Lenovo has included a battery 'Conservation Mode', which prolongs your battery longevity (how long the battery will tend to last before finally needing to be replaced ) by limiting charging to battery to 55% ~ 60% of the battery capacity rather than fully charging it to 100%. The trade off is that the system will not run as many hours as would otherwise be possible with a 100% charge.
You can enable the 'Conservation Mode' by following these steps:
Step 1. Double Click on the Lenovo Energy Manager icon in the Taskbar.
Step 2: Click on the expand button on the Energy Manager Windows
Step 3: Click on 'Settings' tab on the windows.
Step 4: Select/Enable battery 'Conservation Mode' in the Lenovo Energy Manager
P.S. You don't have to use this mode all the time, but if you are using the laptop with the AC adapter constantly connected, and don't really need the extended battery time, then this mode is something you should consider enabling to reduce unnecessary battery wear.