That’s your opinion. My opinion is it’s not reasonable to expect a light to run in a manner it was not designed for.
And if stepdowns make a light “cheap” then the TX25C2, Zebralight SC600 Mk II, TN31 and a host of others are “cheap.”
The stepdowns aren’t a secret and if someone doesn’t like them they shouldn’t buy the light or buy it and mod it.
Besides, (and correct me if I’m wrong) nobody here’s demonstrated the EA4 will fail by repeatedly switching it back to turbo.
Exactly.
To satisfy those few who actually read the manual and the even fewer who choose to obey it, the EA4W light output sags by 14.7% withing the three minute turbo operation.
My modded HD2010 sagged 5.7% after three minutes.
I think I’ll add another light to compare, something stock. Maybe the Convoy M1 and/or the Convoy C8… pretty much all I have left in stock form, actually 
So the conclusion seems to be that the EA4 (and by inference the EA8) have "adequate" heatsinking. Well, adequate enough to prevent undue thermal sag once the thermal "pressure" inside builds up high enough.
The problem is we can't know what temperature these lights are reaching inside the head and driver cavity for this equilibrium to be reached. All logic would tell us that it would be much higher with a poor thermal path than it would be with a well-executed one.
OK, maybe the emitter won't turn blue but this has to be stressing the driver components sitting underneath in that little plastic sweat-box.
The lights may not fail during an extended runtime test but my (admittedly uneducated) gut feeling is that these are not going to be long-lived lights. That much heat has to eventually short-term some component in there and we have clearly seen from OL's teardown that when it happens it will be extremely difficult to fix.
Like some others in here, I still feel this is a poor effort on Nitecore's part when to do it properly surely couldn't have cost them that much more.
Planned obsolecence perhaps?
I second the Convoy M1, i can also provide a second Convoy M1 for comparison
+1 for Convoy M1. I have one too. 
Huh? I don’t see any problem within 30 seconds and the EA4 actually sags less than 2% before it steps down at 3 minutes.
You compared it to an HD2010 so here’s the normalized relative sag of the EA4 compared to four 18650 lights and it sags less than all of them. I don’t see what the problem is.
There is an obvious disparity between my data and that data. I am at a loss to explain why, or be able to point out which is incorrect. One must be incorrect, or the light used in that test is far superior in thermal transfer properties than mine.
Anyway, once I have my tests complete, I’m starting a new test results thread, as this is drifting away from the original EA8 tear-down purpose of this thread.
I do have a question.
1. How close to initial turn on is the very first output sample taken?
In my case, I’m measuring lumens via a home-made light box (easily good enough for relative measurements). The initial output sample is captured with the light meter set to MAX hold before I turn the light on. A few seconds after I turn the light on there’s no chance of a higher value coming in, so I record the max that was captured. This ensures I get actual max output right when the light first turns on.
A question I would consider is how accurate is a light meter when suddenly flooded with light initially. I have my own meter and mounting a flashlight and turning it on max gives me initial starting values that range from 80,000 to 85,000 under the same circumstances. After the flashlight has warmed up I run the initial test again and get a range of anywhere between 79,000 to 84,000.
That is a good question. I have the light meter preset to the range that I expect the light level to be in (in this case x10 mode up to 20kLux). It is not using the Auto-Range mode.
Still, I cannot say with any certainty that the meter is OK with a sudden flood of light. I would hope it is OK with it. If it is not, then there is no way to capture the initial output of an emitter. Waiting a second or two is too late. The largest drop is in the first two or three seconds.
Do you get the same effect when you try a different light, i haven’t seen any testing on how long it takes an LED to go back to full brightness after cutting then reapplying the power
Are you using the same cells in the test? Their voltage will be lower since some capacity has been drained from them in the initial run.
Not going anywhere, but in retrospect and after reading other threads and seeing other results, I do think that under “Normal use”, the light would never be an issue for anyone. It is not the way I would want it and I still don’t like it, but I just feel I jumped the gun without having more info. The EA8 is a well made light. One of the best made I have seen…, until you open it up and see what is behind the loctite. Well, the average guy would never see, never know and the average guy would never use turbo. I don’t even see a reason for turbo. I have used the light and the difference between turbo and high is not worth messing with, so overall, the light works as intended. I don’t think it’s worth the money, but I never think that, even with lights I have made.
My mom always called me to the Kitchen whenever she needed someone to "stir the pot".
I thought of this a little while ago when I plotted the Convoy C8 data. If it was the meter being swamped somehow, then the actual light being used should not matter. However, in my data the initial sag is only being recorded on certain lights (in my tests, the EA4W and the M1). My thread will be posted shortly with the results.
Quick preview for those interested; M1 has sag issues, C8 is rockin’ it.
tickle me pink, i would not have expected sag issues on the M1
I should have said that relative outputs were in throw on that first graph. Here’s the same thing in lux which makes the percentages larger but the overall picture is the same.
I’m using an Extech SDL400 which I set to record every two seconds and which auto-ranges. Each light began at room temperature and I’d start recording in the dark and turn the light on. Since the meter’s already running, initial readings were recorded somewhere within in a two second window. But so what? IMO initial “actual max” is irrelevant compared to three minutes of output.
Big time sag issues. As can be seen in the above graph and longer term here:
As cheap saggy lights go, the M1 actually does not sag too bad… It’s basically just not regulated.
You are potentially missing the most important period of lumen sag; the first two seconds. IMO, ignoring this is unfortunate and invalidates your data. The variability in your readings alone causes problems. What if the M1 happened to get sampled right when it turned on, but the EA4 happened to get sampled right around the two second mark? On the EA4, the difference from time zero to the two second mark for me was about 45lm. This does not totally explain how your data shows about 4% sag during the first three minutes and mine shows almost 15% sag during the same time period. Something is still amiss. Did I read somewhere that you also applied forced air to the light under test?
Even my sample rate is limited by the meter; it is documented at 400 milliseconds in the manual.
Agreed, the M1 is not as bad as some. I still need to investigate what’s going on, I think the star contact may be limited.
For those interested, my thermal testing post is up, here with more lights tested. Future test results will be added to that thread.