Remote FET / capacitor tail switch board group buy (collecting interest)

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Zappaman
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Richfire looks like the source to me.

I looked again and although the switch itself is identical, the wire isn’t coiled like the Sofirn version. But I’d prefer no coiling actually as it gets in the way of things.

Good find JaredM! I’ll see what they say.

ZappaMan

Quadrupel
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Made some prototype . Led directly connected to switch. Full DD power output for 4min , latter starts to drop and in 30sec goes off at Vin 2.8V, at 3V – moonlight, at 4V – 1A. So its like batt indicator and LVP ;)) To recharge you need to turn off for second or few . It works like 1 mode DD. Main driver is unnecessary ;))

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https://www.aliexpress.com/item/1005002531487215.html

Found the switch sold separately. Not cheap, but comes with a mount.

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So I got my parts in today. Don’t yet have the PCBs so I ‘air wired’ everything. First run with a 1500mah cell @ 3.7V starting lasted 13 minutes before hitting the LVP flash. Retesting with charged cell but thinking something in the 15min is going to be where it lands. I started with a 4.7Mohm gate resistor and the turn off response is just slow enough to cause mode switching to be effected ( off time needs to be a few hundred ms longer than normal ). I’m going to try doubling them up and seeing how 2.35Mohm behaves.

Important note: the 22mm four mode sst40 Convoy driver that I received a few weeks ago works without any additional modification.

EDIT: 2.35Mohm works perfect. Starting the runtime test, but it should be right around 6-7 min.

Zappaman
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Good News! I hope the ramping driver used in the C8+ and L21B also come ready to use. But good to know what will be needed if not. Excellent work JaredM! Thumbs Up

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JaredM
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So the runtime is going to depend on the output level and when it hits LVP on the driver it seems. Since as the capacitor drains, the Vgs decays. Rds-on then climbs an exponential curve as Vcap approaches G-S threshold voltage. On mode 2 of 4 the setup ran over an hour before I cut it short. On mode 4 of 4 (~6A) it ran about 3.5 min. Mode 3 = ~4min. I feel like there is going to be dependencies on the Vf of the emitter too, so I’ll test something high (was using LH351D).

Zappaman
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I get some may want longer run-times, but for use on a gun pig hunting (with my hunters and I the last two years), we never run the gun light more than 30-45 seconds at a time when making the kill shots.

When hunting on the move— the usual run time is a few seconds- every five minutes or so to check the field as we move forward to new areas. So about 10-15 times a night (for 1-2 seconds) if stalking for a few miles in woods. But we mostly sit and wait (with night vision) for most hunts and then we only use the gun light to make the kill(s). They are a LOT cheaper than thermal scopes Cash

In any case, when we see a pig the gun turns on and the first bullet is flying 2-5 seconds later- with several shots also sometimes made after that (going after pig #2 and maybe pig #3 if they don’t bug-out too fast). But the party is usually over in under a minute (coyotes are usually one-and-done (10 seconds).

We use hand-held lights for longer views if we need longer light run times (and we often stalk with red lights in the hand, or moonlight also works great if you have it).

So in my use: if this driver can stay on for about a minute with the C8+ and L21B, that is long enough for me. Any longer is “gravy” time Big Smile

The C8+ CULPM1.TG light runs at 8A (full output) and IIRC the L21B also does 8A at full power (Funtanstic may correct me, while I’m also not sure it’s the same driver/output as the older/heavier L21A).

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luminarium iaculator
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JaredM wrote:
So I got my parts in today. Don’t yet have the PCBs so I ‘air wired’ everything. First run with a 1500mah cell @ 3.7V starting lasted 13 minutes before hitting the LVP flash. Retesting with charged cell but thinking something in the 15min is going to be where it lands. I started with a 4.7Mohm gate resistor and the turn off response is just slow enough to cause mode switching to be effected ( off time needs to be a few hundred ms longer than normal ). I’m going to try doubling them up and seeing how 2.35Mohm behaves.

Important note: the 22mm four mode sst40 Convoy driver that I received a few weeks ago works without any additional modification.

EDIT: 2.35Mohm works perfect. Starting the runtime test, but it should be right around 6-7 min.

JaredM wrote:
A bleeder resistor is needed on the driver. It’s the same concept as using a lighted tail switch.

JaredM if someone needs to modify the driver in order to make the switch work please show us where we would have to add bleeder resistor on the driver?
Not anyone here will be happy to modd their driver in order to make working FET switch… Especially if it is complicated.

I thought it could act like plug and play switch and work without any modifications on the driver? Lexel battery powered fet switch did not required any modification on the driver.

thefreeman
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The power has to come from somewhere, a coin cell in the case of lexel’s solution, or the light cell itself through a ”bleeder” resistor connected between Bat+ spring and Bat- ring. On some drivers this can affect mode selection unfortunately.

If you want something universally compatible with no modifications needed then the coin cell is the better solution, with a high pulldown resistor value it will last a very long time before needing to replace the cell.

luminarium iaculator
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thefreeman wrote:
The power has to come from somewhere, a coin cell in the case of lexel’s solution, or the light cell itself through a ”bleeder” resistor connected between Bat+ spring and Bat- ring. On some drivers this can affect mode selection unfortunately.

If you want something universally compatible with no modifications needed then the coin cell is the better solution, with a high pulldown resistor value it will last a very long time before needing to replace the cell.

“On some drivers this can affect mode selection unfortunately”

I have Lexel battery FET switch and my old type of driver lost no memory effect and went to next mode memory…
But I use different single mode driver so mode changing is a matter of past for me. But anyway it would be nice that this works for people that still use multimode drivers

If soldering bleeder resistor to driver is easy like this it should not be big deal in soldering that resistor.

Couple of pictures explains better than thousands of words…

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luminarium iaculator wrote:
thefreeman wrote:
The power has to come from somewhere, a coin cell in the case of lexel’s solution, or the light cell itself through a ”bleeder” resistor connected between Bat+ spring and Bat- ring. On some drivers this can affect mode selection unfortunately.

If you want something universally compatible with no modifications needed then the coin cell is the better solution, with a high pulldown resistor value it will last a very long time before needing to replace the cell.

“On some drivers this can affect mode selection unfortunately”

I have Lexel battery FET switch and my old type of driver lost no memory effect and went to next mode memory…
But I use different single mode driver so mode changing is a matter of past for me. But anyway it would be nice that this works for people that still use multimode drivers

If soldering bleeder resistor to driver is easy like this it should not be big deal in soldering that resistor.

Couple of pictures explains better than thousands of words…

That picture is a valid example of a bleeder mod. On some drivers that may be the best spot, but others maybe not. The only rule is a resistor goes between Bat+ and gnd. Very simple.

I’m not going to buy every driver in the world and test it with this switch. It’s made for modders, so while I will do my best to guide people and answer questions as I always do, I’m not making any promises. For the members buying these in qty to resell, it is ultimately on them to do the R&D to validate what they make and sell. This is a hobby for me, not a business. I do things for fun and for helping out the community, but I have limitations. I’ve already been pretty generous I feel and offered to test a handful of go-to drivers if someone sends me one. Also, my offer still stands for people to pay shipping on the Beta run of boards to test against their products. If you are interested in that PM me. PCBs should show up this week and I could have them out next day.

Quadrupel
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1 Mode Real Direct Drive 17mm Blank Driver with bleeding resistor ;))))
Order from OSH Park
Have made PCB panel for cheaper production and convenient use with stencil.
111

luminarium iaculator
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JaredM,

I now understand that bleeder mod on driver… Piece of cake Davie I think that it is not big deal for personal mods or if someone starts with flashlight sale from 0.

But it is big deal and problem if someone who already sold lets say 200 of lights on market and now he wants to offer special version of FET switch because that switch won’t work with that lights because previous versions of lights don’t have bleeder resistor modd on drivers. Hat

My testing would not be relevant to BLF members because I have market unavailable single mode FET drivers made for me by Led4power.

The best test would be on generic type of drivers(Simon, Mountain Electronics, Kaidomain, etc) that most guys use here.

luminarium iaculator
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Quadrupel wrote:
Fake Driver to use with tail cap switch. Real 1 mode Direct Drive. Order from OSH Park Have made PCB panel for cheaper production and convenient use with stencil. 111

Looking good… Thumbs Up Beer Maybe you guys could also offer version of switch without bleeder resistor modd on driver? If only solution is battery powered than I am pretty sure there would be great interest for such versions too.

But of course this FET capacitor switch with driver bleeder resistor modd is much better solution for someone who does personal flashlight modd or if he is starting flashlight business from scratch…

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So JaredM… wassup’ with the PCB parts?

ZappaMan

JaredM
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Some personal life events taking me out of the spirit. I have received the boards and parts, built one by hand, tested it. Performs as I was describing earlier in this thread. Mosfet capacitance being high is keeping the gate resister in the low single digit megaohms, therefore restricting constant on time with multimode builds. The lower the Vf of the LED the better it seems. Overall it does what it’s supposed to do.

I’ll look into bringing this back online later this week.

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Ah, I was still waiting on a price for tracked shipping to NZ for a beta switch on post #11. Definitely can’t commit to 100pcs without first testing whether it’ll work, can’t have modes messing up

Texas Ace Lumen Tube calibrated with maukka lights

New Zealand store – https://www.piercingthedarkness.co.nz (NZ customers only)

YouTube channel – https://www.youtube.com/channel/UCIUWi2vYp4CWrRkOJM70t_w/videos (Demos for my customers, and reviews)

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Zappaman wrote:
The C8+ CULPM1.TG light runs at 8A (full output) and IIRC the L21B also does 8A at full power (Funtanstic may correct me, while I’m also not sure it’s the same driver/output as the older/heavier L21A).

That L21B’s focus is terrible. Simon mentioned he wasn’t happy with it, but man this sucks. I had to alter the focus and lift the reflector up higher, now it’s very decent. I have now noticed that the L21A’s focus isn’t optimal either.

You’ll need to mod the driver on both the L21A and B since there’s no positive spring. You could end up denting the battery and damaging the driver from the recoil

Texas Ace Lumen Tube calibrated with maukka lights

New Zealand store – https://www.piercingthedarkness.co.nz (NZ customers only)

YouTube channel – https://www.youtube.com/channel/UCIUWi2vYp4CWrRkOJM70t_w/videos (Demos for my customers, and reviews)

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Interested in 10pcs 17mm
Built or DIY – if available I would buy soldered, but I can do it myself if needed.

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Zappaman
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Funtastic wrote:

That L21B’s focus is terrible. Simon mentioned he wasn’t happy with it, but man this sucks. I had to alter the focus and lift the reflector up higher, now it’s very decent.

Please let me know how you fixed the L21b. I agree it’s not right (and Simon also explained he’s not exactly happy with it as well). I have four I need to “get right” Wink Thanks for any advice on this Funtastic! Beer

ZappaMan

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