Hi!
Haven’t been on this forum in a couple of years.
Currently have a Nitecore NU25 for ultralight backpacking use which is nice, but it’s custom lithium ion & charges via usb, so eventually it won’t be usable.
I have a Skilhunt H03, but it’s just too heavy and overkill for majority of my needs (18650).
What highly efficient 1x14500 headlamps are out there? I’m aware of the Zebralight AA models which look efficient, but kind of bummed out at their price ($60) and lack of 14500 support.
Look at Sofirn HS05? There is also a Manker like it, and Maker also has a 1aaa/10440 if you want even smaller.
I have a very lightweight and cheap 1aa headlamp on order from AliE but it doesn’t take 14500 and is comparatively low lumens (which is fine for my purposes). I can dig up the info if you want it.
If you like your NU25 and the issue is just that its internal battery will someday crap out, you could look into replacement batteries. That means opening the light up and maybe soldering, but here on BLF you are allowed to do that.
You could also check the Skilhunt H03 Mini which is an 18350 version of the regular H03, iirc.
The new manker E03 is pretty light at 36g without battery, and takes 14500.
I got an E03Hii last week. For the money it seems very nice. Lightweight, pretty good ui, I wish moonlight was a little lower with a 14500, but it’s great with a eneloop.
Just to show off a bit (and a preview for my OL challenge build) 
My custom headlamp built to use an 18500 cell, and weighs 21g without cell, 54g with cell.
I have an Acebeam H40 for such purposes. Well built and eats 14500 (only button top) as well.
Unfortunately it has no “true” moonlight and LVP kicks in very early.
Love it
I’ve been using a Thrunite TH20 for some years now as my lightweight headlamp and love it. In fact ended up getting a second one, even though most of the time I’m using a bigger 18650 light. Two TH20, both LED swapped one to 4500k 219b and the other to a 3500k LH351. While the light quality from the 219 is wonderful the 3500k LH351D is very nice and I strongly prefer the floodier output it gives for a headlamp.
The fact is there aren’t so many budget AA headlamp, that are much usefull than flashlights when you need use 2 hands
I’m very happy with my Fenix HM23, and highly recommend it.
Hi nquinn,
I have the exact same need & interest … and can’t believe that my favorite UL lamp still is the ZL H52w (52 not 53!) from 2013. I hiked over the Alps with it in 2020 (7 days) and only used one fully charged 14500, mainly sticking to the low modes of course. The whole system with Headlamp + MYOG comfortable headstrap + 14500 battery weighs 66 g but offers good runtimes + battery indicator and — important — the battery that can be changed (to AA or lithium in the cold). It’s such a shame that the H53 was rather a downgrade… but it’s still a good option for NiMh.
Many other 14500 lamps I know of are much heavier… not available anymore or really IMHO no real improvement compared to the H52 → Parametrek Flashlights . The above mentioned H40 is a good option but my high CRI version of that lamp crashed for some reason and never worked again. Reviews suggest that happened to a number of people and this version basically disappeared from the market. TH20 ist a good option too, but has a very greenish tint and is much heavier than the ZL.
Are other batteries an option? In summertime, when the lamp is only needed an hour a day, I also tried the Lumintop HL AAA for multi day hiking trips (lamp + MYOG strap + lithium AAA = 33 g). It worked ok, but it’s also not available anymore.
Other AAA headlamps don’t seem to weigh much less than the ZL H52 / H53 (like the Manker AAA with 21 g) and you save little on the batteries if you need a bit of runtime (14500: 21g versus AAA Alkaline / NiMh: 12 g). I am not even considering the plastic options that use more than one AAA here.
I also tried several CR2032 options like the Petzl e+LITE but wasn’t very happy with runtime / beam profile and the concept of non-rechargeable batteries in general.
My latest attempt was the Fenix HM51R V. 2 (only available through some Eastern European shops). With the low modes it’s an improvement over the HM50R V. 2 and runs on 16340 batteries but I hated the extremely wide spill beam profile on both the white and red modes (no keeper 
). Same goes for the MC12 of Trustfire… 175° spill ist just too much for hiking / trail running. But in general there seem to be many more new 16340 (and even 18350) options compared to 14500 headlamps. Unfortunately. I really like 14500 because in the low modes runtimes are fine for multiple days and I can use Alkaline, Lithium, NimH and 14500. And with a 3g adapter that whole range with AAA / 10440 size…
Have you found other interesting options in the meantime?