With only time keeping, Watchy should have a battery life of 5-7 days, while with fetching data over WiFi, it should last between 2-3 days. These numbers can be extended through further optimizations (e.g. sleep during off hours, waking up only on motion/tilt, etc.).
By default it wakes up the CPU and updates the display every 60 seconds, but you could totally change this to make it only update on demand (the most efficient would be by button press) which should extend the battery life waaay beyond 7 days.
That looks like a great project the battery life must be iconic
They have a page about that: https://watchy.sqfmi.com/docs/battery-life
By default it wakes up the CPU and updates the display every 60 seconds, but you could totally change this to make it only update on demand (the most efficient would be by button press) which should extend the battery life waaay beyond 7 days.
I have one and it easily lasts a week or so.