Hi we have configured and calibrated our Voxl FPV ESC 4 in 1 to run our T Motor MN5006 450KV motors but have not been able to get battery monitor working. I've tried all options in /etc/modalai/voxl-px4.config Running voxl-inspect-battery results in NA values in all the fields. There is also no Mavlink message for battery monitor. Edit: this is on a VOXL2 mainboard.

@ restore The FPV ESC power monitor should work just like the Mini 4-in-1 ESC power monitor https://docs.modalai.com/voxl2-mini-offboard-sensors/#power-monitoring

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Configuring battery monitor with FPV ESC

Unsolved General Questions

21 Posts 5 Posters 5.9k Views 2 Watching

A Alex Kushleyev

@restore, thank you for checking.

Let's do another test:

for safety, remove propellers from motors
with px4 disabled, go to /usr/share/modalai/voxl-esc-tools on voxl2
run: ./voxl-esc-spin.py --id 2 --power 0 -- this will send a zero power command to ESC ID 2 (which measures the total current and sends back the battery status message). Motors will not spin. This will also request the battery status and you should see output (if possible you can use the latest voxl-esc tools from dev branch from (https://gitlab.com/voxl-public/voxl-sdk/utilities/voxl-esc/-/tree/dev) since I am not sure which voxl-esc version is installed on your board).

./voxl-esc-spin.py --id 2 --power 0
...
Found voxl-esc tools bin version: 1.6
VOXL Platform: M0054
Detected RB5 Flight, VOXL2 M0054 or M0104!
...
...
	Board      : version 42: ModalAi 4-in-1 ESC (M0138-1)
...
...
[0.017] (2) RPM: 0, PWR: 0, VOLTAGE: 15.612V, TEMPERATURE: 35.87C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.612V, BOARD_CURRENT: -0.232A
[0.034] (2) RPM: 0, PWR: 0, VOLTAGE: 15.609V, TEMPERATURE: 35.88C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.609V, BOARD_CURRENT: -0.200A
[0.060] (2) RPM: 0, PWR: 0, VOLTAGE: 15.610V, TEMPERATURE: 35.86C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.610V, BOARD_CURRENT: -0.248A
[0.080] (2) RPM: 0, PWR: 0, VOLTAGE: 15.618V, TEMPERATURE: 35.85C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.618V, BOARD_CURRENT: -0.224A
[0.095] (2) RPM: 0, PWR: 0, VOLTAGE: 15.612V, TEMPERATURE: 35.87C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.612V, BOARD_CURRENT: -0.272A
[0.120] (2) RPM: 0, PWR: 0, VOLTAGE: 15.608V, TEMPERATURE: 35.90C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.608V, BOARD_CURRENT: -0.240A
[0.134] (2) RPM: 0, PWR: 0, VOLTAGE: 15.612V, TEMPERATURE: 35.92C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.612V, BOARD_CURRENT: -0.264A
[0.160] (2) RPM: 0, PWR: 0, VOLTAGE: 15.613V, TEMPERATURE: 35.90C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.613V, BOARD_CURRENT: -0.248A
[0.174] (2) RPM: 0, PWR: 0, VOLTAGE: 15.608V, TEMPERATURE: 35.92C, CURRENT: 0.000A, BOARD_VOLTAGE: 15.608V, BOARD_CURRENT: -0.168A

note that there are BOARD_VOLTAGE and BOARD_CURRENT printed, which are parsed from the battery status message coming from the ESC ID2. Please note that the current around 0 is not very accurate due to a very large measurement range (showing -0.2A, but the discharge current should really be positive based on our convention).

Alex

restore

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wrote on

#21

@Alex-Kushleyev
Thanks for the help, as I was calibrating the ESCs I did notice those messages, which confused me as to why we weren't able to get that information in PX4. On Monday it suddenly just started working despite my changing nothing. Gotta love when things fix themselves

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