Q8, PMS SEND TO THOSE WITH ISSUES BLF soda can light

What dangers, could you briefly point them out? All I can think of is the fire hazard if the light is activated on full accidentally and left lying somewhere it shouldn’t be.
(Yes, I’m a newb who bought his first soda can light).

And a couple questions on batteries for Q8:

  1. Why do you recommend protected batteries when the light already has built-in undervoltage protection?
  2. Why do you recommend Samsung 30Q, the notorious high-current batteries? This flashlight does not seem to require high-current cells:
  • The LEDs are rated as 10W. Say, you over-drive them to 15W. 15W / 3.7 V = 4.05 Amps. Divide by 80% driver efficiency (a pessimistic figure, hopefully), and you get just a bit over 5 Amps per LED. Four LEDs, four batteries. Any regular non-high-current (5 A) battery should suffice, as long as you’re running all four. Where am I wrong? Does each LED consume more than 4 A in turbo?

Well, there’s all the inherent risks of using lithium-ion cells. Treat them properly, and you’re probably fine. But, treat them improperly, and there may be a safety risk. There are tons of threads on proper 18650 care, so you’re probably already aware.

There have also been reports of what happens if you accidentally insert one of the 18650 cells the wrong way into the Q8. It goes bang, and fries the springs. That’s if things go well…

And, as you note, this light can catch stuff on fire if you hold flammable things close to it on max. Or burn a hole in a bag that you’re carrying the light in and the switch is accidentally pressed.

Some of those are common issues with all high-power lights.

I don’t, but protected batteries will prevent shorts as mentioned above, so are better for safety.

This light uses a direct-drive when on high. That means that the higher the voltage of the battery, the higher the output of the light. High-drain cells have less “voltage sag” when driven hard, than regular cells. So, a high-drain battery will give you higher output.

If this light used a boost-driver for regulated output, then lower-drain cells might be okay. But, that’s not how it was designed (probably because of cost).

Thorfire did one single test with a full run on maximum.
As far I remember it run ca. 40 min till the temperature starts to fall.
Don’t know which batteries they used. I assume 3500mAh ones.

The light survived.
So the lamp should cope with the heat.

@Alternety
If you don’t like the UI find one who reprogramm the light.

- set the time to enter setup to 30 sec (which is now 8sec) and it should work

- or remove setup completely

  • or flash another firmware

That 30 second idea sounds good. 8 seconds can be accidental by someone trying to see if it will go higher, they will have given up on that idea long before 30.

- protected are recommended for legalreasons. Remember there are settings you can switch the protection off.

  • It’s a BLF Lamp. Of course it uses more amps. If you clean all connections it should suck 18 Amps. With bypassed springs nearly 20A.
    (at turn on)

I think he has 3.

Protected cells usually have four or five different protection circuits. Over discharge protection is just one of those.

With a direct drive light the internal resistance of the batteries plays a major role in the output of the light, so does the forward voltage of the emitters, the chemical mix of the batteries, etc…

If you look at the 30Q and the Sanyo GA both batteries can easily output more than 5 amps, but if you put them in a Q8 you will get a higher amp draw (higher lumens) using the 30Q compared to the Sanyo GA (maybe 500 lumen or more). A protected Sanyo GA might loose 1,000 or more lumen to a 30Q. The protection circuitry typically adds a lot of internal resistance.

Look at this chart here.

The more you study direct-drive lights the more you’ll start to see how the battery directly influences the emitter.

You can’t even run the Cree xhp50.2 direct drive, even on little 18350 celks in series, because it will pull too much current and blow the emitter.

I guess Tom E. used 8sec to be able to switch quickly between RAMPING and MODES.

The sequence to change is:
Hold the button till it blinks the first settings, then one or two clicks and then hold the button till the lamp confirm with four blinks.

In retrospect I think it would also better to change the first setting to
1 click = RAMPING
2 clicks = MODES
Today it’s reversed.
Only for the reason RAMPING is mostly used and people try to switch off the lamp if it starts blinking.

Oh, I see! Didn’t realize that. Thanks.

Gotcha, thanks for the reply.
So the turbo mode is just shoving as much current down the LED’s throat as it the Ohm’s law will let it. Is that safe for the LEDs? Not that I’m concerned, I personally don’t intend on using that mode for prolonged periods of time, just curious if the LEDs may degrade when used like this, or Cree is just being super conservative in rating XP-L at 3 A max.

Thanks for the chart. By the way, I have never seen a high-current protected battery, by the way. My local battery shop that’s known for selling original Korean and Japanese cells does not have them, and by “local” I mean it’s probably the best in the country. It only offers protected 5A cells. But I assume protected 30Qs do exist.
Assuming I will not insert the cells the wrong way into my Q8, do you think protected batteries are a must? What kind of protection do you think is the most useful for Q8 as far as preventing undesired situations?

Yes, the leds may not reach the rated 50,000 hours. But also, in the Q8 and many other modern flashlights, the leds are mounted with an extreme good heat path away from the led, that makes a huge difference while the Cree specs do not take that into account. On this forum we test leds in that environment and find what the real performance is. But we do not see yet what happens after a few thousand hours.

If a LED ever getting dim after a few years you can swap it out with a new more efficient one.

In the Q8 modding thread there are 3D printed protection rings which make sure a flat top (or reverse end) doesn’t make contact.
Or you fit something into the head which is ca. 0.2mm higher then the brass contact ring. If the nipples are higher than 0.3 the batteries make contact.

Lock the lamp out when you transport it. If its lying on the floor of a car and it rolls around, it can switch it on by its own weight.

That’s pretty much it (on a FET driver).
Turbo mode means the FET is constant closed or 100% duty cycle (I hope that’s correct) so it’s like a solid wire from the LEDs to the battery. You can partially limit current through resistance. Smaller guage wire, resistance in springs, resistance in the FET, different batteries, etc…

Other driver types, Constant Current, Buck, Boost have controllable max outputs.

The protection circuits add a lot of resistance so it defeats the purpose of using a high current cell. You typically see high mAh batteries used with protection circuitry. (EDIT:Imalent has protected 30Q cells rated at 15A)

Any type of protected battery in the Q8 would probably limit it to 4,000 to 4,500 lumen I’m guessing. That’s still pretty bright. If your not after the most lumens and prefer safety, then using protected cells are a good idea.

Thus particular LG MJ1 protected cell can do 12 to 13 amps.

It’s still not going to allow a high amp draw on turbo, though due to the extra resistance.

On other driver types, the extra resistance from the protection circuitry doesn’t hurt performance at all.

Typical things the protection circuitry does is prevent:
Over charging (stop at 4.2v)
Over discharging (stop at 2.5v or similar)
Over temperature
Over current
Reverse polarity

Side note:
No batteries come from the manufacturer with protection circuitry. It is only added by other companies and the little circuit boards can vary from one company to the next. You can have the exact same battery with protection circuitry added by two different companies and have two different maximum current limits.

And you probably won’t know what you are getting either - which is why I don’t own any protected batteries. Over and Under voltage protection is fine, as is reverse protection, but I don’t want a battery that will cut out at an unspecified current, or unknown temperature, without warning.

Based on what I’ve read in Cree’s LM80 testing (which tests LED lifetimes), it seems heat is the largest factor in determining LED lifetime, and current is a distant second. At least, within normal ranges. The LED junction point can handle temperatures of 85C-100C okay, but beyond that they start to age the LED prematurely.

No doubt over-driving the LED will cause it some additional aging, but is 20,000 hours or even 10,000 hours so bad? How often are you going to be running the LED at high output? 10,000 hours will require about 10,000 full battery cycles. Even if you drained the batteries in your light each and every night, it would still last 27 years until it dimmed to the 70% threshold. I doubt you’ll still be using the light 27 years from now.

That’s not true. The key is to know what your buying and not to buy just any old protected cell.

Stores like https://liionwholesale.com and www.mtnelectronics.com give detailed info on the protection circuit of each battery. Keeppower also gives specifics on their protection circuitry. Also, you have certain light companies that add their own protection circuitry to cells such as Imalent. They have a protected version of the Samsung 30Q rated at 15A. (I forgot about this one until just now). Plus I’m sure theres a lot more I don’t know about.

As good as stores such as Banggood and Gearbest are, I would not recommend buying protected cells from them. They are so large that their stock is always being replenished and might be replaced with a slightly different protection circuit added on that has different specs. The store may not even realize the product has changed slightly.

joechina - YES: excellent idea.

click = RAMPING
2 clicks = MODES
Today it’s reversed.
Only for the reason RAMPING is mostly used and people try to switch off the lamp if it starts blinking.

I believe that will fix the only issue I have with the light. I believe in previous posts I have said the issue is being able to easily entering flashing mode and hard to get out. It is more intuitive to press the button and get ramping.

Please, don’t start on easy and hard. As I have also stated THIS IS INDEED THE FLASHLIGHT I WANTED. I HAVE FOLLOWED THE DEVELOPMENT FROM PRETTY MUCH THE BEGINNING. I bought them when everything was well known.

I did not pay close enough attention to the impact of the actual press sequences when NARSIL was being created. Even if I had paid more attention, I probably would have missed the impact of sequence I view as a problem.

The team did an incredible piece of work. It just needs to be a teeny bit more user friendly (I am talking only about the two button sequences) for sale on the open market. And that may well become the majority of the sales volume.

Contrary to some opinions, I am not an idiot (at least I think so). I am interested in some of the other functions in NARSIL. But not for a civilian, as it currently works.

An additional feature of getting a protected cell is that you will have a button on the positive end. You can find unprotected cells with buttons.

The button is useful for getting full contact in some lights, and probably chargers.

alternety
You can ask in a separate thread if somebody near you can change the firmware to your liking.
Maybe Toykeeper if you ship the lights to her.