As explained in my last post, I moved my indoor greenhouse to the exterior but wanted to keep monitoring temperature and humidity, without relying on wall outlets.
I started with a 10AH power bank attached to the esp8266 circuit and it lasted a few days before I had to recharge it. Not great.
A small 5v solar cell panel was laying around in the collection of unused electronics and it looked like a great project to make use of it. After hooking it up to a li-ion battery and its charging circuit I started optimizing the code for better power consumptions. Another addition was a battery voltage reader using esp8266's ADC and a voltage divider circuit with reasonably low power draw. These readings are also pushed to influxdb.
The sensor probe has been running for more than two weeks now, without a single manual charge, and by looking at the metrics below, it is clear that at current deep sleep interval (90 seconds) there is a break even situation in terms of day charging vs night power consumption, even with two consecutive cloudy days, which is exactly what I am looking for :)
The source code is available at github