Discrepancy in battery current sign between gz and ROS 2 for discharging state

[Tacha-S]

Environment

• OS Version: Ubuntu 24.04
• binary build version: 8.6.0

When using a ROS 2 bridge to convert battery state from gz to `sensor_msgs/BatteryState` in ROS 2, `sensor_msgs/BatteryState` expects the `current` to have a negative value during discharge. However, the `gz-sim-linearbatteryplugin-system` plugin does not behave this way. Is it correct for the `current` in the gz message to remain positive even during discharge?

Description

• Expected behavior:

current value is negative value.

• Actual behavior:

current value is positive value.

Steps to reproduce

1. 2. 3.

Output

header:
  stamp:
    sec: 47
    nanosec: 885000000
  frame_id: ''
voltage: 22.915739059448242
temperature: 0.0
current: 21.886171340942383
charge: 1.7268285751342773
capacity: 2.0
design_capacity: .nan
percentage: 86.3414306640625
power_supply_status: 2
power_supply_health: 0
power_supply_technology: 0
present: true
cell_voltage: []
cell_temperature: []
location: ''
serial_number: '