Quote Originally Posted by jellis00 View Post
I have an application wired per my crude schematic above with Schottky BAT42 diodes on each leg which has been running on 5v for many weeks and the lithium CR2032 backup battery is still showing 3.11vdc. So I don't see the need of the resistor in series with the schottky diode or two shottky diodes...doing this just drops the supply voltage to the DS1337 some more by the addition of the voltage drop across the resistor or the additional diode.
The two diode or diode/resistor was a UL requirement on my design. Lithium coin cells cannot be back charged above a certain current level.