RGBZONE 150 Amps Power Analyzer, High Precision RC Watt Meter with Digital LCD Screen for RC, Battery, Solar, Wind Power

Will it shut off the device when battery drops to a particular voltage?

(revised) I want to measure total watt-hrs for one week day and night from a solar panel. With an auxiliary battery can I do this?

What is the third pin on the side used for? The other two are labeled positive and negative

Do you write it into the circuit between the solar panel controller and the battery or can you splice into the wires and get accurate reading?