LD-2 : 6Amps pwm-less linear driver - info and FAQ thread

[prisma]

which resistor value do I need for 12A setting?
Thanks!

[led4power]

It's 76.8K.

[prisma]

I thought 76.8k would be for 9A. I want to go for 12A

[led4power]

Equation for max. current set resistor is:

R_set[kOhm]=~900/I_max[A]

So,for example for 6A->150kOhm(default),9A->100kOhm,12A->75kOhm,5A->180kOhm etc...

[Ronin42]

A dumb question, but will the LD-2 work with both forward and backward clicky switches?

Which ones are the standard on/off switched on lights with separate on/off and mode switches?

[led4power]

Good answer from DBCstm to your question:

For sale : LD-2 and LD-M2 driver (Updated)

LD-2 driver info thread: [image] Price: 14.9$/piece Note: NTC resistors (1 per driver) are included by default. Additional DIY parts [image] Moonlight parts 0.25$/set (for one driver) 2xLi-ion("6V") support parts 1.0$/set (for one driver) 3xLi-ion("9V") support parts 1.0$/set (for one driver) 4xLi-ion("12V") support parts 3.5$/set (for one driver) Resistor for 5A,7A,8A,9A,10A or 12A mod 0.1$/piece Equation for max. current set : Rse…

[Ronin42]

Yes but it seems I did not ask the right question.

so

I see I did not clarify my question.

My question is “I have a friend” who has lights that once upon a time had a forward clicky (on/off) + a magnetic ring (mode selection)(that for whatever reason the mode ring along with the driver is/are now dead) so no hope of “factory” modes, Would the LD-2 work?

Or maybe I should ask, other then turning it on and off will the forward clicky (typical on/off only switch) will the LD-2 give me control over modes using the existing tail cap switch?

Thanks again for your help.

And thank you for the follow up.

[Mikk0]

As HKJ tested, LD-2 produces over 7W of heat with MT-G2 at 9A. Does it survive long term usage with MTG2/XHP at 6A in open air without cooling (floating inside flashlight head) ?

[led4power]

It strongly depends on batteries used. With low drain,or 18350 batteries,6A shouldn't be a problem,because of larger voltage sag,but putting driver "so it floats inside of flashlight" is not a good idea,max. allowed dissipation in that case is ~1W.

[Mikk0]

@led4power

It strongly depends on batteries used. With low drain,or 18350 batteries,6A should be a problem,because of larger voltage sag,but putting driver “so it floats inside of flashlight” is not a good idea,max. allowed dissipation in that case is ~1W.

Thanks. I know it could be a problem but needed confirmation.

Offtopic: Plan was to use it floating inside Olight SR51.

[vinte77]

What are the dangers of not using the ntc sensor if any?

[led4power]

In that case you don't have protection from flashlight overheating.

[DB_Custom (Dale)]

I’m not really understanding how to use the NTC sensor, is it mounted to the back side of the emitter shelf? Glued down with Arctic Alumina Thermal Adhesive or how? In a copper pill, could it be soldered in? Will full contact with copper (or any metal really) short it out? Never used one before, wondering if it might be soldered to the pill… maybe one side only?

Would it be wise to move it to the walls of the driver cavity to remove it slightly from the direct heat of the emitter, thereby buffering it?

Would the driver benefit from potting it with Arctic Alumina Thermal Adhesive? Maybe more so if it were used in a floating environment? Is there a particular component that creates the heat? The MOSFET or MCU? Could a small heat sink be used to aid heat dispersal from this component, while potting the driver?

Wanting to understand these basics as I got mine in yesterday and am looking forward to putting them to work. :bigsmile:

Thank you for your hard work and dedication, very much appreciated…

[DavidEF]

@DBCstm

I’m not really understanding how to use the NTC sensor, is it mounted to the back side of the emitter shelf? Glued down with Arctic Alumina Thermal Adhesive or how? In a copper pill, could it be soldered in? Will full contact with copper (or any metal really) short it out? Never used one before, wondering if it might be soldered to the pill… maybe one side only?

Would it be wise to move it to the walls of the driver cavity to remove it slightly from the direct heat of the emitter, thereby buffering it?

Would the driver benefit from potting it with Arctic Alumina Thermal Adhesive? Maybe more so if it were used in a floating environment? Is there a particular component that creates the heat? The MOSFET or MCU? Could a small heat sink be used to aid heat dispersal from this component, while potting the driver?

Wanting to understand these basics as I got mine in yesterday and am looking forward to putting them to work. :bigsmile:

Thank you for your hard work and dedication, very much appreciated…

Dale, here a few things I just clipped from djozz’s review/test of the prototype drivers, linked in the OP of this thread. This should help answer some of your questions. For more information, I recommend you read both of the test threads (djozz and HKJ) in their entirety.

@djozz

“As the LD-1, the LD-2 is a 17mm diameter lineair flashlight driver made by BLF-member led4power, that is current-regulated at all modes (so no PWM) by controlling the current throughput of a FET. So any overvoltage not required for obtaining a desired current is burned off by the FET, which at times will dissipate a fair amount of heat.”

“apart from a heat protection on the driver board, there is an option for a remote heat protection using a NTC-thermistor that can be glued to the pill or ledboard: an output stepdown is only happening when overtemperature is actually detected.”

“I did a brief test to see if the remote temperature sensing worked. For that, as instructed, I glued a small thermistor (came with the prototype board) to the surface to be measured, in this case an old aluminium ledboard with an XM-L emitter, and connected that to the driver. I ran the driver on high setting on a 18650 IMR cell while pointing the led towards a luxmeter, and this is what happened:

https://www.youtube.com/watch?v=eXw9MobI6xM&feature=player_embedded

Nicely, a stepdown to medium happened when the ledboard got too hot. Even further stepdown followed when even medium setting was too high (as this bare board has no heatsink whatsoever), then as the temperature went down again, the led output went up again. Well done! In an actual flashlight all this will be slower of course as there is actual heatsinking present then. But I’m quite impressed that this set-up actually saved the old XM-L led on a non-DTP aluminium board floating in air!”

Edit: By the way, the NTC is an SMD component and I’ve seen some MCPCB’s made with a place for a NTC to be soldered on. But it probably shouldn’t be soldered directly onto just bare metal, unless you’re thinking of standing it on one end, with the other end pointing out away from the metal surface.

[DB_Custom (Dale)]

Thanks David, appreciate that effort! Explains a lot

[hank]

What’s the diameter of the thru-holes for the + and - wire?
Or, what gauge of tinned wire will poke successfully through those holes to make a clean connection with the least amount of solder?

[Hell2Pay]

From led4power OP

Completely redesigned PCB with big symmetrical through hole pads for 20AWG LED wires – wires can be very short and mounting driver is now easier than ever! Other smaller pads grouped around LED pads are for NTC external temp. sensor and e-switch connection

[led4power]

Generally,you can use 20AWG unsoldered wire,and probably 22AWG presoldered wire.

[DB_Custom (Dale)]

I must have missed something somewhere… when modifying to 9A with a resistor mod, is the new resistor stacked or does the 6A resistor have to be removed first? These are itty bitty! Removing that one that’s there is scaring me!

I am stuck in a rut, to be sure. I have learned to solder small components with my glasses removed. Today, setting up some of these new LD-2’s with their very small components I got really smart (hahaha, yeah right!) and I set up my Canon 5DMkII with it’s full HD video capability and then hooked it to a 32” TV. The macro lens let me get a massive view of the driver for easy identification of the small pads. Then I went right back to using my naked eyes while all the gear sat unused!

I found time slowed by a factor of almost 5X! What felt like 3 minutes was 15-20 minutes on the clock! Suddenly hours were gone, just soldering moon sets and some 6V sets on 12 of these for Jubuldum. And here I am, wondering how to finish with the last 4 that he want’s to be 9A… leave the 6A resistor and stack, or replace it with the 9A component?

[Rufusbduck]

Pretty sure it’s a replacement rather than stacking.

Easier max. current set – current on LD-2 can be increased or decreased with only one high resistance 0603 resistor change; with a lot of available resistor values, current can be “fine tuned” – much simpler and cheaper compared to shunt resistor change.