03-04-2019 06:35 AM
Start > Settings (gear icon) > System > Power and Sleep > Additional Power Settings > Change Plan Settings > Change Advanced Power Settings > Expand "Battery" near the bottom of the list. You'll see settings for Low Power Notification and Critical Power Notification. Turn those on. If they're already on, cycle them to off, reboot, then set them back to on and reboot, again.
Also check the "Low battery level" setting in that same box to make sure the percentage is 10% or wherever you'd like it to be.
You can also change Critical Battery Action to hibernate, which will at least write the current state to disk before shutting down, allowing you to restart where you left off once you reconnect the computer to power.
There are cases where none of that will work, requiring a dive into the registry to find and fix what's messed up. Easier to just reset the machine to out-of-the-box condition using OKR or enable Lenovo's battery gauge.
Some other ideas are in this article.