46mm - SRK V2 FET + 7135 Driver DIY Parts Kit

Product Code: SRKFETV2-DIY
Availability: 19
Price: $5.05

2 or more $4.85

Available Options

* SRK V2 Firmware:

* SRK V2 FW Stepdown:

* SRK V2 Input Voltage:

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This is the parts kit for the 46mm SRK FET V2 PCB (PCB sold separately).

This version adds more LED pads, a 7135 option for lower moonlight mode (STAR firmware only), an LDO voltage regulator option for 2S or 3S cell use, support for an external temperature sensor (STAR firmware only) and much more.

This driver will give you near-direct-drive performance in a drop-in package.   Because of the high output potential, this driver should probably not be used with most aluminum MCPCBs, unless it is a light with a lot of emitters.  Check out the current regulated 7135 based SRK driver instead for use with stock or aluminum MCPCBs.

The driver features tabs that will need to be filed down to achieve a tight fit in your host light of choice.  They are necessary due to the slightly different tolerances that exist in these lights. 

Component Locations:

Firmware Options:

There are three great firmware options for this driver:

1. STAR Momentary - No External Temperature Sensor

This firmware provides a simple, yet powerful, user interface.  Starting from off, or any other mode, a short click moves the modes forwards, while a long press moves the modes backwards.  This means that you can start in either the highest, or lowest, mode with either a short click or long press, and then move up or down through the modes at any time.  This firmware also offers an ultra-low moonlight mode, thanks to the secondary output 7135 (1S and 2S only). 

With this option there is also the option for a turbo timer.  The turbo timer will step the light down from the highest level to the next lowest mode at a preset time.  Here are the turbo timer options (STAR Firmware, no temperature sensor only):

  • 30 Seconds
  • 60 Seconds
  • 90 Seconds
  • 120 Seconds
  • 180 Seconds
  • 240 Seconds
  • 360 Seconds

STAR Momentary Mode Options:

  • a. "SRK Special"
    • 7 visually well spaced modes ranging from moonlight to all-out-power
  • b. "Simple"
    • 3 modes: moonlight - 33% - 100%
  • c. "Custom"
    • Choose your own modes.  Here are the options (please enter in checkout comments):
      • Number of modes: Between 1 and 7
      • Mode levels: For example: Moonlight - 5% - 33% - 100%

2. STAR Momentary - External Temperature Sensor

Same user interface and mode level selections as above, but with an external temperature sensor included which steps down modes as the light heats up.  The temperature sensor is set to around 60 degrees celcius, which is about as hot as you typically want a flashlight body to get without burning the user.  It can be affixed to your desired location with an epoxy such as Arctic Alumina or JB Weld (Arctic Alumina is much easier to remove in the future if desired).

The external temperature sensor wiring is as follows:

With pins oriented down, at the 6 o'clock position

  • Left pin: ground (T-)
  • Middle pin: output (tIN)
  • Right pin: VCC (T+)

2. moppydrv (No 7135 or external temperature sensor option)

moppydrv Multi-Group Electronic Switch Firmware Option

For more information about this firmware, click here. 

Input Voltage / LVP Options:

  • 1S (~3V rampdown)
    • This is used for a single cell, or multiple cells in parallel (4.2v)
    • This is the most common SRK / soupcan light configuration
  • 2S (~6V rampdown)
    • For two cells in series (8.4v)
    • Includes LDO
  • 3S (~9V rampdown)
    • For three cells in series (12.6v)
    • Includes LDO
    • No 7135 Option
  • 4S (~12V rampdown)
    • For four cells in series (16.8v)
    • Includes LDO
    • No 7135 Option


This board was created with the collaboration of many of the great members over at BLF such as Mattaus and comfychair, along with JonnyC with help on the firmware.  Check out this thread for more information.

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