Please no 6000K for throw!
Stick with 5000K and below. High color temperatures for throw are useless when there is a lot of dust or moisture in the air. Please HiCri for the flood. I’d say do a 5000K XPL Hi or SST for Throw and a 4000K Nichia or Samsung for the flood.

This is look'n pretty good. The UI and switch (switch is really part of the UI) are very important to me - makes all the difference and so often it's done wrong.

MacLee wrote:

here is beam for test sample, 4000k tint floodlight and 6000k spot

Similar to Nitecore H35. Made like EDC- headlamp, but L shape uncomfortable for use as EDC and too heavy as headlamp

Being 40-50g lighter with 18650 and 1-1.5cm shorter it would be much interesting as headlamp. For 2000lm output(in turbo) not necessary to use 21700. Maximum stable output for such host about 600 lm (with hicri flood , and neutral throw) so it is at least 2h runtime.

Or maybe more interesting… 18650 battery, buck -boost driver , 3500K Hi-cri LED with 60 degree main optic and 30 degree small optic with a deep red LED

Why not several 26650’s on your head?

Does anyone ever used the head lamps they design?

MacLee wrote:

hmm. may consider use both 5000k for main light and floodlight

My vote would be 4000K for flood though.

For weight reduction, adding more finning, and finer finning would help with the heat, as well as reduce weight. I would think that tube design results in excessive weight as well - might consider more cut-in's to reduce weight with the tube. I think the overall design is good - it can be done with a 21700. An example of a very lightweight light is the Skilhunt M200 - I weighed it at 44.6 grams, about the same as an 18650 cell. It has a very thin battery tube wall, thin head with some decent finning in the head.

MacLee wrote:

JaronRH wrote:

Neat design! Can you run both flood and spot at the same time? If so, why not aim for making both LEDs the same tint? (5000-5700k)

Yes, both flood and spot could be turn on at the same time, and adjust different modes when both turn on

Yes please. Same tint. Im a bit Goldilocks what it comes to tints. 5000k is maybe a bit too cool, but 3000k is too warm, so 4000-5000k would be optimal for me. Usage would be biking and gettin flood light at same time also should do nice work when hiking etc. Good amount of lumens and GOOD sustained output is also good thing.

On a second thought: I love the yellowish XP-L Hi 5D and would pay some $ extra to get a cree in the throw section.

Supporting a powerbank feature from a USB-C port makes this very interesting to me, especially if it works with C-C output. This would be great to keep in a backpack in case my phone needs a charge or I need some extra light – for some reason almost all the great powerbank/flashlight combos are huge throwers, which makes them impractical for a backup bag carry. Something as versatile as this would be the opposite.
I don’t think it would replace my usual backpacking setup just due to the lack of redundancy, but it might be a bit lighter overall when you consider that it means you aren’t carrying a separate powerbank.

This light looks nice, a bit heavy, but I would get over it. Agree with most on the non cool white throw.
I would love to see anduril somehow get on this light, even though its not the best headlamp UI

Is that headlamp “clip” going to be removable, or is it a headlamp only

Tom E wrote:

This is look’n pretty good. The UI and switch (switch is really part of the UI) are very important to me – makes all the difference and so often it’s done wrong.

+100

I’d really like to see high-CRI for both emitters, at least as an option. The high-CRI emitter is one of the reasons the FC11 has become my default recommendation to newcomers.

The SST-20 4000K is a very practical throw emitter even if it doesn’t make huge numbers, and Wurkkos is of course already familiar with the LH351D, an excellent choice for a flood emitter.

AEDe wrote:

6500K – please forget about such led! 4000-5000K and the same CCT for both led.

If the clip is sturdy enough amd the price is right, it sounds like a winner to me. Preferably a clip like the FW3A, so it won’t detach.
Nice light!

Im interested to hear a release time.

This light just might be the one that Im looking for if it can sustain good amount of lumens and throws nicely. Flood light is also a really useful bonus.
I wouldnt go too crazy with body colors though. Green with stainless steel bezels or just some other nice earthy two tone would do it for me.

Any idea of the release date?

MacLee wrote:

Not sure about the other two colors, maybe will try the desert tan only small quantity the blue color seems not the one we need as the design

Is that desert tan on first pages picture? Not bad, would love to see how it looks with bezels. Only backside on those pics is visible.
UI seems good enough. Still waiting specs and price. Really interested on this on!

@MacLee:

Mark, I took the liberty to visualize the draft UI you posted in post #1, see below.

Some thoughts and questions...(sorry for this much text but I try to list up everything that came into my mind)

• Do you have any plans to include a ramping mode in HD20's UI? The stepped modes look fine so far. I would recommend a good mode spacing between low, medium, high and turbo. If you consider using the moonlight mode as a totally separate brightness level, I would suggest a mode spacing like 5lm (low), 150-250lm (medium), 600-800lm (high) and 1.600lm (turbo) for spotlight and 5lm (low), 80lm (medium), 250lm (high), 600lm (turbo) for floodlight. Please try to use a sublumen value for the moonlight mode, i.e. 0.5lm would be nice. High mode should be sustainable without any stepdowns.
• If possible in terms of efforts and material costs, please try using a thermal stepdown regulation instead of a fixed timed stepdown as in FC11. In cold ambient conditions HD20 could run on turbo mode much longer. Sofirn has recently introduced new thermal regulations (ATR) in their new drivers (e.g. IF25, IF25A, SP33 V3). They should be able to use the driver's NTP for thermal regulation unless HD20's driver is a complete new design.
• I vote for black and desert tan as anodization colors. The blue color looks somehow a bit cheap and less appealing, especially for a headlight someone would mount onto the forehead. The "army green" tint could be an intriguing look, though. If you still intend to sell a blue version, I would be careful with the lot size to avoid excess stock.
• I fully agree with the majority here to avoid any CCTs > 5.000K. Any tint between 4.000K and 5.000K is fine. If you can, please avoid AR coating on the optics/lenses for the floodlight (LH351D). It has come to BLF's attention that this LED somehow produces greenish tintshift with coated glasses. If the floodlight optic uses a pebble design for light diffusion this problem will probably not appear anyway.
• In terms of the headstrap, please check for a better headstrap than the one Sofirn used for SP40. The cheap rubber mount of SP40 gave me a hard time to handle, fiddling the flashlight into and out of the mount. The headstrap should also include an overhead strap in the middle to improve weight distribution upon the head, especially with a weight of 160g.
• Regarding the USB-C output, please try to incorporate the latest charging circuit revisions that Sofirn used for their LT1 lantern. These changes include two small resistors that enable the USB-C port to be used with type C to type C cables. Without these revisions HD20 can only be charged with type A to type C cables between charger and flashlight. This is nothing mandatory but it has the potential to become a minor nuisance when type C cables will become more common in the next years.

Concerning the UI in particular...

• What LEDs will run using the strobe modes? Flood, spot or both?
• What LEDs will run using the moonlight mode? Flood, spot or both?
• What will actually happen when the battery check is initiated? Will the LEDs blink out the voltage (e.g. 3x short blink, pause, 8x short blink = 3.8V) or will the switch LED indicate the approximate battery status by different colors?

Really good post Lux-Perpetua. Nice community spirit and ice cold knowledge.

needs to have a quick disconnect headband mount