The There Are No Stupid Questions Thread

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: http://www.dx.com/p/aurora-ak-p7-5-ha-iii-ssc-p7-c-2-mode-900-lumen-led-flashlight-with-assault-crown-1-18650-15739 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)

:smiley:
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?

Thanks.

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.

Many different drivers do that and the electronics experts have a good explanation for the phenomenon. There are design options for drivers that prevent it. That is all I know.

Thanks djozz. I had hoped there might have been something like a firmware fix - three more of the drivers arrived this morning! :person_facepalming:

There may be a firmware fix, anyone?

I keep reading that a light can be locked out by unscrewing the tailcap slightly because the threads are anodized.

I understand that the cell circuit for the flashlight is completed when the tailcap is fully tightened, thereby making electrical contact with the un-anodized end of the tube and un-anodized retaining ring (or whatever) of the inner tailcap.

This implies that anodization is an insulator?

If that's the case, how durable is the anodization?

That is, how much wear can anodized threads tolerate before the anodization wears away to the point that continuity is created just through the worn threads?

How rapidly does the wear progress on properly lubed threads?

This has been discussed a while ago. If I recall right the cause might be the FETs gate still loaded after disconnecting the cell with a short tap. If this is true a hardware modification is required to solve the issue - which has been done in newer BLF driver designs.

Anyone?

If you unscrew the tailcap often the anodization may wear off pretty fast, depending on its quality. I’ve seen this with my Q8 lights already. Grease helps of course.

The anodisation is quite hard it has Mohs hardness of 9, 10 would be diamond. And you can have different thicknesses of it
With lube it should last therefore years.

Hi all new guy here and my stupid question is what does 2SPS mean/stand for?

“Hi all new guy here and my stupid question is what does 2SPS mean/stand for?”
2S2P means 2 serial, 2 parallel, like this:

4S1P is 4 serial, 1 parallel, like this:


2SPS isn’t a thing in battery circuitry.