Convert amp-hours to watt-hours
Convert battery amp-hours to stored energy in watt-hours. Wh = Ah × V.
Amp-hours (Ah) is the rating printed on most batteries, but it only tells the real story once you know the voltage — a 100Ah battery holds four times the energy at 48V that it does at 12V. Converting to watt-hours (or kWh) gives a voltage-independent figure you can compare directly against your daily load or against batteries rated at a different system voltage.
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Looking for a definition or a quick answer? See the solar & battery glossary for terms used on this page, or the FAQ for common sizing questions.
Sources & standards
- IEEE 1013 — Recommended Practice for Sizing Lead-Acid Batteries for Stand-Alone Photovoltaic Systems — Widely used engineering practice for days-of-autonomy and depth-of-discharge sizing methods, referenced here for the general sizing approach.
Estimates for planning only. Verify with a meter and follow NEC / local code; have a licensed installer confirm any system before purchase or wiring. See the methodology for formulas and sources.