GT-FC40 1800k-2000k, less output?

Off-topic Chatter
1

I know that in some cases different temperature emitters of the same model have varying levels of output. Is this the case with the GT-FC40? I’m wondering if I’d sacrifice any output in choosing a 2000k emitter vs the 4500k or 5000k. If so, approximately how much output is lost?

2

Warmer means more phosphor on top, so yeah, output does drop somewhat.

A guess might be 20% less.

3

About 25%

4

Anyone got spec-sheets for the GTFO-40, just lookit the lm/W for each CT. Might be various “bins” as well, so an efficient 2000K might have the same efficiency vs a less-efficient 5000K.

5

Ah, I was close. :laughing:

6

Aw that’s unfortunate. Now I’m thinking a 2000k GT-FC40 in an L6 might be kind of silly—not a lot of output for such a large light.

Thanks for answering.

7

But you will see more far away with warm light. I recommend to try.

8

I don’t think Simon shared the flux bins of his FC-40, but you can use this as reference since that a similarly high CRI LED:

–37% from 5000K to 2000K (–35% at rated current = 0.7A)

9

I don’t think it’s silly. I want it in a KR1.

10

Yea but the KR1 is tiny compared to the Convoy L6. Personally if I have a big weighty light I expect better output to match. It’s true that throw and battery life would still be advantages, but I’m not sure if it’s enough for me personally.

11

Its true. Don’t trust the lumens numbers, cool white may look brighter, but only for blinding you, its easier to see objects and shade on a lower lumen warm white light. And usually also colors since they have better CRI.

12

I know that’s somewhat true from experience but there must be a point of diminishing returns. I’d think at 2000k you might lose too many lumens for the light temperature to offset. Maybe 3000k or 4000k are better choices for example.

13

Hank emailed me on FC-40 KR1

"FC-40 is more on the flood side, about 1800lm and 10kcd."

I assume he's talking about the 4000K tint (that we were emailing earlier, but he did not specified tint in this answer)
So like 95% he's talking about the 4000K.

So you should assume 2/3 of that (4000K -> 2000K), so around 1200lm for 2000K FC-40 KR1
Not great not terrible

Like we all know that FC-40 in such small light not going to be your main flashlight.

14

I would place the KR1 with GT-FC40 in a similar category as the Acebeam E70 CRI95 and Convoy S21D 519A. All compact(ish) high-CRI lights, with variations between somewhat floody (KR1), floody (E70), and very floody (S21D).