Started having problems with DS1307. Thought it was the battery, but after two replacements realized that either the program was re-writing registers or the chip was bad.
Replaced the chip two weeks ago. Reprogrammed the 16X2 LCD display to show times from the DS1307 [lower] and PCF 85263 DemoBoard [upper].
![](http://batteryrandd.wongwelch.org/wp-content/uploads/2019/04/DemoBoard_IMG_20190409_103755-Copy.jpg)
Picture was 4/21/2019 with a difference of 31 seconds. Checked today, now 30 seconds. Initial difference was about 36 seconds.