Work out solar powered sensor sizing instantly with clear inputs, formula shown and shareable results.
Solar sensor nodes must be sized on the worst month, not the annual average, because a December deficit cannot be repaid from a June surplus. Panel size is daily energy divided by worst-month sun hours and system efficiency, and the battery must ride out the longest expected cloudy spell.
Solar node sizing
panel W = daily Wh / worst-month peak sun hours / efficiency; battery Wh = daily x autonomy days / usable fraction
Because the battery only buffers days, not months. A node sized on the annual average dies every winter.
5-10 days for temperate latitudes, more where extended overcast is common. Each extra day is cheap in battery terms compared with a bigger panel.