The There Are No Stupid Questions Thread

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Skylight
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Lightbringer wrote:
How hard are you gonna cook the LED if it only sits on a 10mm board??

Unless you’re gonna try to push multiple amps through it, not even Al vs Cu would make that much difference, let alone Cu-dtp vs -non-dtp.

Let’s say 3 or 4A in a multiple led direct drive setup.

I just thought it would be some sort of DTP if you scrape away the central part of the 3535 footprint and add enough solder to get a direct connection to the copper of the board. Does that make sense?

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Skylight wrote:
Lightbringer wrote:
How hard are you gonna cook the LED if it only sits on a 10mm board??

Unless you’re gonna try to push multiple amps through it, not even Al vs Cu would make that much difference, let alone Cu-dtp vs -non-dtp.

Let’s say 3 or 4A in a multiple led direct drive setup.

I just thought it would be some sort of DTP if you scrape away the central part of the 3535 footprint and add enough solder to get a direct connection to the copper of the board. Does that make sense?

Mmm, I see “10mm” and I’m thinking an AAA light. LOL

It’d work, but solder (Pb/Sn) isn’t the best of thermal conductors. Grind away too much to expose the Cu underneath, and you may have less conductivity vs leaving it alone. Plus, be sure to have an “overflow channel” so excess solder can squish out and the LED doesn’t float on the molten solder.

Someone did tests of various thermal compounds vs just squishing down (via screws) the board dry, and there was negligible difference.

Me personally, I’d leave ‘em as-is. Combination of laziness and diminishing returns…

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djozz
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Skylight wrote:
I have found some 10mm MCPCBs that are made of copper but not DTP.

Do you think it would be a good idea to remove the insulating layer below the thermal pad until the copper is exposed and solder the led to it?

Will the solder layer be too thick if I would fill up the gap between the copper and the led thermal pad with enough solder paste?


It will work well, I tested it 5 years ago. Maybe for 3535 boards the result is a bit worse than 5050 boards but I expect that the thermal path is still much improved compared to the situation with dielectric layer.
http://budgetlightforum.com/node/30532
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I need some advice and help determining which DC power supply to buy for flashlight modding.
Probably could get by without one but just want to learn as much as possible.
There are switch mode and linear, 30V 3A, 30V 30A.
I’m not an electronics tech but want to have more fun.
Thanks for not laughing Beer

I like this one, but is it the correct one ?
https://www.amazon.com/dp/B00O8DJ8QC/ref=sspa_dk_detail_0?psc=1&pd_rd_i=...

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djozz
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CNCman wrote:
I need some advice and help determining which DC power supply to buy for flashlight modding.
Probably could get by without one but just want to learn as much as possible.
There are switch mode and linear, 30V 3A, 30V 30A.
I’m not an electronics tech but want to have more fun.
Thanks for not laughing Beer

I like this one, but is it the correct one ?
https://www.amazon.com/dp/B00O8DJ8QC/ref=sspa_dk_detail_0?psc=1&pd_rd_i=...


I’m not an electronics geek myself, but have bought a few power supplies over the years for my flashlight hobby. My most used PS is a heavy lineair one but I understand that using a switched mode PS for what we do is perfectly fine. The one you linked is very cheap, so expect some imperfection, like bumpiness when finetuning the current, and spikes when switching the PS on, I expect you can blow sensitive leds with that (but not likely the power leds we are using). I think 5A max is a bit low, maybe 10A is more versatile.
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djozz , Thank You for that. I will wait and keep learning before buying one. Beer

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hank
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it registered at 1.73v which concerned me.

That falls in my “recycle this carefully so as not to set the recycling truck on fire” category.

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crazy.about.lights wrote:
I recently ordered a protected Panasonic ncr18650ga 3500mah cell it didn’t register on my charger. so today I put it on the charger again and it registered at 1.73v which concerned me. I’ve got it up to 2.23v now, should I try to get it above 3v or not?

Are you sure it’s protected? Measure the length.

A protected cell will cut off power once it reaches 2.5v. That is about the lowest safe voltage you can go. Below 2.5v the cells go through chemical changes which ruins them. They become fire hazards when charging. Keep tabs on how hot it gets.

I would contact the store you bought it from. It doesn’t sound like it’s protected, plus it’s ruined.

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djozz
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If the drain is very low, like what happens with a lighted tail flashlight, or one with high parasitic drain (FT02!!!), the protection circuit may not be triggered and the drain continues beyond the safe voltage.

Or am I mistaken with what some flashlight drivers do and will protected cells indeed detect the correct voltage and shut off even with very low drain?

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Thank you, djozz and Lightbringer for your advice regarding DTP and non-DTP MCPCBs. Nice and useful test you did there, djozz. Thumbs Up

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I think I managed to get very unlucky. It is an EVVA 10A protected cell but it was stuck in the mail for a week and it wouldn’t charge for a few days after it got here. My charger read resistance to be 999mΩ, so I think I’ll see what I can do when It comes to sending it back.

Thanks hank,JasonWW and djozz.

Gabe

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djozz wrote:
If the drain is very low, like what happens with a lighted tail flashlight, or one with high parasitic drain (FT02!!!), the protection circuit may not be triggered and the drain continues beyond the safe voltage.

Or am I mistaken with what some flashlight drivers do and will protected cells indeed detect the correct voltage and shut off even with very low drain?


Is this a random question?

The low voltage protection circuitry in a battery will cut power whenever the voltage gets to it’s lower limit, like around 2.5v.

The LVP in a driver like NarsilM and Anduril will only be active when the driver is active. For instance the light is left on at a low level. When you turn off the light, the MCU goes to sleep to reduce parasitic drain and the LVP is not working. Usually the parasitic drain, even with a lighted side switch, is so low it will take years to run down the battery, depending on the light model, of course.

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nydude
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hi, if I put this uv glass in my regular convoy s2+ will it work as a uv light?

https://www.aliexpress.com/item/32886058085.html?spm=a2g0o.productlist.0...

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ok trying to answer my own question. if i get that glass and this bead

https://www.aliexpress.com/item/33052474666.html?spm=a2g0o.cart.0.0.234a...

I already have a convoy s2+.

so I think I reflow the solder on the board. twist it out. reflow the solder on the LED. remove. then solder the bead to that board. switch out the glass. then screw it all back together and solder the board back?

seems simple enough. am I missing something?

thanks everyone.

JasonWW
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nydude wrote:
hi, if I put this uv glass in my regular convoy s2+ will it work as a uv light?

https://www.aliexpress.com/item/32886058085.html?spm=a2g0o.productlist.0...


Yes, but it won’t be very bright.

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JasonWW
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nydude wrote:
ok trying to answer my own question. if i get that glass and this bead

https://www.aliexpress.com/item/33052474666.html?spm=a2g0o.cart.0.0.234a...

I already have a convoy s2+.

so I think I reflow the solder on the board. twist it out. reflow the solder on the LED. remove. then solder the bead to that board. switch out the glass. then screw it all back together and solder the board back?

seems simple enough. am I missing something?

thanks everyone.


First you need to make sure your S2+ driver will not burn up that led. Ad says no more than 0.5A from driver. If you have the 8×7135 driver, you’ll need to remove all but 2 of the 7135 chips. 0.7A is probably okay.

It’s better to buy the led on the 16mm mcpcb so you dont have to reflow anything.

You won’t need the glass lens if you have the UV led.

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nydude
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cool. thanks. appreciate the help.

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if I wanted to upgrade a tail switch for a tail clicky, is the PCB the upgrade or the switch itself.

if it is the switch can someone point me in the direction of a switch that would be an upgrade to a standard convoy tail switch?

ive ordered a few of these PCBs
https://oshpark.com/shared_projects/TCY22964

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DoNkEyConN wrote:
if I wanted to upgrade a tail switch for a tail clicky, is the PCB the upgrade or the switch itself.

if it is the switch can someone point me in the direction of a switch that would be an upgrade to a standard convoy tail switch?

ive ordered a few of these PCBs
https://oshpark.com/shared_projects/TCY22964


I’m not understanding you. A “clicky” is a type of switch. You want to change a switch for a switch and have it be an upgrade?

Can you be more specific, what light is it?

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JasonWW wrote:
DoNkEyConN wrote:
if I wanted to upgrade a tail switch for a tail clicky, is the PCB the upgrade or the switch itself.

if it is the switch can someone point me in the direction of a switch that would be an upgrade to a standard convoy tail switch?

ive ordered a few of these PCBs
https://oshpark.com/shared_projects/TCY22964


I’m not understanding you. A “clicky” is a type of switch. You want to change a switch for a switch and have it be an upgrade?

Can you be more specific, what light is it?

I just want a switch I can run high amps through without issue, I have ordered the switch PCBs do I need a different or ‘upgraded’ switch or would say the standard switch from the convoy L6 suffice.

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The standard L6 switch seems to hold up really well to like 18 amps or more. The weak part of the mechanical switch is the contacts. Whenever they close you get a power surge and maybe a flash. Not much, but it can build up carbon residue or something which adds resistance.

I’ve got spare L6 switches, but my original never had any problems. I swapped a new one in and measured no difference in lumen output.

If you want something really robust, Lexel was offering a FET based switch, but it doesnt fit inside the light, it mounts outside it.

For a more conventional design I’d stick to the stock switch.

I dont know of any upgrade version to the L6 switch, but you might ask on a L6 thread.
http://budgetlightforum.com/node/43503
http://budgetlightforum.com/node/50372

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how crazy is this
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Potted lights? Is there a list somewhere of what lights are potted? Does it really make much difference or is it still pretty much the luck of the QC draw?

I ask this as I have been playing a lot with my new th20 lately and of course have dropped it a couple of times on concrete. Other than the physical dings there are no ill effects and frankly with my experience with Thrunite I don’t expect any. Perhaps I have just been lucky and perhaps Thrunite has decent quality control but isn’t the engineering of how the pill is put together and mounted a significant factor for at least what should be likely reliability? Are Thrunite lights potted? Seems quite a few members mod the th20 specifically to get a different emitter so this should be a known thing. All I know is they have excellent thermal management and hold up to drops. This could be because of potting? There is so much I don’t know.

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Could someone differentiate between the pros of Emisar D4SV2 vs D4V2, please? Grad

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Thanks for your help JasonWW

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Starkm32 wrote:
Could someone differentiate between the pros of Emisar D4SV2 vs D4V2, please? Grad

1. D4S is larger and heavier.
2. D4S takes larger cells which can have more capacity.
3. Larger optics focus the light more. With the same LEDs D4S will produce a much smaller but much brighter spot.
4. Extra mass and surface area of D4S mean that it handles heat better. It will run on Turbo for longer and it will sustain a little more light.

I think these would be the main differences…

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JasonWW wrote:
nydude wrote:
hi, if I put this uv glass in my regular convoy s2+ will it work as a uv light?

https://www.aliexpress.com/item/32886058085.html?spm=a2g0o.productlist.0...


Yes, but it won’t be very bright.

No, a regular led does not emit UV, a filter that selects for UV will leave no light left at all.
djozz
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JasonWW wrote:
nydude wrote:
ok trying to answer my own question. if i get that glass and this bead

https://www.aliexpress.com/item/33052474666.html?spm=a2g0o.cart.0.0.234a...

I already have a convoy s2+.

so I think I reflow the solder on the board. twist it out. reflow the solder on the LED. remove. then solder the bead to that board. switch out the glass. then screw it all back together and solder the board back?

seems simple enough. am I missing something?

thanks everyone.


First you need to make sure your S2+ driver will not burn up that led. Ad says no more than 0.5A from driver. If you have the 8×7135 driver, you’ll need to remove all but 2 of the 7135 chips. 0.7A is probably okay.

It’s better to buy the led on the 16mm mcpcb so you dont have to reflow anything.

You won’t need the glass lens if you have the UV led.


With most UV leds, very likely with this one as well, the filter is a very good idea, you do need it, because it filters away all of the visible stray light that these leds emit together with the UV light. Without a filter it can only be used for photochemical curing, with a filter it makes the UV flashlight suitable for observing fluorescent stuff.
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djozz wrote:
JasonWW wrote:
nydude wrote:
hi, if I put this uv glass in my regular convoy s2+ will it work as a uv light?

https://www.aliexpress.com/item/32886058085.html?spm=a2g0o.productlist.0...


Yes, but it won’t be very bright.

No, a regular led does not emit UV, a filter that selects for UV will leave no light left at all.

Are you sure? I thought I saw people installing these over white leds and it has a very weak UV output.

If they block everything, what is the point of them?

My UV light doesnt use a filter and it’s great at showing fluorescing objects. I do see some visable light on certain objects. Is the filter supposed to block this visable light?

Personally, I would suggest that people just buy a good quality UV light from someone like Sofirn or Convoy. It’s going to be way more powerful then the LED mentioned above.

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djozz
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The led mentioned above may be pretty decent, at least the (quite extensive) specifications reproduced on the aliexpress pages mention an output of 900mW at 700mA, that is among the best around.

The output under 400nm of a typical royal blue led used under the phosfor in white leds is virtually zero. The ZWB2 filter does have some transmittance in deep red, maybe that is what people see?

The point of a UV-pass filter over a white led source is indeed pointless.

Without having a filter, your UV-light does show the strong fluorescence sources well, like white paper and glowinthedark stuff, but fluorescence of weaker sources (like stains, but also plants and most insects) is washed out by the white-ish stray light that most 365nm led emit. Unless your led is a Nichia 365nm led (like the 276A) in near-new-condition, those emit fairly little visible light. Try a filter on your light and be amazed by the new world it creates Smile

Agreed on the Convoy UV lights, do try to get one with the ZWB2 filter.

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The led on the Convoy light uses 5 × 7135 or 1.7A. Am I wrong to assume that led is going to be much brighter than the one rated for 0.5A?

I do have the 276A. It’s great. Maybe I’ll try a filter since they are cheap.

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