Thank you very much for this well documented modding !
I’ll surely do the same, but I have to order the short A6 tube before 
Thanks for the info lads!
The shorter tube is cool for EDC use.
I would stick to my 18650 just because when i use a headlamp its on for a while. But if your fishing and just need like a basic low light setting so people can spot you and dont want the extra weight its a great mod!
I did swap the LED as it had a noticeable green yellow tint probably 3B or 3C
replaced with a XML2 U3-3D from intl outdoor
http://intl-outdoor.com/cree-xml2-u3-3d-bare-led-p-904.html
I am very pleased with this batch already modded one into my Nitecore P12
There are nice things to report and I did some measurements for modding
the front glass is 17mm wide and 1mm thick,
ecxactly the same as my Jetbeam Jet-1 MK so I got an AR one inside
the driver uses a 0.082 Ohm resistor for current sense, so it could be modded easily
the Star in it has 15mm size and is a true DTP, so no filing down a Noctigon needed
there are markings on the back of the star looking like the footprint
it is flat with some marks of machining
sanded 5 seconds with little press with 600 sandpaper, see its almost flat, the edges are rounded towards the LED side
sanded down 10 more seconds and all machining marks gone
quick polish with 1500 and 5000 sandpaper
In the head the heat paste is evenly across the whole star and also squeezed out on all sides
The head has about 15mm flat machined surface it looks really bad in the picture but in real its almost flat
Reflowing the LED
first heat it up on my induction stove with a 10mm iron plate and 5mm aluminium plate with thermal paste on top of it, till the solder melts
then removing old solder with a qtip and regulating the heat down
the LED is also heated up on a clean part of the metal plate
adding Sn60Pb37Ag3 rosin flux core solder or solder paste, the 0,5mm solder wire is not easy to melt as the temperature is not much above the melt point
I use the one with lead as its melting point is lower and thats less stress for the emitter
placing the hot star on it, let it pull on its own in the centered position
then tap on the star to push out solder to close the tiny gap to increase heat transfer
and this makes all 3 pads covered on 100% of the surface with solder
putting Arctic silver on the body, was too much but it will squeeze out
placing the Star in the head, it is a bit bigger than the anodized hole so I had to put it in sideways, thats why the star is not round all the way
the arctic silver squeezed out at the holes, but wasnt enough to do on the rounded edges
Nice than u for posting the mod very usefull
I have done several mods to mine as well.
1) Added a second magnet so now the magnet is like 3-4x as strong
2) Did the 18350 battery tube mod, combined the light can hold it’s own weight from only the head of a screw (althought currently running a 16340)!
Picture is me cutting boxes to wall hang a TV.
3) Swapped the emitter with nichia 219c 4000k http://www.kaidomain.com/p/S026300.Nichia-219C-Neutral-White-4000K-CRI92-LED-Emitter-with-KDLIGHT-3535-16-16mm-x-1_5mm-DTP-Copper-MCPCB-(~~1-pc~~)
The emitter on the board was the right height and fit in the head with no sanding (tight fit though!) The optic still presses on the MCPCB and the optic still screws down perfect. However of the optic is made for a larger LED, although the pressure seems to be holding it in place and the board does not really have much room to move (well maybe a little)…
It seems to work fine like it is, but does anyone know which 219c TIR I could replace the stock one with? Anyone know what the stock one even is?
Thanks!
I’m running a 4000k 219c in mine. So far everything has been good. Still just a nice floody light. The LED has to be manually centered. I got the emitter on a 16mm board from Kaidomain. The Kaidomain boards may be a bit thinner than noctigon boards (At least my tripple was), but they are still direct thermal path and the single emitter boards are also gold plated I think. Interestingly the TIR makes the LED appear more white and less creamy than my other lights with reflectors and tripple optics using 4000k 219c emitters). Now it could be tint lottery but I kinda doubt it as I have the same KD stuff in them.
I had an issue with the U4 neutral white that came in mine. When using it in the yard the tall grass would make my eyes go buggy, might have something to do with the tint, and TIR combination but I know it made me feel kinda funny when trying to walk in tall grass. I know it sounds weird but the only other time I have felt strange while moving and using a light is with old lights with poor PWM. I no longer get this feeling with the nichia 219c 4000k, and colors render much better, of course I lost come brightness, but it’s still very bright and usable. I absolutely love this headlamp now that the 219C in there. It may not be my fanciest, or prettiest light, but functionally it’s amazing now!
The stronger magnet made it was more useful too.
Now I’m contemplating cutting off the top headband strap rubber (but I can see it being useful if running I guess). I dunno, I’m not a fan of over the top of the head straps…
Just buy another band with just one strap, they are cheap!
I found one for $3 but there was a $10 shipping charge. Have any suggestions? I'm probably searching for the wrong term or something.
in US Zebralight has a nice headband with free shipping
this one will work with short tube mod nicely
Or buy an original skilhunt one you cut off the upper part
If you do the headband through the front where the light is or attach both only to the side
it has a lot more grip on your head not moving while running
Because most of the silicone surface exposed to your forehead
Honestly cutting the upper part off and having the whole silicone stick to my forehead it feels more secure than with over the top and original position of the headband covering most of the silicone
You dont have to break it. The top band will slide out?
The band slide out, but it looks odd and I dont need the top band bcs the light sits very tight with the full silicone surface on my head
Configure the headband like this
or let it be through the lights holders as well, so the lights sits tighter
Received one 2 days ago. Feels very good for the price. Light, nice tint & flood, simple UI.
I have an H51C I tried to put it in that band and it's a bit tight (needs to hands to rotate the light), but maybe it would loosen up? I guess I need to check the diameter of the battery tube when I get home. The fasttech one looks nice if it will fit.
My H03 vs foam. Foam lost 
LOL TIR optics are fun for that
Even my Olight S1 can do that, always a cool trick to show to friends 
Does anyone know what’s the longest 18650 the H03 accommodates? Just ordered the headlamp and wonder if my Keeppower 3400s at 69mm will fit. Thanks.
- TXG
I use protected ncr b’s in mine with no problem. H03 has 2 springs (+ and - side of the battery) so I guess it can take
any size of 18650 batteries.
my panny 18650B fit well with 70.2mm
I measured the light and there would fit up to 71mm long cells