5 in 1 power

Good day,

I purchased the remote battery pack for the AcuRite 5 in 1 system. The battery compartment has two (2) banks for AA batteries. It says if I replace only one bank at a time the sensor will not lose any data.

Question: Is the battery pack/sensor 3V DC then? I am looking at replacing the battery pack with a DC power adapter.

Question: How long with the unit run with fresh AA batteries stored in a shed and run to the sensor?

Thank you