high sierra remaing battery time

This is a user-to-user support community, of which Apple product teams neither read, nor participate. No one here has an inside scoop from Apple Engineering about their product functionality decisions.

There are several inexpensive third-party applications in the Mac App Store that show battery time remaining in the menu bar. Search on battery time. Check the supported version of operating system, and reviews — before you purchase/download.

Run Mac on battery.

Applications > Utility > Activity Monitor

Click the "Energy" tab.

Stats will be appear at the bottom middle.

For more info: https://support.apple.com/en-us/HT201464

See this article Monitor your portable computer’s battery - Apple Support

That feature was removed in Sierra but has been restored in High Sierra.

Are you not seeing the option to Show Percentage?

Why would they remove this simple feature that existed before?

Only Apple could answer that question, and they won't answer.