This circuit turns an AC-CDI into a DC-CDI.

An AC-CDI needs a working STATOR to charge. If the stator fails, let it be rewind or buy a new one is pretty expensive!
This circuit was designed to bypass the faulty stator by making High Voltage (around 100 to 200V) directly from the +12v battery.

When the internal SCR of the AC-CDI has been latched in ON state for a spark, only the voltage crossing a falling zero will turn it OFF again. In order to let the SCR return to blocking state, this circuit alternates ON and OFF states.

  • 50 to 20,000 RPM
  • Kill switch
  • Power supply voltage DC 12 volts
  • Current drain: 60mA to 1.3A
  • 2A Fuse Protection
  • Common ground between 12Vdc and HV
  • Dimensions: 75 x 50 x 25mm (3 x 2 x 1 inch)
  • Available Ready to use in the SHOP section.
  • or as separated parts: PCB plus Firmware

Wiring to an ACCDI

FRQ solder pad:
If open (default): Frequency of the circuit is 1000Hz (equal to 6 pulses/rotation at 10000RPM)
If close: Frequency of the circuit is 500Hz (equal to 3 pulses/rotation at 10000RPM)

PWM solder pad:
If open(default): HV generator alternate ON/OFF period at 50% (Maximum output voltage = +220Vdc)
If close: HV generator alternate ON/OFF period at 33% (Maximum output voltage = +140Vdc)

Kill switch:
Remove the KILL wire from the ACCDI and connect the Kill Switch to this Power module
If Kill input is connected to Ground: DC generator stops and Led turns ON.

Over Voltage Protection: Turn the trimmer to adjust the maximum output voltage from +100v until +220v.
Led turns ON when OVP (aka regulation) is active.

Transistors need heatsinks if this unit run at 15000rpm longer then 1 minute.

Blue: Mosfet Gate. Yellow: DC output


Click here for more info




  • Version V1R2C1:
    • First Version.
  • Version V2R0C0:
    • [soft] Improvements.
  • Version V2R0C1:
    • [hard] Change PCB layout.
  • [soft] 2 PWM DutyCycles.

6 thoughts on “AC-CDI 2 DC-CDI”

  1. Hi Thierry
    Sorry to write you again but I just saw that you are doing something similar to what I asked you in the previous email AC CDI 2DC CDI and I see that you do not have it for sale yet but you could send me the program and the PCB to go doing tests.
    Thanks Jose Luis

  2. Hi
    I recently bought this cirquit board
    but there is no wiring diagram anywhere in the letter or on this site.
    How do I connect the AC-DC board to the AC-DC CDI v2,5?
    Please include a wiring diagram to the products you sell please.
    Also, there is no way to contact you in another way than this forum

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