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.
Problem definition. Increased awareness of the economic and social effects of aging, deterioration and extreme events on civil infrastructure has been accompanied by recognition of the need for advanced structural health monitoring and damage detection