I've only got basic skills but i am trying to hack together an ESP32 + temperature sensor to send periodic readings out via Wi-Fi. I've managed to get the board to connect to Wi-Fi, read the sensor, send the data, shut down for deep sleep until its ready to repeat the process - but I'm unsure of how to handle powering the device.
By my extremely rough calculations it appears that it takes very roughly 15 seconds for each cycle to complete, and uses about 160ma while its doing so. I thus conclude that if I get a 1 watt solar charger with built in battery (the type used for powering cellphones - like this one) it should provide enough power.
My problem is this - what typically happens to these solar chargers when the battery is full and they continue to be exposed to power ? (In summer we get 2-3 times as much sun as in winter, but very variable weather, and the most important l time to read the temperatures is early in the morning when its dark in winter, so I don't want the battery to run flat).
Are there other, simple, cheap ways of powering my board from solar, preferably which don't require to much work at the component level ? If there are, are there any simple, cheap ways of measuring the remaining battery capacity and reporting this to esp32 board ? (If I know the battery status I may be able to schedule readings more or less frequently to ensure the board does not discharge ?)
Relatedly, I've found this item on Aliexpress (ie a solar charger sans battery - where you are meant to add your own battery). I'm hoping that I can combine it with a 3000mah or so flat battery and embed my ESP32 inside it for a very easy to build setup - is this a sensible solution?