Use this rooftop solar storage duration calculator to turn operational assumptions into a clear planning estimate. Enter values that match your own workload or site, then review the main result, supporting metrics, and interpretation. The calculation runs locally in your browser and exposes every major variable, making it useful for scenario comparison, budgeting, and early-stage design. Results remain estimates and should be checked against measured performance and project-specific constraints.
The result estimates how long the battery can support a constant average load after depth-of-discharge, reserve, and discharge-efficiency adjustments.
Planning estimate only. Confirm important decisions with measured data, provider documentation, equipment specifications, and qualified professionals where appropriate.
A 20 kWh battery at 90% depth of discharge, 92% discharge efficiency, and 10% reserve delivers 14.904 kWh. At a 2.5 kW load, duration is 5.96 hours.
They represent separate planning limits: a battery-use limit and an additional operational reserve.
Yes, but this calculator models battery discharge without simultaneous charging.
You can, but the result then represents a conservative constant-peak scenario.
No. Confirm that the inverter can supply the instantaneous load separately.
Load variation, temperature, aging, standby use, and control limits can reduce delivered energy.
| Item | Meaning |
|---|---|
| Adjustment | Applied as |
| Depth of discharge | usable share of nominal capacity |
| Reserve | share held back after depth limit |
| Discharge efficiency | share delivered after conversion losses |
| Average load | delivered kWh ÷ kW |