Hi, i am new to flashlights. I would like to mod my cheap chinese dental headlamp. Can you please confirm my buy list or push me into right direction?
I understand i need high cri, neutral color LED, so i chose nichia NVSW219BT-V1 5700K CRI92 on copper http://www.kaidomain.com/p/S026480.Nichia-NVSW219BT-V1-5700K-CRI92-LED-Emitter-with-KDLIGHT-3535-20-20mm-x-1_5mm-DTP-Copper-MCPCB Do you have better suggestions?
I am not sure about which driver to use, i don’t need modes, only the most possible lumens with reasonable heat production. Could this do the job?
https://www.fasttech.com/products/3647300 I am extrapolating from this thread emitter test: Nichia 219B V1 4000K 93CRI Direct drive from single 18650 is bad idea,right?
My plan is to use one 18650 and original optics. Thanks for your time
I think that your led and driver combination is a good choice. I’m just a bit worried about the optic, it may be specific for the XR-E led (which is the led that is currently in the lamp), but it may be fine anyway 
5700K is generally not considered ‘neutral’ but more towards ‘cool’.
The optic is fine, but you need a centring gasket / adapter ring.
You need this kind:
http://www.kaidomain.com/p/S023947.XM-L-Reflector-to-XP-G-XP-E-Reflector-Converter-Adapters-10-pcs
Fits around 3535 LEDs (like XP-G and 219 etc.) and inside the optic (Same size as XR-E metal ring).
It will probably fit a little too tight in the optic, small cracks may occur in the base of the optic, but doesn’t influence the workings.
When you ruin the optic:
http://www.ebay.com/itm/361775095483
I think those are the same.
≈20% more output at that driving current VS the 219B-V1; isn't it? And slightly longer runtime because of its lower Vf. Different colour temperature, of course. 
Cheers ^:)
The 219B-V1 has as low a Vf as the 219C, it just depends on the exact bin you get.
I wouldn’t recommend that driver. 1750mA is quite a lot for that headlamp, the casing looks like it’s made out of plastic? Also, despite the description saying it has overdischarge protection, I doubt it has.
I reckoned that it was the small (SOT23-size?) component on the driver that may take care of the LVP? (no real expertise here btw). I agree that a plastic housing does not combine well with 1750 mA.
I have to admit I totally overlooked that one. So yeah, it might as well have LVP, probably has as they’re saying so. I took another look at the housing, now I think it’s most likely anodized aluminium, I can see some scrapes in the ano at the threads. Sorry for bringing that up. But still, I think that new LED+driver-configuration would produce quite a lot more heat than the original, can always remove some of the AMC7135’s though.
djozz, jerommel: Thanks for mentioning that adapter ring for optics, i am adding it to the list.
barkuti: I am not sure about 219C color, all medical led i have ever seen was close to 6000K, but maybe i will buy both and try what tint i like better and the other one i can use for EDC.
chouster: The case is made of metal, but you are right because it was quite hot also with current LED. Maybe 4 amc regulator? http://www.kaidomain.com/p/S024830.Nanjg-111-3_0V-4_2V-4-x-AMC7135-1400mA-1-Mode-LED-Driver-Circuit-Board
I need to read more about discharging protection i thought it is contained in protected 18650…
dr.nu11, in your opening post you linked the 219B-V1 on 20mm board (and I lemminged with the 219C over 20mm MCPCB). Please notice, though, that the lamp uses 16mm board. Just in case.
At what current is the XR-E driven? If cooling is a problem, unless you can mod/extend the case maybe you should stick with the same or little above stock driving current. You'll have more output and way improved rendering quality in any case. 
Cheers ^:)
I think for a headlamp with that optic 700mA would be enough for close range.
Thanks for your advices, i ordered both nichias- B and C at 16mmPCB (my mystake), and 700 and 1000mA drivers. Current LED runs only at about 300mA, so 700 could be enought and second one driver and less nice tint nichia i am going to use for some EDC project. I will update as soon as parts arrives.
In the photos above, it seems to me that XR-E led is on 16mm. You did right.
Saludos ^:)