The Solar Carport Storage Duration Estimator calculates how long a battery can support a steady electrical load after accounting for usable depth of discharge and discharge efficiency. It separates nameplate battery energy from the energy that can actually reach the load.
This quick estimate is useful for carport microgrid concepts, EV-charging support, peak shaving, and backup planning. Real load profiles fluctuate, so the duration should be treated as a constant-load benchmark rather than a guarantee of runtime.
Use nameplate kilowatt-hours, not power capacity in kilowatts.
Apply the operating depth-of-discharge limit for the battery.
Enter discharge-path efficiency from stored DC energy to the supported load.
Use the average kilowatt demand expected during the discharge interval.
The result is hours at that constant load; changing demand changes the actual duration.
Usable energy = Battery capacity × Depth of discharge
Delivered energy = Usable energy × Discharge efficiency
Storage duration (h) = Delivered energy (kWh) ÷ Supported load (kW)
Load remains constant, the battery begins at its defined full state, and auxiliary consumption, temperature derating, power limits, and aging are not modeled separately.
Duration is the amount of time the modeled delivered energy can serve the entered average load. It does not indicate whether the battery inverter can meet short power peaks.
Check both battery energy and power ratings. Backup designs should also model time-varying loads, reserve state of charge, temperature, and battery aging.
Usable energy = 1,000 × 0.90 = 900 kWh
Delivered energy = 900 × 0.92 = 828 kWh
Duration = 828 ÷ 250 = 3.312 hours
Estimated duration: 3.31 hours
At a constant 250 kW load, the modeled battery can deliver energy for roughly 3 hours and 19 minutes.
Duration is the amount of time the modeled delivered energy can serve the entered average load. It does not indicate whether the battery inverter can meet short power peaks.
Use a site- and system-specific value for the resource, efficiency, production, price, or load input that drives this calculation. Keep its time period and unit consistent with the other entries.
Check both battery energy and power ratings. Backup designs should also model time-varying loads, reserve state of charge, temperature, and battery aging.
A required denominator or physical quantity must be greater than zero, while percentage inputs must stay within their displayed limits. Reset restores the worked-example values.
Confirm site data, equipment specifications, system boundaries, applicable codes, and the time basis of every input. Use a detailed model and qualified professional review for final engineering or investment approval.