I think initial testing temperature is very important. You must let your flashlight get cold before starting doing test. Maybe let your flashlight sit there for 2 hours before starting test. Else sagging percentage might not be accurate.
Hi OL. I dont think anyone is listening to you anymore. There all on there own mission now. I’ll see you back at the build thread. 
Yep, that’s exactly what I was going to say.
Surely any sag in the first two seconds couldn’t be due to poor contact from the heatsink to the body, but must be due to the efficacy of heat extraction from the LED itself?
Why do you think the first two seconds are so important that they “invalidate” the following three minutes? I have five luxmeters and can easily capture the initial max but IMO it’s irrelevant and won’t bother unless someone gives me a good reason. Who cares about when in the two second window the sampling started? There’s no “variability” that “causes problems” as anyone can see by looking at the graphs. The curves are relatively smooth for three minutes with no spikes or drops. To claim that almost 100 data points on each of five lights are invalid because of the “reasons” you’ve given seems more to me like grasping at straws because you don’t like the results. And no, there was no forced air applied. What meter are you using BTW?
Why is sag in the first two seconds at all relevant? If someone gives me a good reason why it’s important, I can capture it and graph it for each of the five lights. But it seems to me that obsessing about it is pole vaulting over mouse turds and missing the bigger picture 
The output at zero seconds is the actual capability of the emitter. I care about that number. Having good heatsinking allows me to get closer to that number for longer.
That still doesn’t invalidate other baselines… and as Calvin pointed out, there’s the question of meter accuracy when initially flooded and based on how far off some of your lumens readings look in your thermal performance thread, I wouldn’t be so sure of your measurements.
You’re also misinterpreting the data based on some of your comments.
What luxmeter are you using BTW?
Isn't ANSI spec 30 seconds, to stabilize the light? I would think any readings before 30 seconds would be erratic and not viable. Isn't that why there is an ANSi spec? I know you are checking temps, but that should be erratic at first turn on too.
Yes, between 30 seconds and two minutes, great point. I was thinking the exact same thing which is why I made this graph of lux sag over the entire ANSI/NEMA FL1 testing window.
I’m not too concerned about the meter, as long as the same one is used for the entire time period. I’m looking for relative numbers only. I responded to Calvin’s comment; I guess you missed that. If it is the meter being swamped by the initial turn on, I would think 1100+ lumens from the HD2010 should have really messed with it; but my graph shows otherwise.
Clearly the initial sag doesn’t matter to you. ANSI cares about it. They do not want a manufacturer to test a light within that period and publish the result. Why? Well, because the initial sag on most lights is significant.
As I said, I only care about the initial output so I know what the potential of flashlight is. From there I can decide if some heat sink mods are required.
Clearly, you do not care about this and I’m happy to let you continue down that path.
I thought this was a EA8 thread….nice chart BUT where is the EA8? I think this belongs in a different thread unless you add the EA8 to the mix.
I already started another thread, linked in a previous comment. So far, not many questions like this over there. This is my last non-EA8 tear down post in this thread.
In case anyone runs into real Loctite, here's what the Mfg says;
red
It is only
removable once cured by heating up parts to 500°F (260°C).
blue
For disassembly, shear with standard hand tools and remove with methylene chloride. In rare instances where hand tools do not work because of excessive engagement length, apply localized heat to nut or bolt to approximately 482°F (250°C). Disassemble while hot.
green
For disassembly, shear with standard hand tools and remove with methylene chloride. In rare instances where hand tools do not work because of excessive engagement length, apply localized heat to nut or bolt to approximately 482°F (250°C). Disassemble while hot.
The red thread locker on the Nitecore is NOT Loctite brand, as it gave up before the Ano discolored. I imagine it's an overseas budget type locker.
My UF-T90 had some red crap on the tail threads and it broke free with no heat. Just a pair of thick rubber gloves and elbow grease. Definitely not Loctite.
I feel so blessed . . .
Of course you’re not concerned about your readings being wrong. You’ve shown you’re not interested in facts or reality if they conflict with your opinions. So keep obsessing about those first two seconds which, in the scheme of things, are irrelevant. It’s even irrelevant by your own data but you don’t know how to interpret it.
Do you even have a copy of ANSI/NEMA FL1? If so please tell me where it covers initial sag because all the measurement standards I see start at 30 seconds. Or do you think there’s a conspiracy between ANSI and manufacturers to “cover up” initial sag? 
Good luck figuring out “if some heat sink mods are required” when you don’t even understand your own data.
Luvlites, were your EA4 and TX25C2 not switched on for at least maybe 1 hour before the test? Look at the graph, looks like their sagging is not “natural” and might almost reach equilibrium of heat transfer in and out. I mean they look like they are already warm before your test, I suspect that is why they don’t sag as much comparing to others.
Both lights had been off for several hours and were room temperature. That graph does not include the first 30 seconds and is the normalized 30 second to two minute slice of a much longer test. If you want to discuss it in more detail, I’m happy to but it would be more appropriate to do so here where I posted those readings: Comparing Throw of the EagleTac TX25C2, Convoy M1, UltraFire UF-T50, & Zebralight SC600 Mk II
It is good to see measurement data from members, but let’s discuss it with objectives. Be cool.
My take is if the initial 0-30s max output is not used for advertisement by manufacturer, then when judging manufacturer’s flashlight sag over temperature, we should use 30s as reference point. It is because manufacturer is honest and follow ANSI standard. We have to be fair to honest manufacturer.
If a manufacturer use the 0-30s max output in their advertisement, then we don’t need to follow ANSI standard anymore since they try to cheat user with very good output number.
I know some modder just want to see thermal performance, and don’t care much about manufacturer being honest or not. But the test result might cause wrong interpretation about certain product. For example, if EA4 start out at 0s to be 1000 lumens, but Nitecore use 30s output which is 860 lumens for their spec, saying Nitecore EA4 sag a lot by percentage is not so fair. But if Nitecore use 1000 lumens as their advertised spec, then we can say EA4 sag a lot by percentage.