Observed arrival · 2026-09-17
WinterWatt: Solar for the Darkest Month
An off-grid solar sizing calculator built around the darkest month, terrain shading, battery storage, generator use, and cable costs.
Field notes
WinterWatt models a winter-critical off-grid system through site latitude, array orientation, design month, terrain skyline angles, cloud adjustment, load, storage, generator economics, and cable parameters. Its outputs include the array needed for full solar coverage, solar lost to a ridge, battery capacity, generator fuel cost, and conductor sizing. The page directs users to PVGIS for measured monthly irradiance and explicitly limits cable analysis to voltage drop rather than full electrical-code compliance.
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Editorial observations of this landing page, not a rating.
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