I have that clip. It’s a bit too long for my taste. Also it’s scratched off the anodization on both my 18650 and 18500 tubes, so i’m not too thrilled about it right now.
Would knowing actual LED temperature help thermal management?
I ask because I just learned that you can calculate it from Vf. It would require different firmwares for different lights though.
Best solution is probably a firmware update.
Change the UI as follows:
- 3-clicks - shortcut to 2.5 amps … This is similar to what DrJones did with his lumodrv ramping firmware. Triple-click is easy to access and is helpful to use as a shortcut to another well-used mode. Another option is maybe set this at 3 amps. It might still ramp down at 3 amps but probably not for a few minutes and probably not by much.
- 4-clicks - shortcut to battery tester
- 5-clicks - shortcut to tactical momentary
Everything else can stay the same.
Link does not work…
Does anyone have an estimate as to how long each led can run on turbo before it’s thermally regulated? Or a discharge curve as to the amount of total runtime on its highest setting? I want to choose a flashlight that is amazingly bright but also practical. If it can only sustain turbo for a couple of seconds, then it’s not the light for me. Thanks for your input.
Depends on cell and ambient temperature, but for the 219C it’s 15-20 seconds (from cold) on turbo (before it starts to step down).
The D4 can only sustain turbo for a couple of seconds, it varies with the emitter choice but very short it will be! Amazingly bright in this size will just get amazingly hot, whichever flashlight you choose, and the D4’s well-working thermo-regulatation is as practical as such a light gets.
There’s more settings than just turbo though, still pretty bright and also sustainable, actually for the size the D4 is build very well thermally (i.e. better than an S2+)
You may want a bigger light though, much more heat capacity and heat-shedding surface area.
Forgive my ignorance, as I am not fully comprehending the output graphs posted in the OP, but what is the max sustained lumen output of this light? Am I reading it correctly that it’s only about 150-200 lumen? This can’t be…
In turbo, it seems to be dropping like a lead balloon immediately upon engaging, which, if it’s really about 4000 lumen, that’s understandable, but at what lumen level does it level off?
Like other lights of comparable size (think S2+) D4 can sustain about 1000 lumen without breaking, but it will be way too hot to touch then. I can confirm CRX’s test that between 500 and 600 lumen and hand-cooled it is sustainable. When outside with airflow all flashlights can run brighter without overheating.
Charles Lin, Efest makes a dark purple 18500 1000mAh cell that’s high discharge… it gives me some 3400 lumens on my scratch built Ti/Cu Quad and 3200 lumens in my Mec-Army P16 Quad.
Remember that the temperature regulation works differently on different batteries. The VTC6 for example gets so hot so fast that the regulation corrects it much more than on the Aspire for example.
Here’s both cells on turbo with the temp limit set manually to 43°C.
Sampled every 1/3 second. I’ll overlay output on those tomorrow.
On video, without temperature calibration (subtract 3°C):
VTC6
Aspire
Always a great pleasure to read your interesting and well-presented data, maukka! 
Awesome vids maukka, you are da man :+1:
Another night, another walk, another couple of notes:
- If I have the light off, with some low mode memorized. 2-click to turbo. 1-click to turn off. 1-click to turn on. Result? It forgot the low mode and starts with Turbo. That’s unnecessary, if I want turbo again, I can 2-click again.
- I have a light on some high mode, want much less. Solution? Twist the tail cap back and forth, turn the light on. Result? Nothing happens. You need to wait until it double blinks and then wait some more until you can turn it on.
- It would be more noob-friendly to blink out battery capacity (scale 1-10) rather than voltage. Could be slightly off with 4.35V batteries, but there are few of them…
- Thermal regulation really dims it down. It’s way below 350 mA after turbo and takes very long to recover. It’s better to reset it to 350 mA than wait. That’s 219c/VTC6.
+1
I’m no expert here but have a few lights of all size and although i may have not argued as clearly as djozz, i would have said that this kind of small light should not run much higher then 600 lumens because of heat dissipation - as of today. The 3k/4k lumens extravaganza is just that, a quick burst if need be but only for a few seconds. No magic involved here.
Now, hopefully, one day in the not too distant future… we may have more efficient leds that produce very little heat… and this kind of minor miracle may last much longer then we dare imagine. Pure light, no heat, that would be intense. Could you have imagined a D4 just five years ago? Can’t wait to be ten years older! :smiling_imp:
- The year 2027 -
“Wow, I can’t believe this EDC light steps down to 10000 lumens only after 10 minutes…”
imo No, because the light already has built in protection, read post #1:
About 30 seconds at which point the light drops to 10% output…
Look at the post below by CRX… it depends partly on what thermal regulation setting is being used
See post 958 below, to get some idea. It has been suggested that 600 lumens might hold steady. afaikt there is no way to set the light to 600 lumens, or any other specific lumen level, unless you have a light meter.
you Can set to a NoPWM mode of about 150 lumens:
Post #1
Post #958
Thanks for the videos.
Would be great to see the lumen ouput overlaid on these graphs also :+1:
Hmm… So, if you start at a lower level, what is the highest output it can sustain for a couple minutes? 600 Lumens sounds low? So after two minutes my Zebralight SC600 II would be brighter? I see H2 on the Zebra is about 670 listed output, so maybe around that level?
Yes, I know Efest 18500. However, compared to 18650 vtc6/30q/GA & 18350 Aspire; I expect a good 18500 size battery will do High Discharge: 10~15A, Capacity: 1300~1500 mAh.
The link works on my side…….Try copy & paste