Ray, as you pointed out in your previous post:
You are right that DS1307 requires at least 4.5V VCC. So the previous version of the OpenSprinkler that used DS1307 has its VCC tied to +5V, whereas PCF8563 can work with 3.3V so its VCC is tied to 3.3V.
So wiht DS chip I have to connect VCC of DS to 5V. But the supercap’s max voltage is 3.3V, so I’m interested how the complete schematic with DS chip should look like.