Weather station based on esp8266 and BME280 sensor. Upload to thingspeak.com every 1 minutes. Read data from sensor every 3 seconds and post them on serial and oled screen. Every 3 minutes i get data from openweathermaps.org.
10 Wp solar panel, two 3400 mAh Li-CoO2 18650 batteries in parallel, permanent small ~50 mW load. A shunt regulator limits battery voltage to 4.1 V. An externally powered ESP32 measures sol and bat powers for ThingSpeak.