Fireflies ROT66 Flashlight

It doesn’t. It’s basically just battery voltage minus ~0.25V.

I’ll try it, but it’s very small.

Okay, managed to get the wire connected there, and it’s working. It turns red at about 3.55V now instead of 3.30V, but that’s okay. Also, it can’t do the “low” mode like the button LEDs do, so it turns off instead.

This is what I was trying to do earlier, but while squinting at the driver I didn’t see a good place to attach anything. The inward side of that resistor is just barely big enough for a thin wire though.

Maybe low mode would work if you increased the LED brightness with the trimmer.

No, low mode is way too low for the aux LED board to work. It turns off when it senses low voltage, and the “low” mode is far below its “off” threshold.

Anyway, I did some quick measurements. My light box is not calibrated with anything resembling a reputable reference light, so these numbers should not be taken very seriously, but here is what I got at some key levels:

219B version:

  • 115/150: 780 lm (highest regulated mode)
  • 125/150: 1353 lm
  • 130/150: 1822 lm

SST20 4000K:

  • 115/150: 923 lm
  • 125/150: 1485 lm (highest regulated mode)
  • 130/150: 1911 lm

Levels 115 and 125 are the top of the Nx7135 regulated modes, depending on which driver is used (7 or 14 chips).

I included level 130 because it is the “panic” threshold. Above this level, any overheat condition will cause the light to quickly ramp down to level 130. Below this level, it does normal PID regulation to search for a stable level.

From Lexel’s description there is an LDO regulator on board, which could account for the 0.25V drop. It also supposedly drops out at 3.0V, which seems a bit high to me, but safe.

Presumably the aux. MCU has some way of sensing Vbatt before the regulator. Otherwise it would be rather pointless. Given that it only does one trivial job anyway, it seems to be rather a waste. Perhaps if serial comms. could be established with the prime MCU via the button LED circuit, there could be some potential for clever tricks.

Not really sure what the purpose of the regulator is, (or the MCU) but heigh-ho.

@Fireflies: could you tell us how to unscrew the glued driver retaining ring without damage, please?!

The aux LED board expects a direct connection to the battery. This allows it to measure voltage directly. It then has its own LDO for powering the LEDs at a consistent brightness.

The 0.25V drop is from the diode the MCU uses for reverse polarity protection.

I see.

Using a diode for reverse polarity protection is quaint.

A PFet will do a better job, with essentially zero voltage drop, for much the same price.

That’s haught.




Today I have Andruil from 30.09. Version 219 flashed. In Moon mode, the LED flickers. Can the problem be solved? Floor level is at 2.At level 3, the problem is not.

I tried six Fireflies lights/drivers and none of them flickered on level 1/150. The lowest level runs at the very edge of the hardware’s capabilities though. Are the batteries low? Is there a loose or extra-long wire?

Regardless, part of the reason why the floor level is adjustable is because of hardware variations. If the lowest level is too low, use a higher floor.

Nice.

Batteries were full and cable to the led I exchanged they are 25mm. I will test it with the original cable. It does not bother much and if I go to level 3. Thank you very much

Bump

I built a C8F triple with a FET+1 driver from Mountain Electronics. I have to put it on 3 as well otherwise it flickers. This is with different driver and LEDs (LH351D) and 1S battery. Probably the 7135 chip cant go lower.

Last I checked, Mtn uses the 380mA chips with a sailboat on them, and they don’t perform well at all at low levels. Acting weird at level 1 is probably normal for those.

Fireflies uses the 350mA raptor claw chips though, which are generally very good at low levels.

I’m guessing you tried a strap wrench already?

This is not the answer you want, but if they used Loctite, it breaks down somewhere between 150° C (max rated service temperature) and 250° C (temp they recommend for removal).

I use a heat gun from time to time to remove Loctited bolts, but bolts don’t have electronic components or solder, which melts somewhere around 180° C.

I don’t know if it weakens somewhat below that temperature. Heating the light might work, or it might kill it before you actually break down the adhesive.

For those who don’t already own the light, I noticed yesterday the website does now have the option to select an unglued bezel, warrantied only against defects on arrival.

Unless money is really tight I would just sell the glued one and order a new one if you absolutely must access the bezel. It’s not worth the risk of melting the optic and other damage when you can order it unglued from the factory.

A strap wrench won’t work on the driver retaining ring.

That part probably doesn’t need glue at all. Usually the point of a retaining ring is to avoid the need for glue.

It was very difficult to open. The thread has been damaged and is no longer correct. It helped me to drill the holes deeper. As far as possible no pressure should be exerted from above to avoid damaging the thread.I used needle nose pliers, spanner and vise.

Exactly!
One problem are the conical holes
in the retaining ring which I cannot grip well with a mounting tool. Therefore I’m not able to apply much force.
This is my most expensive stock light up to now and I don’t like to damage it. If Fireflies doesn’t help I finally will drill additional holes for better grip and use the heatgun but I’m still hoping for their response. Fireflies should know a method for disassembling defective lights - or do they put them in the wastebasket?