Since kernel 4.14 (I believe), the T630 battery charge is reported as 0% per /sys/class/power_supply/hid-[mac]-battery/capacity (also in e.g. GNOME's Power settings pane). Prior to that (4.13.x and below), battery charge was correctly reported. I've tested it on two different devices with different Bluetooth chipsets with the same result. I've also tested with two other battery-powered Bluetooth peripherals that report their charge level (presumably via a standard Bluetooth profile?) - a Logitech K810 keyboard (two of) and a non-Logitech device. The non-Logitech device has consistently reported correct charge levels across kernel versions (at least up to 4.15.x). The K810 keyboard battery reporting seems to vary from kernel to kernel since 4.14 - e.g. 4.15.3 it showed 0, 4.15.6 it showed the correct charge, 4.15.9/4.15.10 it shows 0 again. Downstream bug: https://bugzilla.redhat.com/show_bug.cgi?id=1541460