1---
2category: Sensors
3---
4 
5# useBattery
6 
7Reactive [Battery Status API](https://developer.mozilla.org/en-US/docs/Web/API/Battery_Status_API), more often referred to as the Battery API, provides information about the system's battery charge level and lets you be notified by events that are sent when the battery level or charging status change. This can be used to adjust your app's resource usage to reduce battery drain when the battery is low, or to save changes before the battery runs out in order to prevent data loss.
8 
9## Usage
10 
11```ts
12import { useBattery } from '@vueuse/core'
13 
14const { isSupported, charging, chargingTime, dischargingTime, level } = useBattery()
15```
16 
17| State           | Type      | Description                                                       |
18| --------------- | --------- | ----------------------------------------------------------------- |
19| isSupported     | `Boolean` | If the Battery Status API is supported in the current browser.    |
20| charging        | `Boolean` | If the device is currently charging.                              |
21| chargingTime    | `Number`  | The number of seconds until the device becomes fully charged.     |
22| dischargingTime | `Number`  | The number of seconds before the device becomes fully discharged. |
23| level           | `Number`  | A number between 0 and 1 representing the current charge level.   |
24 
25::: warning Browser Support
26The Battery Status API has limited browser support. It is currently only available in Chromium-based browsers. Always check `isSupported` before using the values.
27:::
28 
29## Use-cases
30 
31Our applications normally are not empathetic to battery level, we can make a few adjustments to our applications that will be more friendly to low battery users.
32 
33- Trigger a special "dark-mode" battery saver theme settings.
34- Stop auto playing videos in news feeds.
35- Disable some background workers that are not critical.
36- Limit network calls and reduce CPU/Memory consumption.
37 
38## Component Usage
39 
40```vue
41<template>
42  <UseBattery v-slot="{ isSupported, charging, level }">
43    <div v-if="isSupported">
44      <p>Is Charging: {{ charging }}</p>
45      <p>Battery Level: {{ (level * 100).toFixed(0) }}%</p>
46    </div>
47    <div v-else>
48      Battery API not supported
49    </div>
50  </UseBattery>
51</template>
52```
53 
54## Type Declarations
55 
56```ts
57export interface UseBatteryOptions extends ConfigurableNavigator {}
58export interface UseBatteryReturn extends Supportable {
59  charging: ShallowRef<boolean>
60  chargingTime: ShallowRef<number>
61  dischargingTime: ShallowRef<number>
62  level: ShallowRef<number>
63}
64export interface BatteryManager extends EventTarget {
65  charging: boolean
66  chargingTime: number
67  dischargingTime: number
68  level: number
69}
70/**
71 * Reactive Battery Status API.
72 *
73 * @see https://vueuse.org/useBattery
74 *
75 * @__NO_SIDE_EFFECTS__
76 */
77export declare function useBattery(
78  options?: UseBatteryOptions,
79): UseBatteryReturn
80```
81