Using The Ac Power Adapter; Charging The Battery - Lenovo ThinkPad T540p User Manual

3. For Low battery alarm or Critically low battery alarm, set the percentage of the power level and set
the action.
Note: If your computer enters sleep or hibernation mode when the battery is low, but the alarm message
has not yet been displayed, the message will be displayed when the computer resumes. To resume normal
operation, when the message is displayed, click OK.

Using the ac power adapter

The power to run your computer can come either from the lithium-ion (Li-ion) battery pack of your computer,
or from ac power through the ac power adapter. While you use ac power, the battery charges automatically.
The ac power adapter that comes with your computer has two basic components:
• The transformer pack that converts ac power for use with the computer.
• The power cord that plugs into the ac outlet and into the transformer pack.
Attention: Using an improper power cord might cause severe damage to your computer.
Connecting the ac power adapter
To connect the ac power adapter, do the following.
Note: Ensure that you perform the actions in the following order:
1. Connect the power cord to the ac power adapter.
2. Connect the ac power adapter to the power connector of the computer.
3. Connect the power cord into an electrical outlet.
Tips on using the ac power adapter
• When the ac power adapter is not in use, disconnect it from the electrical outlet.
• Do not bind the power cord tightly around the ac power adapter transformer pack when it is connected to
the transformer.
• Before you charge the battery, make sure that its temperature is at least 10°C (50°F).
• You can charge the battery when the ac power adapter is connected to the computer and the battery is
installed. You need to charge the battery in any of the following conditions:
– A new battery is installed.
– The percentage of power remaining is low.
– The battery has not been used for a long time.

Charging the battery

When you find that the percentage of power remaining is low or when the power alarm alerts you that the
remaining power is low, you need to charge your battery or replace it with a charged battery.
If an ac outlet is convenient, plug the ac power adapter into it, and then connect the ac power adapter to
the computer. The battery will be fully charged in about three to six hours. This is affected by the battery
size and the physical environment. You can check the battery charging status at any time through the
battery status icon in the Windows notification area.
Note: To maximize the life of the battery, the computer does not start recharging the battery if the remaining
power is greater than 95%.
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User Guide