Disclosed herein are various battery power measurement devices, methods, and related apparatuses. In one embodiment, a method of measuring a battery power can include: (i) detecting a voltage and a temperature at an output terminal of a battery; (ii) obtaining a first correction coefficient based on a battery open-circuit voltage at a previous sample time; (iii) obtaining a second correction coefficient based on the battery temperature; (iv) calculating a real-time battery open-circuit voltage by using the voltage at the output terminal of the battery, the first and second correction coefficients, the battery open-circuit voltage at the previous sample time, and a time interval between the previous sample time and a present sample time; and (v) converting the real-time battery open-circuit voltage into a battery power measurement for display.