# Battery information "N/A"

Source: https://forum.modalai.com/topic/608/battery-information-n-a
Category: ESCs, Sensors and Accessories (https://forum.modalai.com/category/15/escs-sensors-and-accessories)
Tags: power-module
Posted: 2021-12-14 01:27:05 UTC by jbruell94
Replies: 3 · Views: 1868

## jbruell94 · 2021-12-14 01:27:05 UTC

Hello,

I recently purchased a Power Module v3 for a VOXL CAM. When I run "voxl-inspect-battery" I get N/A. This is also received on the web GUI and QGroundControl. I need to have this function working to fly the drone.

To debug I've done the following steps:

1. Used the command "voxl-i2c scan 8 400000" to see if the VOXL CAM can read any I2C devices on the power port. None showed up. I tested the command on the port with the barometric pressure sensor and the scanner is working properly as it found the device.

2. I then used a hardware I2C scanner I have and plugged it into the Power Module v3, and it was able to discover the devices at 0x44 and 0x45. The power module appears to be functioning correctly.

3. I wired a oscilloscope to the output of the VOXL CAM to scan the I2C port and verify the wiring and that the VOXL CAM is sending read commands. I was able to see the commands being sent and that the system is wired correctly.

What can I do to properly setup this module? Is there anything I might be missing?

Thank you,

Justin

## Reply by modaltb (ModalAI staff) · 2021-12-14 18:18:37 UTC

Hi @jbruell94 ,

The I2C bus used to talk to the Power Module v3 is actually connected to the STM32F7 microcontroller (not the snapdragon) so none of the voxl-* tools are really applicable.

Here's the PX4 driver (and as I'm writing this, yes it's a bit confusing since I called the driver in PX4 "voxlpm"....):
https://github.com/PX4/PX4-Autopilot/tree/master/src/drivers/power_monitor/voxlpm

The action starts here:
https://github.com/PX4/PX4-Autopilot/blob/master/boards/modalai/fc-v1/init/rc.board_sensors#L9

The [cable](https://docs.modalai.com/cable-datasheets/#mcbl-00011)  from the APM splits and plugs into [this](https://docs.modalai.com/flight-core-datasheets-connectors/#j6---voxl-power-management-input--expansion) connector on the Flight Core mentioned above.

Let me know if this doesn't help get you going.

## Reply by modaltb (ModalAI staff) · 2021-12-14 18:19:19 UTC

Note: ^^ none of that coding info above is needed, just for reference.  The firmware on the FlightCore portion of VOXLCAM should be ready to go with nothing needed...

## Reply by jbruell94 · 2021-12-15 00:32:08 UTC

Hi ModalTB,

I was able to resolve the issue looking deeper into QGroundControl. I had set the system to HITL after following your awesome tutorial:
https://www.youtube.com/watch?v=-uoIxAkiYtk

To fix this, I switched the system back to "Generic Quadcopter" in order to receive battery data.

Thank you for your through response. It helped me to resolve this.

Best Regards,

Justin