The There Are No Stupid Questions Thread

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MascaratumB
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JasonWW wrote:
I’m not sure if anyone makes a Buck driver that small, so you might be limited to a 6v led.

The XHP50/70 are 6 volt, but there are others out there. I’m not too familiar with them. Maybe someone else can comment on them. (Nichia 144A is 6v)

The xhp50/50.2 does not like FET drivers. The 70/70.2 would be fine with FET.

I really don’t know what kind of drivers are available in that small size. I think that’s what you need to find out first. I’ve never built anything with such a small driver.

Maybe the driver size is similar to the earlier Tool AA. Have you checked Tool AA threads?

Sorry I’m not much help.

Hey Jason, thanks again for the replies!
Bummer that there are not small drivers for these kind of things Oops

The driver is custom shaped and has 14.3mm diameter and then some wings that make it go to 15mm.
But a shaved 15mm driver would make the job!

Then the LED pcb is also very small, like 12mm diameter, but the pill allows for something more!
I will have to explore what the host allows me to do, and seek what drivers vs Leds will fit the mod!!

Thanks again for the reply!

If anyone else has a hint on these stooooid questions of mine, please let me know Wink

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mitsuki08
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Can anyone tell me what I’m doing wrong? This is the first time I held a DMM and I can’t seem to measure current. I followed the manual to the dot but nothing is happening.

If it helps:
- I tried to set the dial to microamps and switched the red lead to the right port and it seems to work fine(as in the light lights up but can’t measure anything because it’s overloading).
- I watched djozz’s video as well as a reference.
- The light is a Convoy S2+, biscotti, 6×7135.
- I set it to DC mode(it shows in the LDC but it was hard to capture on the phone one-handed)

Note: Image shows the DMM in a negative value even though the leads are not touching anything

JasonWW
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mitsuki08 wrote:
Can anyone tell me what I’m doing wrong? This is the first time I held a DMM and I can’t seem to measure current. I followed the manual to the dot but nothing is happening.

If it helps:
- I tried to set the dial to microamps and switched the red lead to the right port and it seems to work fine(as in the light lights up but can’t measure anything because it’s overloading).
- I watched djozz’s video as well as a reference.
- The light is a Convoy S2+, biscotti, 6×7135.
- I set it to DC mode(it shows in the LDC but it was hard to capture on the phone one-handed)

Note: Image shows the DMM in a negative value even though the leads are not touching anything


Don’t exceed the amperage rating for the ports as you can blow fuses and the correct fuses are hard to find.

Everything looks fine. With that type of light you have to connect and then disconnect reconnect fast like a half press of a tail switch to cycle modes.

Make sure the one lead is touching clean, raw aluminum.

My meter reads the same regardless of polarity. You can try switching the leads around to see if it makes a difference with your meter.

Is the flashlight turning on?

Texas Ace Lumen Tube calibrated with Maukka lights

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mitsuki08
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Thanks for the feedback JasonWW.

JasonWW wrote:
Make sure the one lead is touching clean, raw aluminum.

I tried connecting the negative end of the battery with some wire laying around and connected it to where the red lead is touching and it turned on so I assume that’s a correct place to put it?

JasonWW wrote:
My meter reads the same regardless of polarity. You can try switching the leads around to see if it makes a difference with your meter.

It didn’t when I did it before. Just keeps showing a negative value from 0.2-0.5mA.

JasonWW wrote:
Is the flashlight turning on?

It doesn’t turn on at all. I’m not sure if it’s my lack of knowledge or the DMM is just defective. Voltage measures fine though.
JasonWW
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You might have blown a fuse inside or the fuse might be missing on the 10A side.

Keep in mind that DMM are only good for measuring low currents accurately. Above a couple amps they can be off by a lot. For accuracy you want to use a clamp style ammeter. I only use my DMM ammeter for moonlight levels and parasitic drain measurements.

Texas Ace Lumen Tube calibrated with Maukka lights

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mitsuki08
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JasonWW wrote:
You might have blown a fuse inside or the fuse might be missing on the 10A side.

Keep in mind that DMM are only good for measuring low currents accurately. Above a couple amps they can be off by a lot. For accuracy you want to use a clamp style ammeter. I only use my DMM ammeter for moonlight levels and parasitic drain measurements.

I see, I’ll try opening it up. Thanks for helping me out!

Edit: Confirmed it was a blown fuse. There was 2 inside and swapped it for the one in the micro amp one and its working now. Still need to find a new one though. Thanks Jason!

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One thing you learn quick about DMM’s is that you keep your probes plugged into the voltage holes.

When you put the probes in the amperage holes to measure something, put them back on the voltage holes as soon as your done. If you forget and then go measure a batteries voltage, the fuse will blow right away. Facepalm After you do that a few times and have to order special fuses you learn not to do it any more. It’s a real pain in the rear.

Texas Ace Lumen Tube calibrated with Maukka lights

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BurningPlayd0h
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Th558 wrote:
If 1+1 is 2, then shouldn’t 2+2 be 3?

No, because “3” already has an intrinsic and local value equal to 1+1+1.

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JasonWW wrote:
One thing you learn quick about DMM’s is that you keep your probes plugged into the voltage holes.

When you put the probes in the amperage holes to measure something, put them back on the voltage holes as soon as your done. If you forget and then go measure a batteries voltage, the fuse will blow right away. Facepalm After you do that a few times and have to order special fuses you learn not to do it any more. It’s a real pain in the rear.

+1 this

This is why I have two DMM’s dedicated to Amp measurements only Facepalm

BTW, those Aneng DMM’s are pretty precice. Considering the price.
I have an Aneng 8004 that’s only used for milli/microAmp/parasitic drain measurement. Compared to a calibrated Fluke DMM, the yA are “only” off by 1-2yA Grad

lightwonder
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Anyone having facebook problems atm

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> if the government tells you ….

Not Indiana: https://en.wikipedia.org/wiki/Indiana_Pi_Bill

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I’ve got a couple potentially stupid questions.

1) I’ve got a utorch lantern/bug zapper that takes a 18650. It has a sleeve inside that when removed it looks like it can fit a 21700. Will this break the light? isn’t the voltage the same?

2) Simon already said no, but if I had a convoy m3 that takes one 26500 battery and found a long enough tube to fit two 26500’s would it break the light? why?

Thanks!

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nydude wrote:
I’ve got a couple potentially stupid questions.

1) I’ve got a utorch lantern/bug zapper that takes a 18650. It has a sleeve inside that when removed it looks like it can fit a 21700. Will this break the light? isn’t the voltage the same?

2) Simon already said no, but if I had a convoy m3 that takes one 26500 battery and found a long enough tube to fit two 26500’s would it break the light? why?

Thanks!

1/ 21700 batteries are fairly new, and predominantly used in high-end flashlights. That’s why I think this sleeve is meant to fill the space needed for a 3*AAA battery carrier. Those have a diameter of a bit over 22.6mm.
Edit: a 21700 has the same voltage as an 18650, that does not hurt a bit. But I may be too long to fit.

2/ 2 batteries “in a row” have a voltage of 2*4.2V = 8.4V. You fry the driver when that is built for 1*4.2V.

You are a flashaholic if you are forced to come out of the closet, to make room for more flashlights.

HKSJOSHUA_
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I bet a 26650 battery may fit

And yes two batteries stacked together results in 8 volts instead of 4 volts

HKSJOSHUA_
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I found the perfect holster for the emisar d4s, I just received it today. It is a pistol magazine/flashlight holster I found at my local academy

Any way I can upload a pic on here to share? I may find the link on academy’s website and copy and paste it but I’d rather show you guys how perfect of a fit it is!!!!!

nydude
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thanks everyone! there will be more.

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HKSJOSHUA_ wrote:
Any way I can upload a pic on here to share?
You can’t directly upload photos to BLF. You’ll need to upload them to a photo-sharing site and post a link.

It’s not complicated. Here’s a how-to guide put together by BLF member ‘raccoon city.’

I recommend using imgur.com as the host site. It’s easy and you don’t need to create an account.

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HKSJOSHUA_
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Thanks figured it out from another blf member

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Guys, I can’t find the answer although I’m pretty sure there is one within BLF “borders”. Hence my post here – I feel stupid asking you for a shortcut instead of making full research.

The question is: how to calculate the size of hotspot at a particular distance?

Let’s say I want a hotspot of diameter =3 meters at a distance of 150 meters. (numbers are taken out from nowhere, so might be odd). Which LED should I choose (de-doming/slicing is within scope of my poor abilities)?
Or the other way round. Let’s say I have Samsung LH351D, how can I know what would be the hotspot size at distance of 150 meters?

Your hints will make my research way easier.

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I am by no means an expert but I’d say it’s all up to the reflector or optics. Too many variables to be able to use a simple formula.

1stein
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I found something relevant here
But my geuess is that’s not the only one. Anyway, thank you Enderman

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Mike C wrote:
I am by no means an expert but I’d say it’s all up to the reflector or optics. Too many variables to be able to use a simple formula.

I’m sure you’re right but since I’m interested only in hotspot I think the reflector has not that much impact?
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But it’s the reflector that focuses the light into that hotspot. Just see what happens when you don’t have any reflector at all, it turns into a mule light with no beam at all. With any given LED you can have widely different beams just by switching reflectors.

I didn’t know about Enderman’s calculations. At least with that you can enter some reflector data.

1stein
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Mike C wrote:
But it’s the reflector that focuses the light into that hotspot. Just see what happens when you don’t have any reflector at all, it turns into a mule light with no beam at all. With any given LED you can have widely different beams just by switching reflectors.

I didn’t know about Enderman’s calculations. At least with that you can enter some reflector data.

Yes, you’re right Mike, w/o ref it goes insanly wide. So if won’t have any other option I’ll use Enderman’s method.
However, the LED area are must have a meaning, since by just replacing the led you get more/less focus as well.

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Newbe question. Difference between Candelas/Lumen?

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1stein wrote:
Guys, I can’t find the answer although I’m pretty sure there is one within BLF “borders”. Hence my post here – I feel stupid asking you for a shortcut instead of making full research.

The question is: how to calculate the size of hotspot at a particular distance?

Let’s say I want a hotspot of diameter =3 meters at a distance of 150 meters. (numbers are taken out from nowhere, so might be odd). Which LED should I choose (de-doming/slicing is within scope of my poor abilities)?
Or the other way round. Let’s say I have Samsung LH351D, how can I know what would be the hotspot size at distance of 150 meters?

Your hints will make my research way easier.


There is only trial and error. Luckily there are already many different lights on the market so we kind of know how they scale up and down.

Basically it’s the ratio of die size to reflector size, assuming we are talking about basic flashlight design using a reflector. For a fixed reflector size, a smaller die creates a smaller hot spot and a bigger die makes it bigger.

For a fixed die size, a smaller reflector makes a bigger hot spot and a bigger reflector makes a smaller hot spot.

It’s easiest to just sample flashlights to see how they perform and decide if the hot spot is large enough and bright enough at the distance you want. If the hot spot is too small, you need to go with a bigger die or a larger reflector. If it’s too big, go with a smaller die or bigger reflector.

Typically a person will have a distance requirement, let’s say to easily see out to 200 meters. You can find lights that meet this requirement by looking for ANSI FL1 distance ratings of at least 600 meters. (Typically 1/3 the rating will be bright enough to see really well). Then it is a matter of how big of a hot spot do you want at that distance. A tiny 500 lumen black flat led in a Convoy L6 could easily do 600 meters, but it’s hot spot would be tiny. On the other extreme, a 6000 lumen xhp70.2 in the same L6 would also do 600 meters but make a huge hot spot. By keeping the L6 as an example host you have a full range of led die sizes to play with. Now you have to find the right compromise of flashlight size, weight, battery longevity, thermal control, etc… that best fits your needs.

Also keep in mind there will be a corona around the hotspot which will make the hot spot seem a bit larger. This means your “needed hot spot size at X meters” can actually be a bit smaller than you thought.

So based on what you need, folks here can get you in the ballpark, but it’s not an exact science. Reflector geometries and surface smoothness do tend to vary a little which throws off the calculations a bit.

Texas Ace Lumen Tube calibrated with Maukka lights

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Starkm32 wrote:
Newbe question. Difference between Candelas/Lumen?

Candela is a measure of light intensity in a tiny portion of a fully formed beam. This tells you how far the light will travel.

Lumens is a measure of all the light being produced captured and combined back together, integrated, and then measured. Lumens are much harder to measure.

So candela varies greatly based on the reflector and beam angles.

Lumens are not effected by the reflector* or beam angle.

*Reflectors due vary in the amount of light they absorb and reflect, efficiency, which does effect lumens.

Texas Ace Lumen Tube calibrated with Maukka lights

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