MINIMAL specs for Pi Zero W + Inky pHat

If I don’t have any peripherals but just the inky pHat 212x104 on the Pi Zero W, what is the minimal specifications for the battery (LiPo or otherwise) that is needed? (Voltage, Amperage/Wattage)

WiFi communications is only spurious, about once in 10 minutes for Weather update. NO fast moving graphics/text involved.

I can’t help you with the Inky but I can link you too some info on what current the Zero w draws.
FAQs - Raspberry Pi Documentation