How to prevent possible overcharging of the third battery in ThinkPad is as follows:
Download and install the Embedded Controller Program to update the thinkpad machine.
Note:
1. In order to determine the BIOS on the ThinkPad A31 or A31p system Type, press the F1 key during the startup process, the BIOS main interface will display the BIOS version, the first few digits of the BIOS version number are 1GET or 1NET.
2. When updating the Embedded Controller Program on the ThinkPad system, if you find the following error message, please make sure that the AC adapter is correctly connected to the thinkpad machine and provides stable power to the machine. Error: "This process requires power to avoid an accidental power-off during an update. Connect the AC adapter to the computer."
3. If you still get an error message or the ThinkPad system after checking the AC adapter If you have any of the faults listed in the additional information, you should contact the service center to have your ThinkPad machine repaired.
Additional information:
The following errors displayed in the power detection circuit mean that the ThinkPad system does not correctly detect the AC adapter. These errors may occur when using real IBM or real Lenovo batteries or third-party batteries.
1. The battery icon on the taskbar displays incorrect power or battery information. For example: using AC adapter, the battery icon still shows working in battery mode.
2. The power icon on the taskbar continuously changes between external power supply and battery.
3. Because the AC adapter cannot be detected to be working properly, the BIOS or Embedded Controller Progra cannot be updated.m.
4. For the ThinkPad A30 system, the Embedded Controller Program is updated to version 1.08 or higher. For the ThinkPad A31 system, after the Embedded Controller Program is updated to version 1.05 or higher, the machine cannot work in battery mode. And the battery cannot be charged.