12S integration

  • Is there anyway to integrate VOXL or Flight Core with a 12S battery pack?

    The I2C coming off of the power module is really getting me stuck

  • Dev Team

    Practically speaking, if you can provide Voxl with 5V @ 6amps burst load (~15W quiescent), then you can use any power module/BEC you want (for your motor-ESC combo of course) to J1 (Voxl) or J1013 (Voxl-Flight).
    For a FlightCore alone, you can get away with 5V @ ~1.5A turn-on burst (~400-700mW quiescent, use case dependent) on any connector with "VDCIN_5V_CONN" such as J1, J4, J9, J8, etc.
    Our Power Module does just that with up to 6S support and the I2C based power monitoring.
    Our Voxl/Voxl-Flight and FlightCore products expect that I2C to be at 5V matching the input supply.
    Can you elaborate further on what issue you are having with the I2C port? Are you trying to use it or not use it? I might need to pull in a PX4 expert with some help there if related to SW.

    For background info, ModalAI doesn't do 12S yet unfortunately due to OSHA voltage limits above 50V (12S fully charged LIPO is 50.4V) which require more advanced safety training, extra fire safety equipment, etc. Maybe in the future we will if the demand requires it.


  • @Vinny

    Thank you for your quick reply. My issue is specific to power modules. The max range on the ModalAI power module appears to be 6s. It tells the flight core, voxl2, etc... what voltage and amperage (needed for battery percentage in PX4) is coming from the battery. The power module talks over I2C.

    There are other power modules that can handle 12S, for example pm06 from holybro: here. The issue here is that this power module (from my understanding) sends an analog signal about voltage and current 25a4d2c0-2702-4926-99c0-db519f7f20d0-image.png

    In my head....I was thinking there might be an analog to I2C board or something. Or I could just be out of luck.... maybe integrate some type of small arduino board to do the conversion.

    Posted here before I dove down a rabbit hole

  • @Vinny So the heart of my issue is....PX4 needs to be able to read battery voltage of a 12S battery. If that makes sense

  • Dev Team

    Hi Andrew,
    This is great info, thanks for clarifying.
    Unfortunately, our current product offerings do not support the "Pixhawk" style APM ADC inputs for current and voltage monitoring.
    However, I would bet that you could find source code for an Arduino or STM project where these ADC values have been converted to appropriate PX4 I2C digital formats that you can then feed into our products. Keep in mind, the I2C bus needs to be at 5V and you should provide the I2C pullups on your converter module (anything from 10K to 4.7K works well for our I2C translator).


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