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The Battery service provides access to device battery information, including battery level, charging state, and battery save mode status.

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Usage

Add the Battery service to your page overlay and use its methods to retrieve battery information: 
import flet as ft

async def main(page: ft.Page):
    battery = ft.Battery()
    page.overlay.append(battery)
    
    # Get battery level
    level = await battery.get_battery_level()
    print(f"Battery level: {level}%")
    
    # Get battery state
    state = await battery.get_battery_state()
    print(f"Battery state: {state.value}")
    
    await page.update_async()

ft.app(main)

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Methods

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get_battery_level()

Gets the current battery level as a percentage. 
await battery.get_battery_level() -> Optional[int]
Returns: The battery level in the range 0 to 100, or None when it is unavailable on the current environment. Example: 
level = await battery.get_battery_level()
if level is not None:
    if level < 20:
        print(f"Low battery: {level}%")
    else:
        print(f"Battery level: {level}%")
else:
    print("Battery level unavailable")

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get_battery_state()

Returns the current battery state. 
await battery.get_battery_state() -> BatteryState
Returns: A BatteryState enum value indicating the current state. Example: 
state = await battery.get_battery_state()

if state == ft.BatteryState.CHARGING:
    print("Battery is charging")
elif state == ft.BatteryState.FULL:
    print("Battery is full")
elif state == ft.BatteryState.DISCHARGING:
    print("Battery is discharging")

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is_in_battery_save_mode()

Checks if the device is currently in battery save mode. 
await battery.is_in_battery_save_mode() -> bool
Returns: True if the device is currently in battery save mode, otherwise False. Example: 
if await battery.is_in_battery_save_mode():
    print("Device is in battery save mode")
    # Reduce app functionality to save power
else:
    print("Normal power mode")

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Events

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on_state_change

Called when the battery state changes (charging, discharging, full, etc.). 
battery.on_state_change = handle_state_change
The event handler receives a BatteryStateChangeEvent with:
  • state (BatteryState): Current battery state
Example: 
def handle_state_change(e: ft.BatteryStateChangeEvent):
    if e.state == ft.BatteryState.CHARGING:
        print("Device started charging")
    elif e.state == ft.BatteryState.DISCHARGING:
        print("Device unplugged")
    elif e.state == ft.BatteryState.FULL:
        print("Battery fully charged")

battery.on_state_change = handle_state_change

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Enums

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BatteryState

Enum representing the battery state:
  • CHARGING: The battery is currently charging
  • CONNECTED_NOT_CHARGING: The battery is connected to a power source but not charging
  • DISCHARGING: The battery is discharging
  • FULL: The battery is fully charged
  • UNKNOWN: The battery state is unknown

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Complete Example

import flet as ft

async def main(page: ft.Page):
    page.title = "Battery Monitor"
    
    battery_level = ft.Text(size=30)
    battery_state = ft.Text(size=20)
    battery_save_mode = ft.Text()
    
    battery = ft.Battery()
    page.overlay.append(battery)
    
    async def update_battery_info():
        # Get battery level
        level = await battery.get_battery_level()
        if level is not None:
            battery_level.value = f"Battery: {level}%"
            
            # Change color based on level
            if level < 20:
                battery_level.color = ft.colors.RED
            elif level < 50:
                battery_level.color = ft.colors.ORANGE
            else:
                battery_level.color = ft.colors.GREEN
        else:
            battery_level.value = "Battery level unavailable"
        
        # Get battery state
        state = await battery.get_battery_state()
        battery_state.value = f"State: {state.value}"
        
        # Check battery save mode
        save_mode = await battery.is_in_battery_save_mode()
        battery_save_mode.value = f"Battery save mode: {'ON' if save_mode else 'OFF'}"
        
        await page.update_async()
    
    def on_state_change(e: ft.BatteryStateChangeEvent):
        battery_state.value = f"State: {e.state.value}"
        page.update()
    
    battery.on_state_change = on_state_change
    
    async def refresh_clicked(e):
        await update_battery_info()
    
    page.add(
        battery_level,
        battery_state,
        battery_save_mode,
        ft.ElevatedButton("Refresh", on_click=refresh_clicked),
    )
    
    # Initial update
    await update_battery_info()

ft.app(main)

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Platform Availability

The Battery service is available on all mobile and desktop platforms:
PlatformSupport
Android✓
iOS✓
macOS✓
Windows✓
Linux✓
Web✓
Note: Battery information availability may vary depending on the device and platform capabilities.

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