Hi,

I am planning to use the M5Core Ink as a temperature sensor, but the device runs out of battery after about 12hrs or so even using m5.shutdown . (my goals would be 6 months+ of lifespan)

To get a standard example, I used the M5core Ink NTP project (https://github.com/hpsaturn/m5coreink-ntp-clock) that seems well known to compare with others.

I am charging the battery for 6 hours before running on battery.
With the default 1 minute shutdown and using RTC to wake the device up, the battery still does not last more than 12 hours. The device is only staying up a couple seconds to getRTC, and should go back in deepsleep through shutdown. I tried longer shutdown (5min), but that did not increase the battery life even though I could see that clock was refreshed only every 5 minutes.

Using https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-battery-life for battery duration, the battery being 390mAh and device using 0.0025mA (according to https://www.gwendesign.ch/kb/m5stack/m5coreink/) in shutdown, I should expect months at least.

Has anyone data to compare or recommendations?

Thank you