Based on Dell internal analysis, February 2019. When used with Dell systems with ExpressCharge. Within Dell Power Manager software, selecting ExpressCharge can recharge system battery from 0% up to 80% within 60 minutes. After charging has reached 80% capacity, charging speed will return to normal speed. Recommended for use with the provided Dell power adapter; not recommended with a smaller capacity power adapter. Charging time may vary +/-10% due to system tolerance.