I am currently working with a DS1307 RTC ('877A and I2C). All is well reading, writing, and displaying result to a typical LCD. The difficulty comes when using a battery (2032 Lithium coin) to backup the clock. Insert the battery, the display flashes: 04:04:04; remove it, time returns to accurate display and advance. Re-insert battery, display reads: 04:04:04... Its quite a fun game, but not very efficient way to keep the time. I've checked the voltage of the battery, wiring, and everything else I can think of - as well as tried some basic filtering. I've searched Google for any known issues and found nothing... Anyone can advise?