Yep, any help with the data interpretation would be great Ari Cooper Davis has expressed interest in helping with this also. I'm far more comfortable with the hardware side of things. And even then for this I'm merely modifying existing logger designs https://thecavepearlproject.org/how-to-build-an-arduino-data-logger/
with my primary motivation being to put together cheap and accurate enough loggers to get a better idea of how popular dales caves flood after it rains.
Quick update: I've now changed the design/code so I can turn the sensors and screen off when they're not needed to save power.
And done some experiments to see how efficient it is (see graph below), the bottom axis is about 20 seconds long*, I'm using a INA219 module to monitor current and voltage, the voltage holds steady at 3.3V while the current changes depending on what the device is doing. The device is in sleep mode by default, the plot shows 2 logging events, each event has 2 current peaks, the first is the sensor activating and taking a reading, the second is the SD card writing to file before going back to sleep I think.
In sleep mode it averages a power consumption of around 3 mA with 2 18650 cells so in theory should last around 2000 hours depending on the logging frequency.