Recommended · for some experience
Make your own Power Meter/Logger
Why people recommend it
A GreatScott! build recommended as a starting point for logging voltage, current and power with an INA219, and adapted by others for their own meters.
Watch for: The sensor has limited voltage and current range
In their words
Basically, I'm looking for something like this DIY power meter/logger (pictured below) but for higher currents (up to ~20A to be safe).
Steve Marwin on electronics.stackexchange.com, Jun 2019. CC BY-SA.