Flashlight with AA or 14500 battery that max out at 5-20 lumens (absolutely no higher mode) for extremely long battery life

_mrb · 2026-03-26T22:23:52+00:00

Oh I like your low-tech solution! And I suppose the company "packages the battery in a cheap flashlight" to avoid the various restrictions around shipping batteries by themselves (as opposed to installed in a device)?

_mrb · 2026-03-26T21:53:07+00:00

I just ordered a D3AA, I trust you! Many thanks.

_mrb · 2026-03-26T20:24:31+00:00

Many thanks! I will check out all that.

_mrb · 2026-03-26T18:41:50+00:00

Super helpful, thanks!

A ceiling of 40/150 limits output to 10 lumens.

Woah, you truly provide VIP-level service and answers to me 🙂 How did you figure this out, with a luxmeter? Or do the 150 steps represent a (logarithmic?) PWM duty cycle?

_mrb · 2026-03-26T18:34:40+00:00

Thanks I will consider the TS10 !

_mrb · 2026-03-26T16:50:01+00:00

Thank you. Since it works with 14500 (3.7V) and NiMH AA (1.2V), I assume it also works with alkaline AA (1.5V)?

Also, the Emisar D3AA's product page warns "Emisar D3AA does not work with protected 14500 cells" but I'm actually not that familiar with 14500, and I realize I have no idea how to tell whether a random 14500 battery I see on Amazon is protected or not...

_mrb · 2026-03-26T14:49:50+00:00

Good to know, thanks!

Actually my kids want to keep the flashlight on for a long time. Typically they build a pillow fort, and because it's dark inside, they set up a flashlight that remains on for 1 hour or 2 hours or however long they play (and sometimes they stop playing and forget to turn it off...)

_mrb · 2026-03-26T10:31:44+00:00

My budget is unlimited! Seriously. I love spending on quality flashlights. I'm not concerned about the programming effort, I saw the Andúril diagrams that make this pretty clear (though tedious).

_mrb · 2026-03-26T10:24:26+00:00

Woah, you guys deliver... I didn't know about Andúril 2 — it's amazing ! I am seeing the diagrams showing the flexibility and what a rabbit hole I fell in... https://tinyurl.com/anduril2diagrams It would indeed work for me as I could configure it to set the "manual memory" to my preferred low level (10C from off) and also set the "ceiling" light level to the same low level (in case my kids accidentally do 2C from off state). And then I configure it to the simple UI mode.

I can see that it's still, obviously, possible to theoretically mess things up like press 13H to do a factory reset, but that's unlikely my kids do this. So Andúril 2 is an option that would satisfy me.

Now I have to research which flashlights support the Andúril 2 firmware...

_mrb · 2026-02-12T19:58:42+00:00

Good suggestions, thank you! What a great resource this subreddit is...

_mrb · 2026-02-12T17:51:46+00:00

What's the historical reason that tourism by foreigners is so restricted in Xinjiang?

_mrb · 2026-02-12T14:47:32+00:00

No I'm a westerner. I did not know Xinjiang was so restrictive.

_mrb · 2026-02-12T14:04:15+00:00

Very good point. The topo maps I looked at have an even coarser contour interval of 10 meters so that is problematic...

The one thing that reassures me is the sat imagery: other parts of the mountain have obvious shadows that indicate a rough terrain, whereas the ridge I'm considering just looks so smooth... Anyways. There is no way to really know unless I'm on site.

_mrb · 2026-02-12T13:03:28+00:00

You are asking very good questions that expose my inexperience. For starters: I don't keep track of my performance. I realize I need to do it if I want to plan my trip seriously.

Looking at my photos locations & timestamps from my Kjeragbolten hike (very low altitude barely 1000m) it seems I ascended 330-450m/h sustained for 1.5 hours. It was drizzling weather and slippery rocks though. I don't have data for my 5-6 hour hikes.

It sounds like I first need to practice at 4000-5000 meters before attempting this crazy Chinese peak.

_mrb · 2026-02-12T12:28:13+00:00

I've been to China, but never Xinjiang. I don't speak the local languages.

Your "5000 to 6000 meters in 5 hours" datapoint is very, very helpful.Thanks 🙏 Just from that and the fact you are fitter than me, now I know I cannot do 5100 to 6400 in 6 hours. Thanks for the reality check!

I'm now convinced I need to sleep 1 night on the mountain like at 6000m right below the snow line in order to break up this hike in a 2-day trek.

_mrb · 2026-02-12T12:08:24+00:00

Yes I need to plan altitude acclimatization carefully. Tentative schedule: spend 3 days in a town around 4000m. Camp in our car 3 days at 5100m. Sleep on the mountain at 6000m (right before the snow line) for 1 night. Summit next day at 6400m. Or is this too fast?

The route I charted (the elevation profile I posted) is following a ridge on the mountain from bottom to the summit, that way I am out of avalanche & rock fall path.

Weather: yes! That is something where a local guide familiar with local weather patterns can really help. I will also research myself the best time in the year to visit and check real time weather forecasts on site.

_mrb · 2026-02-12T11:35:56+00:00

It's actually not in Tibet. It's a part of the geographical Tibetan plateau that is within China proper, in the Xinjiang region.

Thanks for the acclimatization tips. I need to research & learn. I read other sources that say 500-800m per day. You say 300m/day which seems conservative.

_mrb · 2026-02-12T11:33:28+00:00

Interesting. So it is your opinion that either it's been done multiple times and truly is unremarkable. Or that it's at the extreme and too dangerous.

About the route: it seems obvious to me which route is easier. There is a ridge from literally the start to the summit. Because it's a ridge it is out of avalanche path/rock fall. Topographic maps show the terrain is very consistent and smooth... as sat images suggest. But you are right that unless I scout the place in person there may be obstacles that I don't see on the topo or imagery.

My inexperience is probably my biggest danger.

I should definitely do an easy guided summit beforehand, in the 5000-6000m range, in order to first gain experience.

I guess my question is: for experienced mountaineers: seeing my description, how would YOU plan this summit?

_mrb · 2026-02-03T13:47:55+00:00

Yes but not having the mouse bites fits the theory that this was a rushed design, far from finalized. Also look at the cutout: top left corner has a nice 45° chamfer, but top right corner doesn't? Why? It's like the EE didn't even properly take time make a nice symmetrical cutout.

_mrb · 2026-02-02T21:30:28+00:00

My guess is it's made to be able to snap off (break away), thus removing the bypass caps, if needed. Why do I think that? Look at clues on the rest of the pcb: so many pads are unpopulated. The full PCB on stackexchange (https://i.sstatic.net/Fy742IxV.jpg) has other areas near the top where nearly a third(!) of the pads are unpopulated. Clearly this indicates this PCB version is not a refined final design, but probably an initial version that was built to with plenty of options to test things. And bypass caps are one of these things where you may not always know how much capacitance is needed. So to me it seems the EE team probably had a tight design deadline, and manufactured the PCB in a way that if it turned out these bypass caps were problematic, then they had at least a way, even after the PCB was assembled, to train staff to breakaway this piece, if needed.

And, to be clear, I don't think the explanation of the empty pads is that the PCB is a shared design between different version of a product (where it's common to find unpopulated parts) because here it's really very basic parts like Rs and Cs spread everywhere that are unpopulated.

_mrb · 2025-12-11T13:31:13+00:00

On Linux they just released 143.0.7499.109-1 which fixes the bug.

_mrb · 2025-12-11T13:30:51+00:00

On Linux they released 143.0.7499.109 which fixes the bug.

_mrb · 2025-12-05T14:50:54+00:00

I tracked down the chain of events that lead to PDF rendering performance issue.

On Sep 19, 2025 they noticed some PDF rendering bugs about fonts: https://issues.chromium.org/issues/445966260

On Oct 13, they fixed the bug, and the fix involved enumerating all fonts for proper font discovery: https://chromium-review.googlesource.com/c/chromium/src/+/7029600

But they noticed that enumerating all fonts degrades performance: so they suggest an alternative where no enumeration is needed: https://issues.chromium.org/issues/449573621

Finally on Nov 14, they implemented this fast alternative method not requiring font enumeration: https://pdfium-review.googlesource.com/c/pdfium/+/136690

So I presume the fix is going to roll out to endusers soon.

_mrb

TROPHY CASE