comfychair-inspired quick+cheap+lazy single-sided 17DD FET-driver (poor man's nanjg92)

Nope, don’t know anything about that…

But I experimented a bit further with the xintd-x3 firmware and I think I have solved my problem.
By changing the input at the following fields: define PWM_PIN, define ALT_PWM_PIN, define PWM_LVL, ALT_PWM_LVL. By swapping the pb0 & pb1 and again swapping OCR0A & OCR0B

Most all of our BLF firmwares require optimization settings for size.

Its a preference setting in atmel studio that effects how the code compiles. I don’t know enough to know what it actually does or explain it, just enough to know what to set it to…

Oke I will look into it. But for my regular Nanjg 105C drivers I still use the luxdrv (really easy to personalize and has everything I need).

Is it normal I only get 3,4 amps on the max setting? I used the PH4030AL FET in combination with a Sony / Murata Konion US18650VTC6 3120mAh - 30A cell. With cheap cells I only get 2,2 amp…
Also replaced the leads with some ticker ones, without any effect. Wil try a spring bypass just to be sure.

Thread resurrection needed…

Djozz and other fellow members who may know this…

Is there any way to restrict current draw to not more than 5A in mentioned diy FET driver?

No, not if you want a 5A current limit regardless of led voltage or battery type/charge state. You could add a resistor in the circuit (maybe in the form of thinner longer ledwires) but that would limit current at all modes, not just over 5A, it does not regulate.

What you hope for is current regulation and that is what the original 7135 chips on the original AK-47 driver did (3 chips for 1.05A), and for 5A you need 14 of them :open_mouth: . Similar current regulator chips that regulate more than 350mA do not exist (maybe because of overheat problems in such a small sot23 package) or are not suitable in this application.

The way to go for you may be using a different type of FET’s that can regulate the current instead of just switch on and off. Led4power’s drivers are like that but are not as cheap as these NANJG drivers. A relatively new solution that you may check out are the 5A Convoy drivers, 1.12€ 83% OFF|17Mm Driver Voor SST40 ,4 Modi 0.1% 3% 30% 100%, max Huidige Output 5000mA, Temperatuur Bescherming Management Binnen|Zaklampen| - AliExpress , they are 17mm, regulated at 5A, have 4 simple modes and memory, and have lightweight low profile components that just may survive rifle recoil pretty well. And they are cheap, 5 drivers for 16 dollar.

Thanks Djozz,

I really hoped there is a way to restrict current on this driver for certain applications like OSRAM leds cause I have hundreds of them(ak47c1) and since they have proper mode order for mine application(c1 firmware, it always starts on high mode).

While thinner wires are not suitable for mine build Resistor in a circuit sounds good but I really don’t know where to place them and what resistors should I buy? I hoped you could show that? :wink:
With FET drivers we use high current cells like INR30Q so this Djozz FET driver should be modded so it can’t pull more than 5A of current in a setup with INR30Q and Osram WF emitter. Probably with proper resistor this is doable?

Convoy drivers unfortunately does not have suitable mode order for hunting purpose low>high. And I really don’t need regulation for 1x18650 cell setup. Short burst of turbo is all I need.

For guns / rifles you need a fat rubber or even plastic ring around the battery spring, as a bump stop, like in car suspension (for the same reason)
It will prevent spring crush and PCB impact.

Yes, luminarium iaculator, get that driver from Simon, for Pete’s sake. :wink:
Doesn’t it have mode memory?

Simple spring bypass with 18AWG wire acts like a bump stop and perfectly presses flat top battery to Djozz FET driver spring(which is also bypassed with 22awg wire). Holds heavy centerfire magnum recoil without any issues.

I would order from Simon but I don’t like mode order.

And I still hope that there is some kind of resistor that can be added to this Djozz FET driver which would restrict current draw to not more than 5A with INR 30Q and OSram WF

Doesn’t it have mode memory?

A tough rubber ring around the spring moves the force from the center of the driver PCB to the rim, so it won’t bend or break.
It’s a simple mod.
You can cut a ring from rubber hose, or even garden hose or something similar.
It will also reduce the impact on the battery itself.

Thanks for rubber ring idea but in mine mode there is no impact on battery at all… Once when you put the bat it stays firmly in place.
During few years I done hundreds of them without any issue. No need for rubber :), although we really do know that proper rubber is really needed for certain applications :beer:

I saw Djozz you mention recoil hunting, so i thought you used lights on rifles.

(edited)

Jerommel,
Magnum centerfires are rifles. Magnum means badass rifles :laughing:
Lets stick to my primary task on this thread. Maybe you could help?

Do you know what resistor should I buy and where should I place it in a circuit of this Djozz FET driver? Pretty please?

Edit: Simon drivers has mode memory and is OFF time based which I don’t prefer. Old grandpa hunters likes simplicity and any kind of complicated UI is out of a question.

Oh, i see.
We here in EU only have cutlery for weapons, so i’m not familiar with gun / rifle lingo.

You mean it will change modes when you use it again within seconds, i guess.
No, i wouldn’t know what value resistor you would need.
Also, i assume you want to use the 1mm² white flat?
You should know it’s not worth driving it on 5 Amperes.
It maxes out on 4.5 Amperes and the difference between 4.0 and 4.5 Amperes is quite negligible.

I see 2 possibilities to best solve your question:

1] Don’t use fully charged cells, and forget about resistors and thin wires and crappy springs and what not.
You’ll have much more maximum output runtime when you start with 3.8 Volts cells, the discharge curve of the battery is much less steep under 3.8 Volts.

2] Get a Nanjg driver with 8x 7135 and the four stars to choose groups, and stack 3 or 4 more 7135 on top of the original 7135’s.
It’s not that hard if you have a fine soldering tip and some flux grease.
The trick is to
a) remove the middle leg
b) bend down the 2 legs
c) stick them on top of the original 7135’s with a tiny drop of super glue
(the bent down legs will help positioning them, but you can also first glue them in place and then bend down the legs, but then the glue may break loose))
d) solder bridge them to the 2 outer legs of the originals
e) bend down the thermal tab (which is also the middle leg)
f) solder thermal tab to the original’s thermal tab

The second possibility gives you safely regulated current for a considerable time.
Use fairly high drain cells (30T or VTC6 or similar) and optimize the electrical path to prolong regulated current drive.
You eliminate many unknown / inconsistent variables with 11 or 12x 7135.
You will never over drive the LED.

(I assume you don’t use a remote switch, with long thin wires.)

Jerommel,

Thanks on a help but please tell me something I don’t know! :person_facepalming: :slight_smile:
I have asked you simple question: “Do you know what resistor should I buy and where should I place it in a circuit of this Djozz FET driver?” If you know ok if you don’t know that is also fine… That was the question that demanded answer. It is ok if you don’t know that :innocent:

I sold over 1000 modded lights in mine life. I have a master degree on soldering AMC 7135 and 7138 chips to linear drivers and you really don’t need to cut middle leg. I solder all 3 of them even without bending.
I know what are my potential solutions but I refuse them since I have hundreds of AK 47 C1 drivers and if there is possibility for current restriction than I will try to mod them.

It is the most stupid thing to stack so many amc chips on small linear drivers cause it heats a lot and failure will obviously happen sooner or later. FET driver is much much better than any high current 17mm linear driver with hundreds of stacked 7135 chips cause it does not heat that much at all…

I also know how FET drivers work since I made hundreds of them this diy Djozz type and Texas ace one (without stencil; just soldering iron and calm hand).

If you want to run FET with Osram WF just use low current 18650 cell at any charge state and don’t bypass springs and that is it. Or add thick steel contact springs for example.

But this is not solution for the problem of how to restrict current in FET driver.

Potential solution in this below mention style but I would like to take that to higher level and make restriction on driver only… EasyB!

So any advice regarding my question should led to solution(or possible solution) how we can simply restrict current draw in our FET drivers? Simple resistor mod or something else? It is probably doable but we need electronic engineer for this.

:beer:

Maybe youŕe not the only reader here.

Demand…
I gave you the answer to that particular question:
I don’t know what value you need (but i could calculate it if i look up the specs / test results), and it also depends on the battery you use, the health of the battery, how well the contact between battery and springs is, the condition of the switch you use, the ambient temperature, differences between individual LEDs, LED wires.
All uncertain variables.
Oh and of course the charge of the battery…

So they stand upright then, and have no decent thermal path to the driver.

Okay, i didn’t realize you’ve got hundreds of those 3x 7135 drivers.
I can understand you’re not planning to stack those up to 12x 7135.

It depends on how much work you put into it.
at 4.1 Volts (freshly charged with 0.1 Volts battery sag) it’s less than 1 Volt x 4.5 Amperes, is a maximum of around 4 Watts of heat the driver has to dissipate. With the thermal tabs soldered together and the driver sits tight with a alu / brass retainer ring in the pill or head, it will survive.

That’s true.
The maximum 4 Watts will be dissipated elsewhere in the electrical path, including inside the battery itself.

But it’s a series chain, so it’s the same as adding a resistor to the driver, but the resistor is approximately the same whether it’s hot or cold.

ok.

“So they stand upright then, and have no decent thermal path to the driver.” Hmmm :question: :slight_smile:

Yes they stand above or “upright” soldered directly on their twin AMC 7135 brother soldered at 4 points: 3 legs and one back soldered so it is the most superior way of stacking 7135 chips with the best thermal path unlike your 2 legged one :laughing:

But lets stay on topic…

Edit:
“But it’s a series chain, so it’s the same as adding a resistor to the driver, but the resistor is approximately the same whether it’s hot or cold.”

When you sell thing to potential buyer you really don’t know which cell he plans to use so you must protect yourself.

Sorry, i don’t understand what you mean by ‘back soldered’ regarding the larger tab.
I can’t visualize what you mean.
Do you solder a piece of copper between the back of the standing one and the larger tab of the surface mounted one?
That would indeed be better than how i do it.
If i had to use the AK47 with 12x 7135 on it, i would give it a thin sheet copper wall around it, also soldering the PCB outer perimeter.
But enough about 7135’s

And sorry number 2 for forgetting who you were.
I’ve been away from here and the flashlight hobby for a while.
But now i remember.
And now that i know you decided to use the drivers you have in stock, i understand.
And yes, i understand your point about buyers.
But frankly that sounds to me like 1 more reason to opt for current regulation…

Single 1x18650 cell configurations(I use 1x18650 configurations only) will have even less runtime on high mode with regulated 5A driver than the one without regulation (FET Driver). Only difference is they are truly in regulation while FET not.
With FET driver (once when modded or just by using lets say Cree XP G2 S4 2B) will pull from 5>3.5A 4.2>3.3V of INR 30Q battery on high mode.
With mentioned drop 5>3.5A 4.2>3.3V LED will not loose much visually on performance and it should have even better runtime than regulated one since at certain point of battery discharge will have less current draw which again like I said visually will not have any drastically visual experience for user… Especially with Osram wf led emitters. I really don’t visually see any difference between 5A draw and 3.5A draw on mine white flat. Only when I put on lux meter I see the difference.

Not to mention that FET driver does not generates heat at all. Build like a tank(especially modded and potted Djozz style Nanjg AK 47 which has thicker PCB than any 17mm driver I ever tried or seen) . Virtually indestructible setup.

The maximum current is dependant on many factors, so a single resistance value can’t be calculated that covers all those factors.
However, if you know the maximum current your driver pulls as it stands, and the voltage across the LED at that current, it should be possible to calculate a value that reduces the current to 5A for this single instance.

As for where the resistor goes, in theory only, you either need to limit the current coming out of the battery(so somewhere between the battery out and FET in) or out of the FET (so somewhere between FET out and LED in) or somewhere in the negative path of the battery, LED or FET, though i’m not sure of the heat implications with regards to the different placements.

Changing the resistance path of the MCU would have no effect on LED current.

I would try using a fet with a higher RDSon. We have always looked for fet’s with a low resistance. If you trying to limit current to 5 amps search thru Digikey for a fet with higher resistance. Some experimenting would have to be done to get the right fet resistance but it could be done for a particular setup.