# Voxl2 + M0041 RevB Battery Monitor on Arducopter

Source: https://forum.modalai.com/topic/5117/voxl2-m0041-revb-battery-monitor-on-arducopter
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2026-03-18 20:35:04 UTC by Dan Jennings
Replies: 10 · Views: 769

## Dan Jennings · 2026-03-18 20:35:04 UTC

Hi I'm using the M0041 board to power our voxl2 running ardupilot and having difficulty configuring the battery monitor. I found [this post](https://forum.modalai.com/post/21576) but we do not have the BATT_I2C_BUS parameter to set. 

When checking voxl-inspect-battery, we only get the headers, no data. Voxl-vision-hub is running.

```
voxl-version
────────────────────────────────────────────────────────────────────────────────
system-image: 1.8.04-M0054-14.1a-perf
kernel:       #1 SMP PREEMPT Mon Mar 24 22:31:58 UTC 2025 4.19.125
────────────────────────────────────────────────────────────────────────────────
hw platform:  M0054
mach.var:     1.0.1
SKU:          MCCA-M0054-C11-T0-M0-X0
────────────────────────────────────────────────────────────────────────────────
voxl-suite:   1.5.0
────────────────────────────────────────────────────────────────────────────────
Packages:
Repo:  http://voxl-packages.modalai.com/ ./dists/qrb5165/sdk-1.5/binary-arm64/
Last Updated: 2026-03-18 01:43:20
List:
libfc-sensor                1.0.7
libmodal-cv                 0.5.18
libmodal-exposure           0.1.4
libmodal-journal            0.2.6
libmodal-json               0.4.7
libmodal-pipe               2.13.2
libqrb5165-io               0.5.0
libvoxl-cci-direct          0.3.3
libvoxl-cutils              0.1.5
modalai-slpi                1.2.0
mv-voxl                     0.1-r0
qrb5165-bind                0.1-r0
qrb5165-dfs-server          0.2.0
qrb5165-imu-server          1.1.3
qrb5165-mini-tof-server     0.2.2
qrb5165-rangefinder-server  0.1.5
qrb5165-slpi-test-sig       01-r0
qrb5165-system-tweaks       0.3.6
qrb5165-tflite              2.8.0-2
voxl-ardupilot              4.8.0-325875bb
voxl-bind-spektrum          0.1.1
voxl-camera-calibration     0.6.0
voxl-camera-server          2.2.4
voxl-ceres-solver           2:1.14.0-10
voxl-configurator           1.0.2
voxl-cpu-monitor            0.6.0
voxl-docker-support         1.3.1
voxl-elrs                   0.4.7
voxl-esc                    1.5.4
voxl-feature-tracker        0.5.2
voxl-flow-server            0.3.6
voxl-gphoto2-server         0.0.10
voxl-joystick-server        0.0.6
voxl-jpeg-turbo             2.1.3-7
voxl-lepton-server          1.3.3
voxl-lepton-tracker         0.0.4
voxl-libgphoto2             0.0.4
voxl-libuvc                 1.0.7
voxl-logger                 0.5.3
voxl-mavcam-manager         0.6.0
voxl-mavlink                0.1.5
voxl-mavlink-server         1.4.9
voxl-modem                  1.1.8
voxl-mongoose               7.7.0-2
voxl-mpa-to-ros             0.3.9
voxl-mpa-tools              1.4.0
voxl-open-vins              0.4.19
voxl-open-vins-server       0.3.12
voxl-opencv                 4.5.5-3
voxl-osd                    0.1.8
voxl-portal                 0.7.11
voxl-px4                    1.14.0-2.0.105
voxl-px4-params             0.7.5
voxl-qvio-server            1.2.0
voxl-remote-id              0.0.9
voxl-reset-slpi             0.0.1
voxl-state-estimator        0.0.5
voxl-streamer               0.7.5
voxl-suite                  1.5.0
voxl-tag-detector           0.0.5
voxl-tflite-server          0.4.1
voxl-utils                  1.4.8
voxl-uvc-server             0.1.7
voxl-vision-hub             1.8.23
voxl-vtx                    1.4.7
voxl-wavemux                0.0.1
voxl2-io                    0.0.3
voxl2-system-image          1.8.04-r0
voxl2-wlan                  1.0-r0
```

## Reply by Eric Katzfey (ModalAI staff) · 2026-03-18 21:53:51 UTC

@Dan-Jennings Which arducopter build are you using?

## Reply by Eric Katzfey (ModalAI staff) · 2026-03-18 21:54:47 UTC

@Dan-Jennings Rather than use voxl-inspect-battery have you tried QGC or Mission Planner or Mav Proxy?

## Reply by Dan Jennings · 2026-03-18 23:22:47 UTC (in reply to Eric Katzfey)

@Eric-Katzfey 
We're on voxl-ardupilot 4.8.0-325875bb

I've been connecting through mission planner, but have not been able to get any battery data. Looked through mavlink inspector and there is no battery_status topic.

## Reply by Eric Katzfey (ModalAI staff) · 2026-03-19 17:58:01 UTC (in reply to Dan Jennings)

@Dan-Jennings I'd try our `voxl-inspect-mavlink` application. Check `voxl-inspect-mavlink mavlink_onboard` and `voxl-inspect-mavlink mavlink_to_gcs` and see if `battery_status` appears at all. I just loaded `voxl-ardupilot_ArduCopter_4.8.0-94b27fd3_arm64.deb` on my voxl2 with our standard APM and I see battery status in QGroundControl and with `voxl-inspect-mavlink mavlink_to_gcs`. Also, can you upgrade to VOXL SDK 1.6.x?

## Reply by Dan Jennings · 2026-03-20 21:01:48 UTC (in reply to Eric Katzfey)

@Eric-Katzfey 

I don't see any battery_status message
![2eb6bb40-4283-4e6d-9acb-5d2873af8853-image.png](https://forum.modalai.com/assets/uploads/files/1774040498998-2eb6bb40-4283-4e6d-9acb-5d2873af8853-image.png)

## Reply by Dan Jennings · 2026-03-20 21:02:44 UTC (in reply to Eric Katzfey)

@Eric-Katzfey 
We will look into updating the sdk, but that's always a fair bit of work.

## Reply by Eric Katzfey (ModalAI staff) · 2026-03-23 17:16:47 UTC (in reply to Dan Jennings)

@Dan-Jennings I'm also guessing that the driver may not be detecting the hardware so is not able to get the data for the battery_status. Have you tried swapping some other hardware to see if the problem is associated with a particular unit?

## Reply by Dan Jennings · 2026-04-20 21:04:05 UTC (in reply to Eric Katzfey)

@Eric-Katzfey I finally had an opportunity to try a different power board but we still do not have any battery_status topic. We will look at updating the SDK but don't want to derail our CV development doing so. I'd prefer to find a solution without having to do that.

## Reply by Eric Katzfey (ModalAI staff) · 2026-04-21 15:58:21 UTC (in reply to Dan Jennings)

@Dan-Jennings Honestly, I don't think updating the SDK version will help this issue. But, we highly encourage everyone to be on the latest SDK, regardless, since that's where you'll get the latest fixes and features. And it's how you'll get the best support from us. but in this case I don't think a newer SDK will get you the battery_status. It's probably a hardware issue or a parameter issue. You swapped boards and that didn't help. What about the cable? Those 4 wire cables are notoriously fragile. Can you swap it out and see if that helps? The other item is parameters. You saw that other post about setting BATT_MONITOR to 21 and BATT_I2C_BUS to 1. If you don't see the BATT_I2C_BUS parameter then it must mean that BATT_MONITOR hasn't been set to 21. Make sure it is set to 21, then reboot, then you should see the BATT_I2C_BUS parameter. Then set it to 1, reboot, then you should see correct battery_status.

## Reply by Dan Jennings · 2026-05-19 21:13:41 UTC (in reply to Eric Katzfey)

@Eric-Katzfey 
I'm not sure what may have changed, before when setting BATT_MONITOR to 21 the param would write but we wouldn't get the additional parameters that that setting should have enabled. Last week I tried it again to reply to your last message and we got the BATT_I2C_BUS parameter and were able to get it all working. Gotta love when things seem to magically fix themselves, thanks for the support.

PS, we have built a parallel system on the latest SDK and will be migrating the current one over to match.