Charge the computer

Use ac power

When the battery power is low, charge your battery by connecting your computer to ac power.

The battery is fully charged in about four to eight hours. If the power adapter shipped with your computer supports the rapid charge function, the battery is 80% charged in about one hour when the computer is turned off. The actual charging time depends on the battery size, the physical environment, and whether you are using the computer.

Battery charging is also affected by the battery temperature. The recommended battery temperature range for charging the battery is between 10°C (50°F) and 35°C (95°F).

Note: To maximize the life of the battery, the computer does not recharge the battery if the remaining power is greater than 95%.

Use P-to-P 2.0 charging function

Both the USB-C connector (USB 3.1 Gen 1) and the Thunderbolt 3 connector (USB-C) on the computer feature the Lenovo-unique P-to-P 2.0 charging function. When no ac power is available, this feature enables one computer to supply power to another computer through a USB-C to USB-C cable. When ac power is available for only one computer, this feature enables both computers to get charged by ac power.

Before using the function, ensure that:

The selected connectors support the P-to-P 2.0 charging function and power delivery function.
Always On USB and Charge in Battery Mode are enabled in UEFI BIOS of both computers, so that the function works even when the computers are off or in hibernation mode. To enable Always On USB and Charge in Battery Mode:
1. Enter the UEFI BIOS menu. See Enter the UEFI BIOS menu.
2. Click Config > USB to enable Always On USB and Charge in Battery Mode.

To use the function:

When no ac power is available:

The remaining battery power of computer A should be at least 30% and be 3% higher than that of computer B. To check the battery status, see Check the battery status and temperature. Connect the computers to each other with a USB-C to USB-C cable. In this situation, computer A works as the power supply. Once the remaining battery power of computer A is lower than 30%, computer A stops supplying power to computer B.
When ac power is available:

Connect the computers to each other with a USB-C to USB-C cable. Connect one computer to ac power. In this situation, ac power works as the power supply and both computers get charged.

Note: The actual charging speed using the Lenovo-unique P-to-P 2.0 charging function varies depending on many factors, such as the remaining battery power of the computers, the wattage of the ac power adapter, and whether you are using the computers.