surefire stiletto pro 2

dddrees

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No, you don't understand. One of the annoying industry practices out there (aside from most brands reporting over-inflated emitter lumens numbers, as opposed to realistic Out The front numbers which are always considerably less than emitter numbers) is the practice of over inflating runtimes. Highest setting on a flashlight, you are not getting continuous output on that setting for the whole 1.5 or 2 hours, or 3 hours. No. Unless that "high" setting is a very low number. You might get continuous output for hours if your light is producing 30 lumens or so on its high setting. But 500 or 1,000 lumens for anything remotely close to an hour? No! LED technology is not to that point.... yet.

Those over-inflated runtimes mean that the light starts off at a very high setting. Lasts for a few minutes, then during that 1.5 or 2 hours; you'll see the light drop significantly in output. Oh! But since the output you're now getting is still useable for most lighting tasks, the various brands count that decreased output as if the light is still going just as strong as it was from the very start! Yeah, that B.S. continues after more drops in output. And only ends when the output is so pathetic that not even the various brands themselves can pretend you're getting a useful amount of light out of your flashlight.

They don't stop counting runtime the very first time output drops off a cliff when your light is in Turbo or High mode. Even though they should.
I get it.

Anyway I ran another test just now since I just charged it last night. This time I clicked it on high and just let it run. So although I kept an eye on it auto reduced the intensity of light at some point after 50 minutes and after it started blinking red and I let it continue to run. At a little after 59 minutes I shut it off and turned it back on high. It auto reduced the light shortly after and then shut down. So tonight it ran for 60 minutes but at some point after 50 minutes and after it started blinking red it no longer ran on high.

I am still fairly confident I didn't pick it up and turn it on after I charged it before I ran my first test. So I'm thinking that period where it sat the battery's must have drained a bit between charge and testing. That or there is something different when running a light multiple times instead of just once in regards to how much power is used..
 
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Bob A

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No, you don't understand. One of the annoying industry practices out there (aside from most brands reporting over-inflated emitter lumens numbers, as opposed to realistic Out The front numbers which are always considerably less than emitter numbers) is the practice of over inflating runtimes. Highest setting on a flashlight, you are not getting continuous output on that setting for the whole 1.5 or 2 hours, or 3 hours. No. Unless that "high" setting is a very low number. You might get continuous output for hours if your light is producing 30 lumens or so on its high setting. But 500 or 1,000 lumens for anything remotely close to an hour? No! LED technology is not to that point.... yet.

Those over-inflated runtimes mean that the light starts off at a very high setting. Lasts for a few minutes, then during that 1.5 or 2 hours; you'll see the light drop significantly in output. Oh! But since the output you're now getting is still useable for most lighting tasks, the various brands count that decreased output as if the light is still going just as strong as it was from the very start! Yeah, that B.S. continues after more drops in output. And only ends when the output is so pathetic that not even the various brands themselves can pretend you're getting a useful amount of light out of your flashlight.

They don't stop counting runtime the very first time output drops off a cliff when your light is in Turbo or High mode. Even though they should.
I've seen the runtime graphs, but they don't answer my basic question:

Does the same discharge curve apply every time you use the light, or does the max output decrease after first use, so you effectively start from a lower output?

At what point in the diminishing power reserve of the battery does this affect the initial output (of course I'm thinking of the highest setting with this question)? 80%? 50%? Or right after first use?

I'd assume that the final curve after a number of uses would of course drop off in ultimate duration, since I assume the graphed figures are based on a single operation of the light, and measured until failure. Is this correct? What other parameters might be affected as one cycles the light over a period of time?

Thanks for your insights.
 

Monocrom

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Does the same discharge curve apply every time you use the light, or does the max output decrease after first use, so you effectively start from a lower output?
Not every time. If you use a light with a fully charged up battery on its highest setting for only a few seconds, then immediately switch it off and wait; Yes, you will get maximum output the next time you switch it on. But, if the battery isn't fully charged and it kicks the output level down after you've used it. One of two things will happen after you switch the light off, and then on again in its highest setting. Either it will turn on, in that setting but will immediately kick down to a lower setting. Or, it will not switch on at all on the highest setting. It'll switch on in a lower setting until the battery is recharged.
At what point in the diminishing power reserve of the battery does this affect the initial output (of course I'm thinking of the highest setting with this question)? 80%? 50%? Or right after first use?
Honestly that variable depends on the specific flashlight model, and what its highest setting happens to be. Some lights will hold that highest setting as long as possible, but then output will noticeable drop off significantly. (As if the output wasn't watching where it was going and fell off a giant cliff.) That's what you can expect on most modern-day LED lights. The alternative is a flashlight that will start off on the highest setting with fresh batteries. But the longer you use it, it will start to almost immediately very gradually dim over the time you're using it. So much so that at first it won't be immediately noticeable. That gradual dimming will continue until your light is barely producing any output at all. But, there's no drop off from a cliff. Picture a very gradual slope heading down.
I'd assume that the final curve after a number of uses would of course drop off in ultimate duration, since I assume the graphed figures are based on a single operation of the light, and measured until failure. Is this correct?
Yes. Single operation. Start to finish. Multiple operations aren't used.
What other parameters might be affected as one cycles the light over a period of time?

Thanks for your insights.
Temperature extremes can definitely have an effect on how flashlights will perform outdoors.

Happy to help.
 

umc

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Here are a couple comparison charts I found on one of the recent YouTube videos
 

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aznsx

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I've seen the runtime graphs, but they don't answer my basic question:

Does the same discharge curve apply every time you use the light, or does the max output decrease after first use, so you effectively start from a lower output?

At what point in the diminishing power reserve of the battery does this affect the initial output (of course I'm thinking of the highest setting with this question)? 80%? 50%? Or right after first use?

I'd assume that the final curve after a number of uses would of course drop off in ultimate duration, since I assume the graphed figures are based on a single operation of the light, and measured until failure. Is this correct? What other parameters might be affected as one cycles the light over a period of time?

Thanks for your insights.
Honestly that variable depends on the specific flashlight model, and what its highest setting happens to be. Some lights will hold that highest setting as long as possible, but then output will noticeable drop off significantly. (As if the output wasn't watching where it was going and fell off a giant cliff.) That's what you can expect on most modern-day LED lights.

The alternative is a flashlight that will start off on the highest setting with fresh batteries. But the longer you use it, it will start to almost immediately very gradually dim over the time you're using it. So much so that at first it won't be immediately noticeable. That gradual dimming will continue until your light is barely producing any output at all. But, there's no drop off from a cliff. Picture a very gradual slope heading down.



I'll just add another .02 to what @Monocrom has already provided. There are many variations on output control algorithms used. Here's a couple of examples of the types of operation which I personally prefer:

My current 'favorite' light works like this. In this case, it starts at max rated output, then the output is fairly consistent for the majority (~80%) of the rated run time, then ramps down (with one 'knee' in the curve) following that to ~55% (which is its rated run time point), then drops more rapidly as the cell becomes largely discharged:

Screen Shot 2024-03-25 at 3.04.42 PM.png


...and the next light I'm considering purchasing works like this. It starts at max rated output, then almost immediately begins a very gradual (fairly imperceptible) ramp down to just under 70% of that max output (during the initial 20-30 min.), and maintains that flat line out to ~85% of total rated run time, before the cell is largely discharged and then decreases fairly rapidly during the last 15 min. of its FL1 rated run time (to 10% of max)

Screen Shot 2024-02-15 at 1.03.37 PM.png



Does the same discharge curve apply every time you use the light, or does the max output decrease after first use, so you effectively start from a lower output?

In most cases I'm familiar with, lights will execute their designed output algorithm after power-on at max rated output each time the light is powered 'on' from 'off'. Up to a point, the only real change as the cell becomes more discharged, as you speculated, is the overall duration of the main part of the discharge curve. With repeated operations, there will be a point of cell discharge at which the cell cannot sustain the max level for long, so that initial portion of the algorithm will be progressively shortened, but the primary effect is on the 'majority' portion of the output curve, and less so the first part. Eventually, when the cell SOC (state of charge) becomes very low, obviously there's a point where the light will be unable to operate at max output at all, and may only be able to sustain lower output levels. Then of course, there's 'death';-). Your questions are all valid, however it's difficult to put meaningful 'average' numbers on those things, because they vary widely with different designs. There are simply too many variables to generalize in a meaningful way. To provide / document all those data points for a given specific light would require more extensive testing beyond the scope of what is commonly done. What you would ideally want to see is an output / time graph which also graphs cell voltage, then one could interpolate a bit and extract more useful info by using that cell voltage level (or essentially, SOC).

At what point in the diminishing power reserve of the battery does this affect the initial output (of course I'm thinking of the highest setting with this question)? 80%? 50%? Or right after first use?
This occurs at a relatively low SOC (I'm thinking way under 50% - probably more like 20-30%), but it's hard to put a meaningful average number on that. Too many variables to generalize (although not that difficult to measure / document for a specific light using fairly basic equipment). EDIT: I may be underestimating this number, and it could be 50% (SOC) or more. Others with more experience w/ flashlight drivers could provide a better general number to use than I can. In lieu of better data, I think I'll assume 50% as a working assumption.

I'd assume that the final curve after a number of uses would of course drop off in ultimate duration, since I assume the graphed figures are based on a single operation of the light, and measured until failure. Is this correct? What other parameters might be affected as one cycles the light over a period of time?
That's correct. Output / time is typically graphed for a single, sustained operation. I'm not aware of impact to other parameters besides output power (lumens) and run time (lumen-hours, if you will), but clearly as output decreases, so does 'intensity' (CD), so there's that.

You may not find answers to all the questions one might possibly ask, but the primary point here is to, at minimum, try to deal with manufacturers who at least provide a basic output / time graph with their product specs. That is the minimum, starting point for understanding how a given light will actually perform. Many do not even provide that basic info, and since it's not very difficult to obtain with fairly nominal equipment required, you should ask yourself: "Why?" Even if you can't get all your questions answered, at least try to insist on the basic performance info, as above. If the manufacturer chooses not to publish that info (for whatever reason?), then they leave you dependent on the aftermarket / 3rd party testers / reviewers to provide what they don't wish to provide you with.

What does the basic output / time graph look like for the light this thread is about? I'm completely unfamiliar with this light, and am only addressing these things in broad, general terms. I guess it's possible that nothing I've said applies to this light at all:).
 
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aznsx

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This occurs at a relatively low SOC (I'm thinking way under 50% - probably more like 20-30%), but it's hard to put a meaningful average number on that. Too many variables to generalize (although not that difficult to measure / document for a specific light using fairly basic equipment). EDIT: I may be underestimating this number, and it could be 50% (SOC) or more. Others with more experience w/ flashlight drivers could provide a better general number to use than I can. In lieu of better data, I think I'll assume 50% as a working assumption.
^^^^^
Edit. Anyone else have a good general 'ballpark' number to use for this?
 

umc

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So Surefire got back to me after testing and said that the battery is fine and that there is no reduction in overall run time compared to other pro II's they tested against. They said the battery indicator LED programming is not ideal and they're looking into changing the way it is displayed.

So they're shipping a light back to me. I don't love that I'll have an LED I don't trust but I'm excited to get the light back and use the crap out of it.
 

dano

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Received mine, recently, and so far, the runtime has been horrible. But reading this thread, it's probably normal, though constant on--going from green to orange to red in a few minutes of each other is a bit perplexing, and if the battery isnt dumping voltage, then the battery indicator programming is really inaccurate. Surefire has really been circling the drain, but lights seem to no longer be their main priority.
 

umc

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Received mine, recently, and so far, the runtime has been horrible. But reading this thread, it's probably normal, though constant on--going from green to orange to red in a few minutes of each other is a bit perplexing, and if the battery isnt dumping voltage, then the battery indicator programming is really inaccurate. Surefire has really been circling the drain, but lights seem to no longer be their main priority.
Yeah according to Surefire the battery indicator programming is an issue. I'm hoping to get mine back this week and to just use it and see how it goes.
 

umc

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Must be selling well…. Already out of stock at B&H.
Oh they are, the service department sent me an email said they were trying to find me a replacement because they were back ordered which pissed me off because I specifically asked if they could just send me a replacement first, they said no but they would once they had mine, that still didn't happen so now the delay. oh well. I bought mine from Midway USA and checked back with them and they were out of stock so I'm sure they sold out quick.
 

Monocrom

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It's new, it's SureFire, it was heavily promoted at SHOT show.... Sadly it seems you were one of numerous unpaid Beta-testers for this model.
 

umc

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It's new, it's SureFire, it was heavily promoted at SHOT show.... Sadly it seems you were one of numerous unpaid Beta-testers for this model.
Yeah I hear that. I figured the original and pro were well liked so I figured this wouldn't be much different. I'm looking forward to getting it back and just using it and seeing how it does for an edc.
 
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