I had a bit of a play with a run time clock module yesterday. It's an I2C device that I got as a cheap import from Hong Kong using the DS1307 chip.
Basically once you've got the right libary it's really simple to use, you don't even need to set the address, just set the date and time in code and read it back when you need it.
One of the key things to watch out for is some of these boards have a simple battery charge circuit so you'll need to use a LIR2032 not a CR2032.
Here's a bit more detail Workshopshed: Real Time Clock - DS1307
and the code I used https://github.com/Workshopshed/RTC_DS1307