The There Are No Stupid Questions Thread

  • Lumens are how much light is given off
  • Lux is how bright your surface will be
  • Candela measures the visible intensity from the light source.

If you use a Efest 650mah purple It might do pretty good judging by djozz”s test. Top 14500 cell out at the moment.
I’ll take a guess, maybe 2100 lumen’s at start and falling fast.

Hum, nice to know that! I have 2 Efest IMR ready for it! Just need to find the “perfect” host to try it!
Those numbers are good, but of course will be quick fall, for sure! I will use it for small bursts probably!

Thanks for your answer :wink:

Why do we keep hoarding flashlights?

How do those million volt hand held stun devices I see advertised produce that much voltage from a battery that small?

They’re “Chinese volts”, kinda like “Chinese lumens”. You know, how a 3×AAA light with Latticebright XP-E lookalike chip can produce 2,000 5,000 8,000 lumens.

Now THAT is funny

Actually, I thought I was just being a wiseass, but:



10,000 lm!!!1111oneoneone


And the really bad thing, is there are uninformed people that fall for it. :person_facepalming:
And they think its the greatest thing ever since a 2D mag is what there use to until I pull out my D4. :smiley:

Yes and no.
Sure most of those ratings are exaggerated. But producing a high voltage from just a single battery is no rocket science. The problem is when you want some power. Meaning, increasing the amps. Those devices might have a huge voltage but there current is very low. Dont forget that just 20mA (out of my head, exact figure can be slightly different) trough your heart could kill you.
You might ask now, but why is a hot rod flashlight that is pushing 10 or more amps to the emitter not dangerous?
That’s because the voltage is too low. Our skin has a very high resistance and thus a low voltage wont hurt us. That’s also why many (‘insulating’) materials that are being used in or around electrical equipment are rated to a certain voltage. Above that there is a possibility that the electricity can go trough it.

I went to my father last weekend and he was proud for his new “very bright light, as bright as the one you gave me a few years ago”, which he purchased locally online for 10-15 euros.

The one he referred to was this: and no, his new light isn’t that bright. It has a generic XP-E sized led pushing 100-150 “throwy” lumens, due to the tiny emitter. I was carrying an S41 Nichia at the time with a fresh Q30 which I shined to the ceiling saying something like “that’s not bright, this is bright”. My brother nearly choked laughing.

Uh-oh. I know the rest of this story…

Yeah, I’ve gotten that. “Lookit my bright new light!!” Love when I get the follow-up “It’s probably even brighter’n yours!”, referring to my little 1-mode ~500lm ’502.

Then we turn off the lights and do a ceiling-bounce test. Yeah, their “bright” lights are probably 100lm-150lm.

My favorite was a LB-fueled C8 wannabe. Sure, nice tight hotspot, quite bright, but 100lm concentrated into a small disc. Just for s&g, I trot out my C8A. The C8-wannabe illuminates the room, kinda, sorta. My C8A lights up the room as if someone flicked on the room-lights. :smiling_imp:

I just wish I had an audience for that one. :smiley:

Probably by self inductance from a coil, which can generate very high voltages (probably not 1 million volts though)

Oh man, I just thought that since I carry a Nitecore Tini on my keys, I should be shining that instead of my pocket light. That little thing amazes me every time I turn it on, I can’t imagine how it will look to the eyes of a non flashaholic holding a full sized 100-150 lumens “Police Tactical 10000 lumens Maybefire” :smiley:

Put simply, because it's the voltage produced by the battery chemistry that they use.

Different chemistries produce different voltages.

Can AMC 7135 380mA chips be stacked on top of 350mA chips?


Yes, no problem.

Ok thanks! (again)

I recently purchased a BLF X5/X6 driver from Banggood, and it produces a bright flash when switching to low, even from off. Do they all do that?

My turn!

1) Can you DD an XHP70.2 with 3S/9V?

2) Driver recommendations for a max-effort Trustfire TR-J19 - running 3x XHP70.2 P2 1A (likely 2S/6V)?

I have a TR-J19 which can run either 32650 2S or 3S, with a really bad driver in it. It’s been collecting dust since I bought it, and I want to update it. It’s massively heavy so it can take a lot of heat.