Ok so I've had a weird issue with any (two different) DS1307 boards and plugging into Raspberry PI via different methods, one is direct wiring to the I2C-1 port, and the other is via a Grove interface piggybacked of Re-speaker Pi board. Both see the RTC board when the battery was disconnected, but insert the battery, and the RTC goes dead.
Went into snooping on the I2C line to see the Pi addressing all addresses and no response when the battery was connected...
The ISSUE! as I've found and want to ensure others don't endure the pain, is the Battery (if it's a new one) is the same or more voltage than 3.3V which according to the data sheet will send the RTC to sleep!.
These boards ideally need 5V, not 3.3V to be powered reliably.