Thanks a lot for the interesting summary about LH351C, adam7027. Maybe there's a chance that Sofirn will try testing this LED. The important step to make is that they would need to order it in a reasonable amount and use it for more than only one flashlight. Moreover, they would need to check if it's available at all. The only Samsung LED they were able to source so far was LH351D 5.000K 90CRI. I wish they were able to source at least 4.000K, too. I have some lights here with LH351D 4.000K 70CRI and - to my surprise - their beam quality looks nowhere greenish at all. The 70CRI's efficiency gets close to XP-L2 but with a much better tint in a reflector with less artifacts.
Anyway, without wishing to anticipate the odds look good that Sofirn will do their best to implement the draft UI illustrated in this thread.
I am indeed refrencing the tint ramping from the lt1, and honestly would find that far more preferable. The idea of being able to blend flood, and throw, and then have it remeber it for that brightness would be a wonderfull thing, and tbh, if this doesnt go that route, i might just build something that does that myself.
Thunite and Olight UIs both do this, as well an Anuduril/Narsil lights (they ramp down instead of starting the mode cycle). Wurkkos FC11 ramps down from turbo on hold as well, and I believe it’s how the Sofirn side-switch lights other than the SP10S operate as well.
It doesn’t return you to the previous brightness (if you go from on to turbo) but starts the mode cycle at the lowest non-moonlight mode and cycles up until you release.
For me personally not turning off from a single click in any setting is a downside for any light. Having to click, wait, then click again to turn off from turbo on my YLP Unicorn (because I forget to use the weird click+hold for off shortcut that only works in turbo) mars an otherwise fantastic UI.
I would not be upset with a 70 or 80 CRI Samsung emitter for the “spot” function. It cannot have worse tint/rainbow than XP-L2 and probably not SST-20 5000K either. SST-20 5K should be fine too, still much better beam and tint than the XP-G3 many other lights with the spot/flood combo are using.
……yes, that is the point about size and weight when we decide to use a 21700, for a input and output 21700 with more power and runtime…
Power and runtime depend on much more factors. For example from driver efficiency. So what kind of driver you will use?
As far as I was told, HD20's driver will use FET. The charging currents are 2A (recharging battery) and 1A (reverse charging from battery to external device). Please note that this is yet to be confirmed by Wurkkos/Sofirn.
I like the choice of LEDs and the UI, I also like the design of the flashlight, I would like to be made in dark gray.
I know that there are flashlights that are regulated, and others that are not. I would be very interested if this flashlight had a good regulation. To give a good example, the Nitecore HC35 is capable of keeping 800 lumens totally stable for almost 4 hours straight with a 5000mah 21700, I would love for this Wukkos to do something similar. If this have a good regulation and a good price, No doubt, i would buy it.
Not sure if the C8G driver is appropriate here. It is designed to drive a 12V XHP35 HI emitter. The first batch I tested had a rather mediocre ramping curve when increasing the brightness. The current applied to the XHP35 HI was about 1.7A only, leaving a lot of potential unused. Moreover, thermal regulation acted way too early on this light. Fortunately, both Wurkkos and Sofirn have agreed to raise the thermal threshold for HD20 to 55°C in return for better performance/longer runtimes on Turbo/High mode. As far as I was told HD20 will be using an FET driver, i.e. no boost driver with full stabilization.
I’ll take CC linear running on a FET + sense resistor or similar over PWM’ed linear chips any day as long as there is a sub-lumen mode.
Once a cells voltage under load drops below the Vf of your chosen output it will drop anyway. Only a sufficiently low Vf emitter and buck driver, or boost/buck-boost will achieve what I see so many in this community call “regulation”.
If a flashlight has any electronics that control the flow of electricity in at least one mode, it is “regulated”.
I don’t really understand the benefit of defined steps to lower modes when cell voltage drops vs this. Either has the same end result of higher modes losing max output as the cell drains, its why I choose lights with boost drivers whenever possible… because that or multi-cell + buck are the only ways to avoid it.
the drain down to 2.65V is excessive. Most of our firmware triggers LVP at around 3.2 - 3.0V. Looks like this light has no LVP
3.4V down to 3.0V is a significant drop, > 50%. If you look at a normal drain from 4.2V down to 3.4V, the lumens drops in half. That's about right, and matches what many lights use as "Turbo" to "High". 3.4V to 3.0V is a small percentage of the cell range and happens quickly - refer to discharge curves
lower modes are typically in the 1-500 range anyway, still quite relevant. Also lower modes could be using a low channel having better efficiency that the FET shown in the graph
This graph is typical of most of our FET based drivers running on only the full max FET.