Discontinued: LD-M2 - info and FAQ thread (up to 19V 20Amps PWM-less linear driver)

Product is no longer produced.

Sales thread:

Useful links:


LD-M2 is a high power version of LD-2 developed because of continuous demand for higher power drivers which could reliably drive new big emitters like MT-G2,XHP50,XHP70,and multiple XM-L2s,nichia 219C etc.

Idea was old as LD-1,and it's simple:put main source of heat-mosfet on separate board which could then dissipate that heat more easily.Last testing with mosfet on led mcpcb showed good results,much better than older idea of FR-4 with vias : https://budgetlightforum.com/t/-/33706?page=4#comment-809544

Disadvantage of that method is two separate boards,so stacking two boards was pretty logical solution.

LD-M2 has two boards,the bottom one is 1mm aluminum metal core pcb,70um copper,with MOSFET,NTC sensor,moonlight resistor and multicell support parts on it;the top one is basically LD-2 pcb without parts that are on bottom pcb.

Result is driver with identical features/specifications like LD-2 except that voltage,current and power dissipation ratings are higher.

Because of that,I will mention only differences compared to LD-2 specifications (you can find LD-2 full specification in LD-2 info thread):

  • Input voltage: 2.8 - 19V (user must solder jumpers for proper operation,depending on number of cells in series)
  • Output current on high: 6A or 12A, 4A - 20Amps possible by changing 0603 resistor
  • Max. power dissipation: 15Watts@25C case temperature, 12Watts@60C case temperature
  • NTC over temp. sensor,1S-4S cell support parts and moonlight parts are already soldered on MCPCB by default - no need for adding/changing any parts for 1S-4S cell operation,only jumpers soldering/desoldering
  • less than 150uA of parasitic current in sleep mode for all 1S-4S settings (slightly lower than LD-2 with multicell parts)
  • Only two thick and one thin wire is needed for complete connection (optional,two additional thin wires for e-switch)
  • Two big solder pads on MCPCB for up to 16AWG wire support
  • 1mm bottom alu metal core PCB with 70um copper - bottom is electrically isolated so it can be mounted directly on flashlight metal surface
  • 25mm diameter,~5.5mm height

Moonlight resistor note:

Moonlight current set: Rmoon=(Vbatt - Vled)/Imoon

For 2S,3S and 4S configurations moonlight current will be 2,3 or 4 times higher if stock 154Ohm resistor is used! Upper equation is still valid,but because (Vbatt - Vled) is 2,3 or 4 times higher,current is also higher for the same factor.To keep moonlight current at ~10mA in case of 2S,3S and 4S configurations,moonlight resistor should have next values:

1S - R~150 Ohm

2S - R~300 Ohm

3S - R~450Ohm

4S - R~600Ohm

As it can be seen from equation,current depends on battery voltage,so it will drop as battery voltage drops.Typical Vled values for high power white LEDs at very low currents are 2.6-2.7V.

Setting operating voltage: 1S-4S solder jumpers

Driver supports 1 to 4 Li-ion cells in series,and to ensure proper operation,some solder jumpers must be shorted,deepening on cell number:

1xcell (1S) - jumper 1S soldered,others unsoldered

2xcells(2S) - jumper 2S soldered,others unsoldered

3xcells(3S) - jumper 2S and 3S soldered,others unsoldered

4xcells(4S) - jumper 2S, 3S and 4S soldered,others unsoldered

Note: driver comes with all solder jumpers unsoldered,so user must solder jumpers depending on his application.


Driver configured for "N" cell operation should not be used with "N+1" cells!

Driver cannot protect itself from too high voltage,so it will burn if it’s connected to higher number of cells in series in that case.

Connection diagram:

Diagram made by BLF member Andi,thanks!



  • driving single or multiple emitters - XM-L2,XP-l,XP-G2,Nichia 219C,MT-G2,XHP50,XHP70,big color leds like SST-90,etc. in bigger flashlights (well in every flashlight with place for 25mm driver:)


As a first subscriber I hope I can get a sample for (well, I don’t have proper testing equipment so I will say) for my own pleasure :smiley:

great evolution of the LD-2!

Sweet! :wink:


I would love to see it in 22mm, but 25 is useful as well. Now to just get ahold of one!

Looks great, it is a beast. Great work Neven, as always. Count me in for one or two at least.

Put me up for one please!

Is it possible to solder the wire to the LED Anode (+) to the “big hole at 4 o’clock” in the your connection diagram - like with your LD-2 driver?

No, LED anode should be connected directly to contact PCB/spring/Batt+(it would make no sense connecting thick wire to driver and from driver to LED+ with this type of driver,this is just easier).

Nice new developement, I'm not a big flashlight addict, so it is not for me, but I'm sure many others will love this one!

So now that this driver is available for purchase, what are some good host options for this beast? I don’t think I own anything large enough to hold it…yet.

Yes, yes, yes.
This driver is getting my modding juices flowing. I want. I’ll figure out what I’ll do with it later.

One example is SD75:http://www.taschenlampen-forum.de/modding/43906-modding-lumintop-sd75-2.html#post616271

I'll mod SRK soon(3x6A).

Few other lights that come to my mind are Courui D01,TK75,BTU shocker,trustfires TR-J19,J20,Maglites?

Is it? What is the price?

19.99 USD shipped?

hey does this driver have LVP for whatever cell configuration that is chosen? just wondering…