I haven't developed on the Kindle ecosystem, but with old Nook devices I am able to set a screensaver, alarm, and put the device into deep sleep between refreshes. This changed my battery life from ~48 hours into 30+ days of battery life even with some old devices.

The "electric sign" app does this, which is where I referenced the code.

With trmnl, the image only refreshes every 10 mins so the device will set a ~9 minute alarm to wake the device right before it needs to load the next update.

The refresh period is also configurable so a slower refresh interval (e.g. every hour for less time-sensitive screens) yields larger battery savings