More good news from the Anduril thread, especially for “blinkers” 
: there is Low Voltage Protection specifically for the aux and button LED. LVP means at 2.8 V the aux/button LED should turn off.
Note that for lights with single-color aux LED like this Wurkkos TS21, the protection is for blinking mode only, NOT dim mode (strange isn’t it?).
I don’t have a chance to test yet, but if you have any battery that dips to 2.8 v level please check to see if it works.
Sorry. Ignore. (people dont like deleted comments)
cannga made me buy a 219C 5000k ts21 to play around and lo and behold.
It’s the silver version, freshly bought WK22H0515KK
Comes with 3 flashing pads and 0614 attiny1616 firmware. This is a very nice surprise!
Seems like the newer TS21 versions will be easily flashable. TS10 bottom to compare.
Haha I am “sorry” to have caused anyone to spend $. Still by far among the least costly of all hobbies though. 
And… the fun is more than worth it.
IMHO, this is a light one buys for the “reference” LED that somehow Wurkkos lucks into (just kidding). The beam is on the cold side but still a must-have for collectors because of CCT (5000k) and Duv (on-BBL neutral). The +prototype “daylight neutral tint+”. R9080, NO tint shift.
Have fun and please share your experience. Sound like you are experienced with flashing firmware, something that I know nothing about, but I’m sure other readers would appreciate.
I guess that explains why the silver 219C is way more expensive than the first ones that came out. It’s more than just a new color or new stocks but rather a surprising upgrade.
(More good news for TS21 owners who use blinking button mode.) Because it’s not possible to know exactly the parasitic drain of the blinking mode, I left 3 Anduril lights alone for 3 weeks and measure voltage drop. The 3 lights are 2 Sofirn IF25a’s (High and Dim mode) and the Wurkkos TS21 (Blink mode).
Anduril Dim Button (~100 µA drain measured): 0.079 volt
Anduril Blink Button (unknown): 0.112 (so it seems blink mode is about between dim and bright Anduril mode)
Anduril Bright Button (~1.5 mA drain measured): 0.164
Convoy S21D Blue Metal Button (4.1v: 9.4 mA , at 3v: 2.74 mA): 0.067
Before you cry bloody murder, yes I am aware relationship between voltage drop and consumption varies among batteries, but this is best I could do as an amateur to test the blinking mode. (It didn’t help my cause that I forgot to use the same battery brand for the tested lights 
.) So please take this as a rough GUESSTIMATE. And if you have time do the same test so I could confirm my result.
Exemplary Convoy number but doesn’t make sense if you compare it against specs from Simon. I am sure of my result though because I have made measurements at intervals in between and it has matched Anduril Dim step by step. Nevertheless I’d like to repeat test; is it one more reason to love Convoy?
I agree that the Convoy numbers don't make sense, but not because of specs from Simon.
According to the numbers above, the Convoy drain is above 2mA at all times, compared to Anduril bright button at 1.5mA. Despite the higher drain, the drop in voltage is almost 3x lower.
Another reason the numbers don't make sense to me: let's assume the best case, that the Convoy drains only 2.74mA constantly. Then over a three-week period, the amount of capacity drained is at least 2.74*24*7*3=1380mAh. This is between 1/3 and 1/4 of the total capacity of a 21700, which should drop the voltage much more than 0.067V.
I feel that I might be misunderstanding some parts of your post, but am unsure--any clarification would be appreciated!
BTW, my S2+ with blue rubber button always drains less than 2mA; below around 3.9V, the drain is low enough to be undetectable by my multimeter with 1mA resolution. My orange button drains less than 4mA.
Thanks for the comments. Another set of “raw” numbers - from 8/27 to 9/21:
Sofirn Bright drops 1.5*24*7*3=756mAh
Voltage drop 4.192 - 4.028=0.164v
Does this one make sense?
A couple things I’m thinking:
first is that the voltage drop is not linear - very flat at top,
second, the blue light draw in my S21D is neither of Simon’s spec, and less than 2.74mA. Not as easy to measure but I’ll try later.
third, thanks to your number 2mA, does it mean Simon’s specs below on Aliexpress are just wrong? I maybe should ask him.
fourth and probably most important, I possibly made a mistake and need to run test again. In case you have any interest, maybe run the test yourself for 1 week.
(Metal button + adapter + 20mm lighted switch) kit for for M21A M21B M21C M26C L21A S12 S16 etc.
When the battery is fully charged and the voltage is 4.2V
Blue light consumption current 9.4mA,
Orange light consumption current 14mA,
When the battery is low and the voltage is 3.0V
Blue light consumption current 2.74mA,
Orange light consumption current 6.8mA,
The new Sofirn numbers you just posted seem very reasonable. It is helpful to reference this mAh loss versus voltage drop plot of a Sofirn 21700, taken from HKJ's review.
I do agree that the voltage drop is highly nonlinear, but even with the flat top of the curve, losing 1380mAh would easily sink 0.2V, which is way off from 0.067V!
Ok, I think I understand my confusion now--the current draw from post #100 are Simon's numbers, not yours! I would love to see what kind of numbers you get with your test equipment. My meter only has 1mA precision, which is as good as none at this scale!
My numbers certainly disagree greatly from Simon's, but I couldn't say for sure that his are wrong for all lights. My setup is S2+ running 4-mode 5A driver, and it is known that driver choice greatly influences current draw. With a 17mm ramping driver instead, the drain is so low that my meter cannot register it at all, and the tailcap becomes much, much dimmer. Maybe there is some driver that causes faster drain, but I don't know. I feel that Simon is really erring on the side of caution with his numbers, which I do appreciate. It's better to expect hazardously high levels of current drain and get low drain in reality, than the other way around.
Finally did the measurement with this end switch arrangement and didn’t blow up anything (the end switch thing is the only reason why I haven’t measured it). 4 volt Sofirn battery with both S21D and M21B, blue metal switch. I have one lead on spring, other lead on battery rear, then press really (really) hard of end of cap to body of light for the blue light to go on. I hope that’s correct.
I think I found an explanation for why my empirical voltage drop is so low: the Convoy blue metal switch’s current draw is very low. So low that I have to have my wife take a picture for proof . Anyone with similar light if you’re interested please check to confirm my results.
Assuming I have done test correctly (I think so), the blue light metal switch in M21B and S21D is a miser, running about 400-500 µA, still higher than Anduril Dim (~100 µA), but nowhere near specs posted on Aliexpress of 9.4 mA. 9.4 mA is very bad and this error puzzles me - has anyone discussed this?
Thank you so much cannga for the data! Your testing method looks right, and the numbers are believable. 395 microamps over 3 weeks is 100mAh, which should result in less than 0.05V drop. The fact that you measured more voltage drop suggests that the loss from lighted tail is on the same order of magnitude as loss from self-discharge, which is really good news!
As far as I know nobody has discussed the discrepancy between Convoy's numbers and the actual current draw. Maybe we could make a post in the Convoy thread about this discovery?
Hi, this is my comparative:
WB at 5000K and on a 18% gray cardboard background.
1) Sofirn SP40 LH351D 4000K Hi-CRI
2) Wurkkos TS21 219C 5000k Hi-CRI
3) Convoy S2+ 519A 4500k Hi-CRI
4) Sofirn C8L XHP50D HI 6500k
White background, WB 5000K, from left to right:
1) Sofirn SP40 LH351D 4000K Hi-CRI
2) Wurkkos TS21 219C 5000k Hi-CRI
3) Convoy S2+ 519A 4500k Hi-CRI
4) Sofirn C8L XHP50D HI 6500k
shots between S2 + 100% and then TS21 on High (non turbo)
Both with this setup:
26mm f1.6
iso5000
1 / 15s
WB 5000k
Thanks. At the least Simon’s 9.4 mA is way off no? 9.4mA x 7 x 24 = 1579 mAh per week - is my math correct?
Most definitely my Convoys don’t go into LVP mode for at least a couple of months, let alone 3-4 weeks.
That 9.4 mA spec is actually the reason I included Convoy in this comparsion - it has bothered me.
Yeah perhaps I should ask him to clarify.
Hello Argo, I was reading one of your reviews the other day and could EASILY tell you are a seasoned shutterbug and pixel peeper (like me ). That was the first time I noticed that with any flashlight reviewers.
Thanks for the very nice photo comparison.
Hello Cannga,
thank you for your shots and for your topic, very useful.
Your math is correct, and I'm inclined to believe that Simon's numbers are way off. The only conceivable reason the numbers might possibly be right is that there might be some driver/switch combination that drives the tailcap really hard, perhaps to counter light loss from a metal switch (as opposed to silicone). But I don't see any evidence that such a combination exists.
I think it is a good idea to ask for a clarification. 9.4mA looks really bad, it's more current than the 0.1% mode on his 5A driver, which consumes 8mA at full battery.
Simon re-confirmed it is 9.4 mA. But check this very interesting discussion :
I vaguely remember trying to measure the lighted tailcap current years ago by hooking it up directly to the battery, without the rest of the light, because it is awkward to perform the measurement with the battery still in the light. I noticed that the tailcap was way brighter than it was while on the flashlight, and immediately stopped the test for fear of burning it out. I think I did get a number around 10mA. I think the driver does perform a role in reducing the current that goes to the tailcap LEDs.
Also, I have an S2+ tailcap from 2018 (not bought from Simon), and upon disassembling it I noticed that the epoxy casing on the SMD blue LEDs has turned a bit yellow, presumably from 6 years of having blue light continuously shined on it. It is also noticeably dimmer than a brand-new lighted switch on the same light/driver combo. I couldn't tell if the loss of brightness is from absorption by the yellowed casing, or if the LEDs themselves have degraded. I mean, 6 years is 52000+ hours, which surpasses the rated lifetime of some LEDs.
EDIT: I mean 4 years (35000hrs) from 2018 to 2022, not 6...maybe I should consider dropping my math major...
I just received my Wurkkos TS21 today. So far, I’m loving the light. The only issue I have is that when set to turbo the light seems to step down rather quickly. And by quickly, I mean it steps down after about 30 seconds or so. The thermal limit seems to be too low. I tried to raise the thermal step down temp. But, It is still stepping down way too quickly. Either, I’m doing it wrong, or something else is not correct. Can anyone advise me on how exactly to set the thermal step down higher? This is how I tried to set the thermal step down. I clicked 3 times from off, to give me a battery check. 2C for a temp check. 7H release after the first flash. I set the current temp to 1. After that, 7H released after 2 flashes. And then I clicked 40 times. So, 40 celsius plus 30 celsius equals 158F. But, the flashlight still steps down after about 30 seconds or so. I try setting it to 25 clicks. But it is still stepping down way too early for my liking. I measured the temps on the head and body. And it is stepping down at around 106 degrees on the head, and about 96/98 on the body. It feels slightly warm to the touch. Any ideas about what am I doing wrong?
Sounds like you did the setting correctly. And yes even at 40 click (70° C) the Wurkkos still steps down fairly rapidly, to about half brightness after 30 seconds.
A few suggestions - let’s retry 30 clicks (Tmax = 60° C):
1. Repeat Tmax setting: after second flash, 30 clicks. (After your 30 clicks, just let go and don’t click again right?) Afterwards let light cool (don’t use it) for a few minutes, then recheck temp of light. It should still read room temp around 21 C. If it reads around 30 C, you probably have made a mistake and set temp, instead of Tmax.
2. Now the checking: Turn on light at Turbo level and leave it there for about 10 minutes. At 10 minute mark check at head of light, it should read about 50 C.
3. Now turn light off and immediately (very quickly) 3 clicks then 2 clicks to check temp. It should read about 55-58° C. It decreases rapidly so you need to check it very quickly.
In general and roughly, I’ve found
a. external temp (with the IR gun) at the head reads about 10 degrees below Tmax
b. internal temp check reads about 3-6 degrees below Tmax, but you have to check very quickly right after.
Another example, if you have set Tmax to 70° C correctly, external temp should read about 60° C, and internal temp should read about 65° C. Hope this helps.
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