@jack4566, You might wake the Boron to store sensor data in EEPROM periodically, and only use the Cellular Modem to upload the results once or twice a day. This post suggest ~1.5 years on 3xAA batteries when using an external timer and the EN Pin.
Rough Estimate:
- Energy used during Shutdown: 7.5 mWh per Day
- Energy used during Publish: 1 mWh per Publish (can vary depending on your Cellular Environment)
- 3xAA (Energizer L91's) are rated between 4,500 - 5,500 mWh, depending on your duty cycle
1 publish per day: 5000 mWh / ( 1 mWh + 7.5 mWh ) = ~588 days
But I don't know how to generate accurate timestamps (if req'd) for the data log using this Store/Shutdown & Publish Later approach, without adding an external RTC.