Add a Epoch convert function, so you can easily update the RTC if the time is smaller in RTC then in Compiler Time&Date?

[MarcelVollebregt]

Maybe add:
/*!

• \brief Convert to Unix UTC epoch time_t
• \return

•  Unix epoch time_t seconds since 1970.
  

*/
time_t ErriezDS1307::getEpoch(struct tm *rdt)
{
time_t t;

// Convert date/time struct tm to time_t
t = mktime(rdt);

// An offset is needed for AVR target

#ifdef ARDUINO_ARCH_AVR
t += UNIX_OFFSET;
#endif

// Return Unix epoch UTC
return t;

}

It helped me to get an automatic RTC update based on Compiled time&date in my application:
if (rtc.read(&rtc_dt))
{
Serial.println("Time fetched from RTC IC....");
}
else
{
Serial.println("Time NOT fetched from RTC IC....");
}

if (rtc.getEpoch(&dt) > rtc.getEpoch(&rtc_dt))
{
// Set new date time
Serial.print(F("Set RTC date time..."));
if (!rtc.write(&dt)) {
Serial.println(F("FAILED"));
} else {
Serial.println(F("OK"));
}
}
And of course no battery yet installed.