See if you can guess what the new Batteries Widget for Mac app does. That’s right. It adds an iOS-style battery widget to the Mac’s Today panel, in the Notification Center. Anytime your iPhone/iPad/iPod Touch is on the same Wi-Fi network as your Mac, its battery level will show up in the widget.
You will get low-battery notifications when your devices start to run out of juice. Plus, the app shows battery levels for trackpads, AirPods and so on.