# Can not run rostopic battery state

**URL:** <https://forum.ubiquityrobotics.com/t/can-not-run-rostopic-battery-state/979>\
**Category:** Uncategorized\
**Created:** [June 29, 2022, 7:01am UTC](https://forum.ubiquityrobotics.com/t/can-not-run-rostopic-battery-state/979 "2022-06-29T07:01:38Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![dysqrencia](https://forum.ubiquityrobotics.com/letter_avatar_proxy/v4/letter/d/cc9497/32.png) [@dysqrencia](https://forum.ubiquityrobotics.com/u/dysqrencia)\
**Post date:** [June 29, 2022, 7:01am UTC](https://forum.ubiquityrobotics.com/t/can-not-run-rostopic-battery-state/979/1 "2022-06-29T07:01:39Z")

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I tried running **rosrun teleop\_twist\_keyboard teleop\_twist\_keyboard.py** command to move magni but it says “Waiting for subscriber to connect to /cmd\_vel”. And then, I saw someone had the same problem as me and the comment said to check the battery state, so I tried **rostopic echo /battery\_state** to see my battery status but nothing show up. Can anybody please help me ?

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**Author:** ![MoffKalast](https://forum.ubiquityrobotics.com/user_avatar/forum.ubiquityrobotics.com/moffkalast/32/214_2.png) [@MoffKalast](https://forum.ubiquityrobotics.com/u/MoffKalast)\
**Post date:** [June 29, 2022, 9:27am UTC](https://forum.ubiquityrobotics.com/t/can-not-run-rostopic-battery-state/979/2 "2022-06-29T09:27:21Z")

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Hmm, are you running the commands through SSH on the robot, or is the robot connected to the workstation and you’re running nodes remotely on that?

If through SSH, then the motor node is likely either not running (check `rosnode list | grep motor`) or not establishing serial with the MCB (check `rostopic echo /diagnostics_agg` if there’s `Firmware not reporting its version` being printed a lot). If you get the first one you can try `rosnode kill -a` and then `roslaunch magni_bringup base.launch` to restart it (and you should be able to see any errors on screen when it runs), the second one might require a [firmware update](https://learn.ubiquityrobotics.com/noetic_magnisilver_mcb_upgrade).

If you’re running on the workstation then it may be a networking issue, since ROS often connects in this odd way where topics and nodes are listed but no data is sent to topics. Usually [sorting out /etc/hosts](http://www.faqs.org/docs/securing/chap9sec95.html) on the workstation solves that.

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**Author:** ![mjstn2011](https://forum.ubiquityrobotics.com/user_avatar/forum.ubiquityrobotics.com/mjstn2011/32/30_2.png) [@mjstn2011](https://forum.ubiquityrobotics.com/u/mjstn2011)\
**Post date:** [July 16, 2022, 8:18am UTC](https://forum.ubiquityrobotics.com/t/can-not-run-rostopic-battery-state/979/3 "2022-07-16T08:18:32Z")

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Please write an email to [support@ubiquityrobotics.com](mailto:support@ubiquityrobotics.com) and in the subject say perhaps ‘Cannot control my Magni using teleop\_twist’. State in the email to have this issue brought to the attention of mark Johnston (me) please.