Fireflies ROT66 review (3x18650, 9x219B)

Awesome review as always, with useful quantified measurements well beyond what most people provide. I wonder how they got 219b emitters.

I’m not happy to hear that the driver is glued, but hopefully there will still be a way to access it.

I couldn’t tell from the pictures, but are the batteries parallel or in series? Does the lighted switch turn off completely sometimes, or only halfway off?

Thanks for the comment and thanks for helping Tom E and Fireflies with the memory bug. Let’s hope it works and they have the fix applied soon.

The batteries are in parallel. Haven’t seen the switch backlight turn off, other than half of them are off when the light is on or it is in lockout mode.

Half are probably wired to Lexels L pad and the other half to the LS pad. L is the normal mcu controlled pad and LS is the permanent on. This is a new thing on Lexels drivers.

Damn that light is nice.

It’s using BeCu C17500 springs, has a NarsilM FET 3 channel driver, using rosy 219Bs R9080, a bit too rosy though, and a very nice form factor.

But that’s just it, they aren’t too rosy. Just makes everything else look green, but objectively at –0.0020 to –0.0030 duv on the mid output levels, the end result seems pretty much ideal to me.

Nice pics and collection. I would like to have one too. And thanks for the measurements.

BTW recently watched maglite mods :slight_smile:

Here’s the effect the lens has.

Transmission: 98.4%

Without it the beam is a bit rosier (duv –0.0030 vs. duv –0.0018).

With

Without

A relatively small change, but I’d probably like it better without the AR lens. A bit closer to my ideal CCT, with a bit of extra pink, is a double win. :slight_smile:

The difference with vs. without lens is practically imperceivable with a CIE 2000 deltaE of 2.2. Everything under delta E 3 is difficult to notice with the naked eye.

Really good review, thanks maukka :+1:

Awesome review!

Glad I ordered the Nichia version and not the XPL HI version.

Excellent review once again! Think I do have a potential fix, can't be sure but potentially. I'll be talking to them today.

Still wondering about the lumens. In theory this light should be equal to 3 triples, 1 batt per 3 LED's. I don't know how the path from the LED's through the battery is, ex: thickness of LED wires, etc., quality of springs, but if an equally tested 219B triple could be tested for comparison, it would be nice to know.

3860 lumens means 429 lumens per LED, or 1287 lumens for a FET based triple.

I only happen to have an Astrolux S41S with 219B sw40k R9080 and MTN17ddm FET driver with bypass on the driver and double springs in the tailcap. It only does 900 lumens max (at 0 sec) with a fully charged 30Q.

edit: another point of comparison is a triple 219C R9050 BLF X6 with a FET (h17f driver), it does 1620 lumens at 0 sec, 1560 lm at 30s.

That's interesting, not the same LED's but big difference per LED.

Thanks Maukka, great review as always.

At 65 degrees, is it still possible to hold the flashlight?

Found another 219B triple, edited my previous comment.

edit: and realized it is actually a 219C CRI90 triple…

Nice review, thanks! :smiley:

65°C was at the head, it takes time to travel to the rest of the body. 65°C is too hot to hold, about 50°C is what I can handle for a short while.

Thanks Maukka

Fireflies mentioned larger domed LEDs like LH351D would not fit. Is this true?