As a keen orienteering runner, I thought H04 would be a good replacement for my H03, but I find this particular terrible. When running in a forest and looking at a map, the blinking is just annoying. And as much as I understand the reasoning behind it, it would be much better if it was an option which can be disabled by the user.
Keep in mind that it is highly subjective and depends on use case a lot.
I am completely fine with how low battery indication works on H04 mini for example, it is convenient and useful to me. But i can totally see how someone might dislike it.
And it works like this with most UI choices. No matter what you do someone is going to dislike it. Including highly configurable UI.
That’s why each time someone gets annoyed by some UI feature, like OP here, and tries to convince everybody that the light is “horrible, do not buy” because of this feature - it always sounds funny to me.
What light did you get instead? ZL are a viable alternative but a little more expensive.
Skilhunt upgraded the UI of the H04 series some time ago (replaced the” A&B Group” UI with just single gruoup UI. I think, the new UI get rid of that blinking of the main LED, only the switch flashes. At least thats how it works on the M200V3 which has similar driver to H04 headlamp.
Just checked manual:
When the battery voltage drops below 3.0V,indicator flash twice every 2 sec,the light
fast flash every 2 Minute at same time.
When the battery voltage drops below 2.7V,the light will cut off.
So its every 2min now.
Ah, just checked their site and you’re all correct there’s new UI. Interestingly there’s also 519A option!
But no mention of CCT 
4500K
Are you honestly surprised nobody has taken you up on your $110 ($99 with your 10% discount) offer for USED lights that can be purchased NEW shipped for $85 USD (on AliExpress)…
If you post them for a proper USED price I’m sure someone would grab them quickly.
Depending on which firmware is loaded on your H04 RC you might be able to change to Mode B (I believe it’s called) that has single-click for off.
Useful resource on the Mode A/B UI: Skilhunt H04 RC Headlamp Review - ZeroAir Reviews
Man they must not teach reading comprehension or how to read graphs in idaho lol. Okay, even assuming LVP was at 3.4V like you say, look at the discharge graph of the Sanyo GA at the lowest current and tell me how much capacity is left at 3.4V.
Edit: note I don’t disagree with you that the blinking every 30 seconds is a bad way to indicate LVP, just that 3.4V is almost empty for a li-ion cell
The RC model makes it easy to measure the voltage of the battery from the charging contacts. With 3.4 V while the light is off the voltage will drop to about 3.1 V at high (and starts flashing).
How far can LiIon be discharged? This sticky covers battery voltage and sag pretty thoroughly. You can also follow two links near the end of the original post. There’s not much capacity left below 3.4 volts. Most cell phones shut down at about 3.3v or even higher. And yes many cell phones charge up to 4.3v or even 4.35v. The Samsung flagship phones and others including iPhone do give you the option to charge to 85% capacity. They do that to extend the batteries useful life.
Plus, different chemistries, not just ICR, INR, etc., but variations within ICR, INR, etc., mean different discharge curves.
I just watch what happens on my Ope when doing a capacity test.
For the majority of the time, it’ll sit at each hundredth for quite a while, eg, 3.72 before dropping to 3.71.
When you hit 3.3V or so, it starts picking up.
By 3.0V, it starts dropping like a rock.
When you’re already at 2.9V or so, it might even start skipping values between samples, eg, 2.83 down to 2.81, then down to 2.78, etc.
Then in only a minute or so, drops so fast that you don’t even catch the value it was last at before it displays the capacity.
Yep, boost is available with the 519A, and yep, 2A per emitter. I don’t think Hank will do those kind of mods for people but I’m sure there’s a way to change a resistor and/or tweak the firmware to get more juice…however, still a small host so that would be a lot of additional heat and may run into issues with thermal stepdown like we see on several other lights. Judging by the three similar boosts I have from him, I’ll bet the turbo/high will still be plenty bright enough even though it’s not as bright as the fet version. That said, gravelmonkey’s input seems valuable as he has both of the lights. I’m not a big headlamp guy (or rather, I prefer center-mounted emitters over right angle models), so while I did consider this one once I saw how chunky it was I knew it wouldn’t get used. I actually like ye olde Black Diamond headlamps still, despite their shortcomings, and on NiMH they can run quite a while….and I like the Wurkkos HD15 but I have that one on the shorty 18350. Not sure why Hank likes the chunk on some lights but it looks like his new 14500 will be the same way. He might just want some more heat sinking or maybe is has something to do with ease of machining.
Can some one just run a test on L1 and L2 modes. How long it will take from LVP warning to off. 5 hours, more?
It is not relevant. How much work are you going to do outside with 3 lumens or 0.5 lumens. Skilhunt says it starts flashing at <20%. Unless you’re stuck in a cave, change the battery or charge it or put on a new light. If you are stuck in a cave with one light and it starts flashing, you should turn it off and think about what you did wrong.
So assuming Skilhunt we should be satisfied with –20% of runtime ? Minus 20% off runtime = –20 % efficiency 
Thank you very much for you guys discussion and opinions on this issue.
The low-voltage reminder function of this series headlamps has been adjusted and improved several times after feedbacks from many users, we are trying to meet the needs of as more as possible.
Now, the low-voltage prompt function of H04 series headlamps is as follows:
When the battery voltage drops below 3.0V,indicator flash twice every 2 sec,the light
fast flash every 2 Minute at same time.
When the battery voltage drops below 2.7V,the light will cut off.
In headlamps next upgrade, we will improve and upgrade this function again, let the main light flashes can be turned off / on, and the main light will no longer flash to indicate in moonlight mode.
This feature will also be reflected in our upcoming H150 new headlamp.
If you have more suggestions, please send email to us, your opinion is very important for us to improve our work.
3 Thanks
Can i get a free samples as a beta tester?
I’d like to volunteer as well. 