Which physics? Aristotelian? Newtonian? Einsteinian? Quantum Mechanical?
You see, all of them are “logical”. But as they start from different assumptions, they arrive at different results. And even the last two (which haven’t been falsified yet) arrive at different results when applied to the same situation.
Thanks! And good luck with"physics" – I’m under the impression we’re both going to need it! 
I don’t need onboard charging. I would rather the light be compatible with AA batteries. Will the straight model only be available with tail switch? I think dual switches is un-necessary. Tail switch only would be nice to be different than SP10
Thank you all. I think I would be more willing to give up USB C charging now and find a suitable 14500 battery with a charging port. At the same time, I also hope to improve and implement a regular driver here. I don’t know if there is a ready-made program, which is compatible with AA/14500 and supports constant current circuits.
At the same time, the AUX light can also run.
It doesn’t seem like an easy job
I don’t have one, but I hear Sofirn’s SP10 Pro is compatible with AA/14500 and uses a constant current circuit (a boost driver) and runs Anduril, so I’m pretty sure the job is already done for you (at least in terms of finding a “ready-made program”).
aha, yes, SP10PRO is work both AA/14500 , the point is loose the control of aux leds 
The SP10 driver isn’t strictly speaking regulated (on AA) i.e constant current since it’s a constant voltage converter with PWM dimming, the current appears regulated on AA because at constant voltage the LED current vary only a bit with heat (lowers the Vf). A LED with different Vf would draw a different amount of current.
With li-ion it behaves like a FET driver, i.e the current varies with the input voltage.
Thanks for the info, I didn’t know that.
Other flashlights with integrated charging and support for Li-ion and NiMH, for example Skilhunt H150, simply don’t charge if the charger is connected with a NiMH battery. Li-ion below 2.5 V shouldn’t be charged anyway. So the logic is simple: Voltage above 2.5 V, start charging. If it is below, do nothing.
Can the AUX leds indicate battery charge?
Hoping the AA version will get Anduril or at least a decent moonlight mode with shortcuts to moonlight and turbo.
Do we really need AUX LEDs on a headlight? Obviously my vote would be a resounding NO !
What does “need” have to do with any of this?
Sure, we cannot ignore the “OOOOOO, OOOOO, SHINY” aspect of human nature. Especially where marketing is so important in the formula.
So maybe a better question would be, why not just ditch the aux LEDs? Make the design much simpler and potentially better without giving up anything in the way of utility. Maybe I am a flashlight Scrooge… but in full discloser, the AUX lighting on all of my flashlights that have the “feature” is turned off.
Oh you know the need. The primal urge to have one more.
Like my need for pretty magenta aux lights.
In most aspects I am a libertarian… If one likes them… great. But would the lack of AUX LEDs on a headlight keep you from buying it?
I have a bunch of headlights. None have AUX LEDs, I can’t say that has ever kept me from using any of them when I just need light.
I prefer lights that make their location known in the dark.
I like RGB voltage for checking the battery level at a glance, on a headlamp it can be checked when wearing it by turning it off momentarily and checking the reflected color on the hand.
This doesn’t necessarily cannibalise on other features, it mostly increases the cost a little because more assembly, I even added front RGB aux on several reflector based lights with a very simple solution (flex board).
I used to do that too, but since I started turning it on for my 8C_Quick_Aux_Switch mod, I confess I have been leaving them on more and more… it really helps to find the light by the bedside in the middle of the night, for example.
Yes, yes, yes.
Out of most design choices, an efficient CC buck(/boost) driver is most important for a 14500 headlamp for me.
The battery is already so small for a headlamp that is used for extended periods. Every extra minute of runtime matters. Additionally, you can avoid uncomfortable heat, and have higher sustained lumens, both critical for a headlamp.
I skipped the Skilhunt H150 because it is no more efficient (on a 14500) than the linear driver in my Emisar D2, which at least is a dual channel Andruil light.