New Folomov 18650s

On the stock cell fully charged and on turbo, output starts turning strange colors, blue I think.Other modes are regulated and work fine. With the cell as shipped at 3.8V, turbo works fine but only ~600 lumens. Dunno if it's just my unit or a driver problem, or something...

My blue beam tint problem went away after I heard/felt a 'pop' in the head area. Weird - still gets very hot and output drops hard in the first 30 secs: 626 lumens at start, 476 lumens at 20 seconds. These #'s are way lower than specs. I measured "hi" mode at 273 lumens, med=157, lo=73, lowest=16, moon=0.6
Specs say 900-300-150-50-10-0.5, so in the ballpark but turbo should be at 30 secs, which is probably ~450, 1/2 of what they spec'd.
Wish I knew what that 'pop' actually did -- interesting.

Nothing I can do to mod this, unless someone does a driver PCB design for it, even still, space for parts is tight because of the switch, and the other issue how batt+ and batt- are handled.

That’s my plan. How does the driver / switch actually work? How does the signal get to the driver in the head? Is the method used suitable for narcelM (i.e. can the tail button trigger like a standard e-switch press for the FW or would it have to be custom everything)?

Too many dunno's. Can't get the head apart so dunno what's there - think the driver is the tail board in the pic above. Uses a small 20 pin quad pack MCU. I assume for LED power, batt- goes thru the body up to the head.

What’s the diameter of the tail board?

And why on earth is the only resistor on the damn thing labeled R14 lol?

Edit: just thinking out loud here, how does the MCU in the tail get batt+?

16.9 mm. Think I mentioned that I measured 51 ohms between the brass button and the head shell, so, there's some connection there. I was think'n it's something like PD68's tailcap LED's. There's no other wire running head to tail so it must be using the battery tube shell.

Nice looking light. CW version available?

@TomE
Also received mine today.
Tried it with couple of different fully charged batteries but no angry blue visible.

You have probably been unlucky and got a lemon…

Ok, think this proves it's this one piece.

This is also weird. While testing, in a higher mode, think turbo, I heard/felt a 'pop' coming from the head which I really thought was the LED blowing the silicon bubble, but instead, the blue tint shift went away! It still gets hot quickly on turbo, but the tint shift issue is no longer. Didn't notice any physical damage to the LED either. Wonder if maybe it wasn't reflowed properly, then the heat melted the solder some what and re-seated the LED better on the pads. A bad reflow can cause the tint shift, from what I thought.


UPDATE

Even though in the initial use of the flashlight I didn't notice any angry blue, this evening after turning it on I indeed saw that the tint turned blue after staying for a couple of seconds in Turbo.
So TomE , it seems that there is something clearly wrong in the flashlight in general.
I shall send a message to Fomolov to let them know about the issue.

It could be simply that the 219D is not capable of high current.

Hmm, tomorrow I will fire up my bench PSU to see how many amps it takes before the LED turns blue.

By the way, the whole driver circuitry seems to be implemented into the tail, as shorting the tube with the BATT- creates a direct drive.

Did'n't check specs, but yes, seems like the 219D is low Vf LED, so amps can go crazy. That pic I took of the tail PCB certainly appears to be everything a fully working driver needs - I'm assuming that is a full driver, and at the head, is probably something simple like a resistor or something, no smarts. Got a couple of 18650S owners over on FB (Flashoholics Anonymous group) saying they don't see the blue shift on turbo on full charge, but mine is not showing that now as well. May have to risk an attempt to get the head apart.

Just got my 18650s.

Preliminary impressions:

  • Out of the box quite nice. Great fit and finish and nice compact size. No sign of blue-shifting tint when I used the partially charged cell that came with the light.
  • But then I used the built-in USB to fully charge the folomov cell and PROBLEM!!! When turned on in turbo the light blue-shifts within 5 seconds and output drops dramatically. Instead of 800 lumens it looks like its only outputting 100 lumens.
  • Once the light is warmed up by having been turned on and off for 5-10 seconds, the problem is worse. Turning the light on while it is warm causes the blue shift and reduction in lumens to happen almost instantly (less than 2 seconds).
  • and all of this is with the cell that came with the light! It’s not even a high discharge cell I assume.

My guess is the LED simply can’t take the amps. Either that or the LED is defectively installed. If anyone can get the head open it might be worth swapping the LED to something else. Perhaps XPL HI.

When my 18650s arrives I will not switch it on but directly remove the led for testing!

thats so odd…i didnt use the usb to charge, but charged the batt in my own charger, and dont get that.

was the cell overcharged ?

The most interesting thing about this light seems to be its tail-mounted driver with no extra channel to run BAT+ back or run the switch signal forward.

How does that work? Does it seem like something which might be useful for BLF designs?

I agree. I’d LOVE it if someone made a tail mounted e-switch driver that didn’t need the extra channel and sold it on Mountain Electronics. :heart_eyes: :heart_eyes: :heart_eyes:

No idea. I’m at the office right now and don’t have a way to test voltage. I charged it until the little red LED on top of the cell turned green.

I agree - it's fairly unique, but I think the UltaFire UF10 had the same design. Here's the UF10 driver from the tail:

I really like the UF10, same sort of tail e-switch, but much simpler UI. All I did was swap the LED/MCPCB,and maybe wires to get more output and added bypasses.We use it about every night with the dog.

Ohh, this is the PCB at the head, so there are some surface mounts but no smarts, I believe:

This is how I tested for amps:

tail assembly:

I went dedomed in the UF-10:

The pics on the UF10 were all from Aug 2016.