The head of the light isn’t safe to handle after 10 seconds. I think I’ll use GA cells instead to get more runtime/less heat.
Someone should make a light like this with a plastic or rubber cage round the head. The cage should be sufficient to prevent the user’s fingers from directly contacting the metal in the head, while having slits to allow heat to escape.
Getting too hot to touch in 10 seconds sounds a lot like my modded DQG Tiny III 18650 with FET driver. It became such a problem that I made an external finned aluminum heatsink. Even that didn’t solve the problem, but then I painted the heatsink with paint and super-glue and installed a new button cover made out of Sugru. The light still gets too hot to touch, but now takes more like a minute to get there instead of 10 seconds. The finish on the light looks awful though.
Here’s a picture with the 18350 tube. It’s almost the same size as the 4sevens mini turbo mkii!
Measured it with Aspire 18350 and it pulled 13.7A. Impressive.
Thank you TK for your nice and useful review! :+1: I like the green one. 
The road has led you to an interesting place — welcome to BLF!
It’s not often that anyone spends their first post on one of my threads. 
After a couple minor tweaks, I tried a runtime test on turbo with a full 25R cell until LVP kicked in.
I had the thermal limit set to 45 C (ish) and pointed a fan at it the whole time. Output stayed fairly close to a stable level after the initial peak, but it actually got slightly brighter over time overall. I suspect this might be due to the cell voltage getting closer to the emitter Vf, so there may have been less heat. Toward the end it also becomes very clear that the thermal regulation is fighting against the typical direct-drive sag curve.
So… aside from being a little bumpy, thermal regulation seems to be working pretty well.
Output is about 900lm with active cooling. Could you also measure output with out cooling?
Test 5 looks great! And yes, a version minus fan cooling and plus hand cooling seems most realistic to me. And given the nature of this light (hotrod) I would not mind the thermal limit to be a bit over 50 degrees for some higher regulated output.
What kind of stable output are we looking at in test5 btw? My guess would be 600-ish lumen?
Thanks for the fine review.
I prefer the size, tint, beam and UI of the Nichia D4 much more than any of the Manker, Astrolux or similar lights popular here. I rarely use them because the UI just isn’t simple enough for simple me.
Double-click the D4 and you will immediately see more light than you think possible from anything this size. Within seconds it will be too hot to hold.
But use the ramping, and, ah, you can get whatever level is perfect for you.
The Nichia tint and beam are just right for walking the dogs in the dark. The beam is floody and the tint seems neither too yellow or white — but just right.
I am using an unprotected 3500 mAh 18650 I purchased from ZebraLight. Lack of a clip is a nit as is the absence of more knurling. I added the deep carry pocket clip available from Richard for $1.10.
The 18650 body is small but large enough to comfortably hold. I passed on the 18350 body.
Darn good light — eager to see what’s next.
This active-cooling test was just a sanity check to make sure the regulation doesn’t do anything dumb. The 45 C limit was arbitrary. The thermal ceiling will be user-configurable, so you can change its stable output level by changing the temperature limit.
Most likely, the calibration procedure will be:
- Fast-click 10 times from off, then hold the button on 11th click.
- Light comes on at a low mode.
- To disable thermal regulation (or set it to a very high temperature), let go of the button now. Otherwise, keep holding.
- Light goes up to maximum.
- Keep holding until the light feels hot.
- Let go of the button to set the thermal ceiling.
Attiny85 chips use un-calibrated thermal sensors, so a factory default value will be inconsistent. It seems best for the default to err on the safe (low) side, with a config option so the user can set it to whatever they like.
Done. Had been posted there already, though.
Is there any word about 18500 tubes becoming available.?
Mt. Electronics for U.S. should be getting his order of Aspire 18350 soon,
I’m not sure. I don’t trust the sensor on my phone to give me numbers which are accurate in an absolute sense… only relative output.
So, 600-ish seems like a decent estimate; I don’t have a better guess.
Just a thought that occurred to me. Let’s say 600 lumens is what the light can output comfortably and with stability:
1 click from off = low
2 clicks from off = 600 ish lumen
3 clicks from off = FET turbo
Easy access to a nice high mode of 600 lumens, and slightly more effort is needed for the FET turbo, which is reaaally a burst mode. Just a thought, and certainly not a request.
hIKARInoob 3 clicks …??.. :+1: 
Edit: Beacon mode, would be nice if the light emitted was at a higher level or user defined like the M43, I know you don’t own one, but by holding down on switch will increase beacon light output and a much better brighter flash, maybe a slight bit more speed in between flashes also, counting the flashes in battery level is so perfect, but can’t for the life of me figure out the flashes for temp check, 10 degree Celsius per flash, starts when very hot hot at 4 flashes but as it cools will then start a second group of flashes like the bat check, so not understanding what each group represents, or why I am wondering about it actually, when it’s hot it is real hot and when it’s cool I can put it back in my pocket, no need to watch temp flashes I suppose, just there so had to look at it and try to understand.
Yeah… I mean this light is just stupid bright that it gets too hot in, what 30 seconds or less? So this output is purely for wow or burst use. And that is perfectly fine, but personally I consider this output for my taste “outside regular use of flashlight”, so I wouldn’t mind if this output is only activated with additional effort so to speak. Especially because this is an EDC light. Maybe the idea is comparable to turbo and turbo max for the X7.
Surely people still prefer a single click to turbo for this light; to each his/her own of course.
Reminds me of my smartphone telling me that it is raining today. And I’m like thankfully I have windows in my house, so I can look outside to see what the weather is like… Not really high tech… but it gets the job done…
Only issue I think with the 3 click idea is that it would then cause TK to have to adjust all the other clicks since 3 click now is bat check, but nice idea I think, could be double click from off to high then double click again to fet turbo …?
Ha Ha Ha, to funny, I know what your saying, phone tells me stupid things like that and makes me wonder why do I own this thing, my old flip phone worked just fine, until the phone company said I had to buy a new phone since my flip was so old it was the equivalent of the rotary dial phones, I liked them to… ha ha,
I am not sure those phones are that smart but they are capable of scaring me sometimes, like how did this phone know that, and it wants me to turn on photo recognition, ha I don’t think so, making me paranoid now…
Oh no no no, I don’t want anyone change anything because I said something: it’s just me thinking loud…
M43’s UI1 is also great for this light when it comes to press and hold for momentary turbo (no ramping then). That would work for me as well.