> ## Documentation Index
> Fetch the complete documentation index at: https://dragonwingdocs.qualcomm.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Publish the battery state with qrb_ros_battery
> The qrb_ros_battery sample application is a package that publishes the battery state data from the system node.
The `qrb_ros_battery` package communicates with the battery service through DBus. The battery service gets the current battery status by accessing the sys nodes.
## Pipeline flow for `qrb_ros_battery`
The following figure shows the pipeline flow for `qrb_ros_battery`.
## ROS nodes used in the `qrb_ros_battery` pipeline
The following table lists the ROS nodes used in the `qrb_ros_battery` pipeline and describes what each node does.
| ROS node | Description |
| -------- | -------------------------------------------------------------------- |
| Battery | Publishes the battery information through the `battery_stats` topic. |
## ROS topic used in the `qrb_ros_battery` pipeline
The following table lists the ROS topics used in the `qrb_ros_battery` pipeline, with the message type and a description of each topic.
| ROS topic | Type | Description |
| ---------------- | ---------------------------------- | ------------------------------------------------------------------------------------------ |
| `/battery_stats` | `` | Battery system information, including voltage, temperature, current, charge, and capacity. |
## Prerequisites
You have set up the device, installed ROS2 Jazzy and the Qualcomm Intelligent Robotics (QIR) SDK on the device according to [Install the QIR SDK](./install-the-qir-sdk).
## Run out-of-the-box `qrb_ros_battery`
```bash Run the battery node theme={null}
source /opt/ros/jazzy/setup.bash
ros2 run qrb_ros_battery battery_node
```
```bash List the ROS topics theme={null}
source /opt/ros/jazzy/setup.bash
ros2 topic list
```
```bash Echo the battery topic theme={null}
source /opt/ros/jazzy/setup.bash
ros2 topic echo /battery_stats
```
### Example output
The following figure shows the terminal output of `ros2 topic echo /battery_stats`.
