+1
Problem is the max sustained output varies by emitter and ambient temp, so there isn’t a fixed % for sustained brightness. Also keep in mind that 35% is current, and the lumens at this level is more like 50% due to increased efficiency at lower currents.
Good point regarding the 35% current being >35% output. For the rest, I was mostly thinking a ballpark figure of “ok, at 50C, the S2+ can dissipate about X amps of waste heat, while the C8+ can dissipate Y, so let’s pick a # between the two.” Then divide by the efficiency of the most popular emitter. Repeat for the S21a and one of the M21 series.
Just a rough compromise between not underpowering the large lights, while avoiding a big thermal stepdown in the small ones for a given driver.
Simon, I just read ZeroAir’s great review on the L8. I think I’ll have to buy one. 
But I noticed that the spring is now a thicker 1.5mm. I measure my old M3 and M3C at 0.9mm. This is a great change, thank you. Can we buy these new springs from you separately?
Waiting eagerly to see a demo of GT FC40 1800-2000k on full blast…
Anyone got one on the way?
Sorry, I don’t have the relevant reflector and driver.
毛裤 ,That’s my real Chinese nickname 
and 4th config menu option ——> strobe active or not.
how about this?
I don’t have extra springs, I can source some from the factory if you need them. However, the elasticity of this spring is very poor. If you don’t calculate the size, it will most likely deform your battery.
My thought was to put them into the M3 and M3C as replacements because they are stiffer. Would that work? Using the same QB 26800 cells with your adapters.
This would be a great change.
The L8 uses a 1.5mm diameter spring because its current is as high as 25A.
The maximum current of the M3 M3-C is only 10A, so it is not necessary to use such a thick spring.
Not thinking about current, just about the past discussions in this thread about the spring being too weak in the M3 lights - they will turn off or cut out/blink when bumped softly. The 26650 and 26800 cells seem to be too heavy for the single tail spring but we thought a stiffer one would be a good solution (that or two springs in the light instead of the brass post on the driver). The spacer boards don’t fix that problem even with 2 or 3 of them (too much). So far the best solution has been to add an old P60 drop in spring (just sits on top of the retaining ring loosely, in addition to the stock spring…sort of works). One guy used a short piece of rubber hose as a cushion inside the stock spring. So I was hoping this new thicker spring might be the answer for the M3/M3C.
This is because the battery tube in the middle of the flashlight is too long.
you can solder a spring on the spacer board
As long as strobe mode with mode memory is still possible, and it is a 10Hz strobe.
Sadly too many flashlights now have hidden, and alternating frequency strobes.
On these newer designs with only one side having a spring, the slightest shock load interrupts current flow. Traditional springs on both sides allowed cells to bounce back and forth without loss of contact. Traditional double ended springs also kept the positive side of the battery from hard impacts into the bottom of the circuit board. If that brass contact stud is denting batteries on impacts how far away is board damage. Granted newer boards have little space left of springs. These impact interruptions on current cause mode changes, or lights to go off. The more important the lights use the more critical an issue this becomes. When I did traffic control just waving some of the newer lights made them unusable from constant mode changing. A dropped light can be picked up, a dropped light that just turned itself off has to be found.
It’s very annoying. Was thinking of the FC40 1800K as a nightlight. But this is a no go for tail buttons flashlights. You turn it on, switch to the level you want and put it down. And it switches level! Have a M21B and S11 and both are not suitable for tailstanding because of this. The M21B is not too bad, but the S11 is unusable for this purpose. Which is a shame, because the thicker S11 makes it more stable. Don’t get me wrong, they are nice lights, just not for tailstanding. I’m putting my hopes on the upcoming side switch lights.
Thank you for posting that 1800-2000K measurement Simon. Looks good and I’m really looking forward to it. Also, the colour temperature in that measurement is my birth year. A must buy
Yup, in a M21B. But it’ll take a while to arrive.
I think that would be excellent as well! If all the blinky modes including strobe could be enabled or disabled, you could remove several of the duplicate mode groups as well. I think that would be a significant improvement!