GT FC40 vs 519A vs B35AM ???

I have B35AM in a couple weeks and will compare throw against GT-FC40 in same host, M21B.

Another choice as mentioned by phantom23 is M21E. It is noticeably more throwy than M21B. I don’t have the numbers with me but roughly IIRC it’s about 280m for M21B and 330m M21E. (Please don’t quote me on this; I measured all 3 but somehow completely forgot to post in my other thread.)

I too much prefer “smallish” lights. I have M21B, F, and E all with GT-FC40 4500k. E is noticeably most throwy, and the larger head is not too cumbersome. I use it most often because I like to see further ahead in my evening walk. And I tend to like throwy light.

B has dimmest hotspot but brightest spill (most floody)
E has brightest hotspot and dimmest spill (most throwy).
F is in between, but leans more towards B.

This LED doesn’t seem to burn up everything in sight like SBT90.2 :person_facepalming: :slight_smile: . Thermal mass always helps but IMHO not that critical, at least among these 3 lights. Sustained brightness from Turbo run is around 37% of max, the smaller M21B just steps down a bit sooner. None of the 3 lights becomes excessively hot as with smaller lights. Hope this helps.

Effect of size on runtime brightness M21F versus E, using ceiling bounce percentage.

All 3 M21B, E, F settle around 37%. My conclusion IMHO: The difference between B, E, F is not so much sustained brightness but more the character of the beam (hotspot vs spill).

BTW the left-most blue curve that looks like it’s falling off a cliff :slight_smile: is S21D with 12A FET driver.

What batteries do you use? I guess a samsung 50e would not have a high enough continuous discharge rating?

One good thing about the L6 is it has pretty decent battery capacity since you can choose the Shockli 26650 IMR 5500mAh or use tube extenders to put in 26800 batteries. Not sure how real world run-times would compare but I assume the L6 would win.

Edit: I guess vapcell has 26650 cells that are nominally 6200mah but with a ctd. I guess depending on the light those would be a superior choice for capacity

I have tested Samsung 40T against Wurkkos, Littokala, and Sofirn etc. in my FC40 lights and also the Wurkkos TS30S with monster LED SBT90.2.

In the Wurkkos light, Samsung 40T registers a shocking 15% gain for Turbo turn-on brightness, using ceiling bounce. I repeated the test multiple times because I couldn’t believe it, but 15% it was. Wurkkos TS30S + monster LED SBT90.2 = $60 4750lm 1km SUPER-Thrower. Comparison w/ TS30S Pro & other lights incl. the :-) insane 13000 lm Nightwatch Valkyrie. (Summary & measurements on P. 1) - #74 by cannga

In the GT-FC40 lights, Samsung 40T makes no brightness difference vs other less capable batteries. Assuming the spring or something else is not the limiting factor, my thought is that FC40 LED is not that current hungry enough for these batteries to make a difference. But this is just amateur level test; I have not measured the actual current draw.

Yeah, the Vapcell K62 are what I use in the L6. I do have 6800 mAh 26800 cells, but honestly the difference in runtime between 12400 mAh and 13600 mAh is not very much in real world usage, and I like the size, weight, and balance of the L6 exactly how they are.

I have QB26800 cells in my L7 (SBT 90.2). For that host I feel that it actually improves the balance but I haven’t tried them in the L6. Which 26800s do you have? I have heard that the yellow Queen Battery 26800s test at 7100mah but haven’t tested mine.

I was thinking of either the b35am or the gt fc40 in a D1V2 - but I came across this thread

Is the flux binning on the gt fc 40 really that inconsistent?

Can’t speak for Emisar but I have 4 Convoys all w/ FC40 4500k and some quick readings this morning with the TA lumen tube - highest values:

M21B 2250 lm
M21F #1 2150 lm
M21F #2 2220 lm
M21E 2140 lm

I also have the Nichia BAM in Convoy M21B. IMHO, the BAM is low heat low output (~1000 lm) at 2.4v so small host is ok. FC40 is high output high heat, at least in Convoy, so if possible I would prefer a larger host for less step-down if you tend to use your light at high output.

Appreciate you taking the time to get that data for us

For the same CCT, is there any significant tint difference?

No - just a VERY beautiful beam color, among the most pleasant to the eyes. One of my two M21F’s has a more magenta hotspot in white wall hunting but not easily noticeable in actual use. If rosiness is on one end and warm golden tone on the other, then IMHO I would place FC40 in this order:
ROSINESS tint 219b 4500k>BAM 4500k>FC40 4500k>519a 4500k GOLDEN tint

The rosiness/magenta tint of 219b sometimes could be a bit much (even though it does make colors pop the most), and FC40 is a step away from that toward 519a, in a pleasant in-between spot. Completely personal preference but I would say less stressfull maybe, and especially so IF you don’t like rosy/magenta tint.

You won’t regret any of the above 4 LEDs, they are all excellent for different reasons, and you most definitely won’t regret FC40 4500k. It’s the light I use the most among all my lights (even though I am somewhat of Nichia die-hard) because it provides all 3 important qualities in balance: beam color quality, brightness, and throw.

Here’s a beamshot to show what I describe above:

Picture shot in manual mode w/ Canon DSLR, WB fixed at 5000k

Thanks for the comparison pics. I think I need some fc40 in my life

I should add my comment about the wonderful beam color applies only to the 4500k CCT version of FC40. The “5000k-5500k” FC40 which I also have has a colder more daylight look as expected (measured CCT 5300k, Duv 0.0004). It is good but not the one I would recommend first.

Re. output my 5300k FC40 measures 2220 lm with TA lumen tube. So all 5 FC40 lights I have are in that ~2200 lm range.

For comparison purpose, pls note all my brightness measurements are at turn-on, not 30 seconds as I’ve seen in some reviews. All are done with Samsung 40T batteries, which tend to result in a little higher output than the Littokala that Simon has for example, in my limited experience. Hope this helps.

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No sorry I don’t have TS10. I would like to clarify that there is absolutely nothing “wrong” with the FC40 5500k. In fact it might be among the “best” 5500k LED color wise, and it has equally great Ra and R9 as its 4500k brother (that’s why I bought it).

It’s just that the FC40 4500k is my personal favorite by far, and it has a nice warm beam color that looks like a LED that’s in between 2 outstanding LED’s: 219b 4500k and 519a 4500k.

If you like a colder (more blue) beam color then sure, FC40 5500k is the one to buy. I have some beamshots comparing SST40 6000k, FC40 5500k, and FC40 4500k I could post later.


Measurements from Simon:
GT-FC40 4500k
CCT 4521k
Ra 93.2
R9 76
R12 70

GT-FC40 5500k
CCT 5598
Ra 93.6
R9 78
R12 73

I have to agree, that 4500k FC40 is very nice indeed.

Funny someone mentioned that. I measured my M21B FC40 5000-5500K yesterday, and the CCT was 5809K. A fair bit colder than it should be. I always thought it looked too blue, and the measurement confirms it.

General question for all…

In M21B, 519a vs GT FC40.

519a would output less lumens and have a more throwy beam than the GT, with more lumens and more floody beam.

My question: which one would actually throw further.

If both are driven to their absolute max, the throw is comparable. If the 519A is dedomed, it throws farther.

At the same power input, the 519A handily beats FC40 in throw.

I personally much prefer 4500k, but I bought FC40 5500k to see what it looks like as it has probably among the highest Ra and R9 for a 5500k LED.

I took these pictures to show progression of CCT and “blue.” The red bougainvillea on left side looks almost violet with the SFT40 6000k LED.



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