Powersupply (GTK3 tool)
A Gtk3 based application displaying the current battery status, charging power, and other related information:
apk add powersupply
A shell tool which gathers power consumption along with other statistics such as system load, number of context switches etc.
Only works while running on battery power.
Can also monitor GPU power consumption, but that is not of much use for phones, since it only supports Intel GPUs (at the time of this writing).
Install: No package yet. Download tarball from here or:
git clone git://kernel.ubuntu.com/cking/powerstat.git cd powerstat make make install
for more options.