Off-Grid Battery Bank Sizing
Required nameplate capacity (Wh and Ah) from daily load, days of autonomy, depth-of-discharge, and round-trip efficiency, per IEEE 1013 / 1561.
Formula and source
usable_Wh = daily_Wh * days_autonomy; nameplate_Wh = usable_Wh / (DoD * round_trip_efficiency * temperature_derate); nameplate_Ah = nameplate_Wh / system_V.
IEEE 1013 (Sizing Lead-Acid Batteries for Stand-Alone PV Systems); IEEE 1561 (PV / Hybrid Power Systems).
Audience
This tile is built for electricians and the adjacent professions in the Electrical group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
Related tools
Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.