with my power supply).

sorry to hear about your bad day, omg :cry:

after you're done with a torch review, you can keep the torch and dont have to return it, right? They remunerate you with the torches.

Better than a cheque $)

That is the standard deal, it is the same for chargers and batteries.

But if you check the reviews on my website, you will see that many of the light/chargers/batteries are some I bought (I always write a note, when I get the stuff for free).

Great review sir! Thanks very much for the excellent details. Frontpage'd and Sticky'd.

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 absolutely won't notice it.

HKJ, since you've reviewed the S1 and most or all of Xtar's 18650 batteries, would you be able to say which ones are most suitable for use in the S1, for someone who wants the output to stay as high as possible, even if that means less run-time?

You have to look at the voltage sweep for high. This shows that the light as stable output for any voltage above 3.5 volt and it needs 7.5 ampere. Because it uses 3 batteries in parallel you can divide the 7.5 ampere with 3, i.e. 2.5 ampere for each battery.

With these data you can look in my battery summary (or the full comparison, that I will publish soon). You want the discharge down to 3.5 volt, but I only have a 3.4 volt or 3.6 volt. With 2.5 ampere you want somewhere between 2A (cyan) and 3A (yellow).

I.e. the batteries with the longest cyan and yellow bars in both charts are the best.

I would go for the Spark or Xtar 2600, they are best in the 3.4 volt chart (i.e. the light has dimmed slightly).

Swell, thanks very much, HKJ. That explains things perfectly.

HKJ, could you describe this photo a little bit please?

Is the central disc recessed for the 3 MCPCBs or do the MCPCBs sit on the surface?

If the disc is recessed, do the plastic insulators also fit into the recesses?

Are the MCPCBs fastened to the disc, by glue or screws, or are they held in place by the reflector pressing on the plastic insulators?

Are the MCPCBs a standard diameter? (I might some day switch them to NW)

Is the central disc held down by a large threaded ring?

How much mass does the central disc have, and how much surface area does it have in contact with the head (qualitative descriptions)?

thanks very much!

I hope some photos will answer the questions:

I did not see any trace of glue. The MCPCB are 16mm in diameter.

Thanks very much, HKJ. I really appreciate the pictures.

Hmm... it looks like maybe only a small amount of surface area contacts the head when it's assembled. Could you please either confirm, or take a guess, as to which of the five surfaces make solid thermal contact with the head, after the threaded ring is added? Surface #2 should for sure be one of them.

|
1|
|
_2_|
|
3|
|________

4 |
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|
5 |
|
|


Edit: and surface #4 too. I'm asking these nitpicky questions because of all the troubles people had with the early Skyray 3x XM-L with its drop-in design. The original version 0 of that Skyray, and the current Dry, have an excellent thermal path from the LEDs to the head, and the TR-3T6 does too via the threaded drop-in design.

I'm wondering if the low temperature rise at the S1's head, measured by various reviewers, is just due to poor thermal contact between the LED & driver module and the head.

It is clamped between 2 & 4.

1, 3 & 5 is very close to the body, but not clamped in any way.

The reflector is also metal and will transport some heat away from the leds.

Thanks again HKJ. I guess that surface #4 looks fairly big, and I didn't think of the reflector helping to heatsink the LEDs too.

To HKJ or any other S1 owners: How do you disassemble the LED module to access the driver?