chargingTime property

The chargingTime read-only property of the BatteryManager interface indicates the amount of time, in seconds, that remain until the battery is fully charged, or 0 if the battery is already fully charged or the user agent is unable to report the battery status information. If the battery is currently discharging, its value is Infinity. When its value changes, the BatteryManager.chargingtimechange_event event is fired.

Note: Even if the time returned is precise to the second, browsers round them to a higher interval (typically to the closest 15 minutes) for privacy reasons.