Calculators › Energy storage AC energy above a reserve calculator
AC energy above a reserve
For a fixed rated DC capacity, subtract the reserve state from the starting state before applying discharge conversion efficiency; no charging occurs during delivery.
E ac = E nom × ( S O C start − S O C min ) × η d 100 × 100 E_{\text{ac}} = \frac{E_{\text{nom}} \times \left(\mathrm{SOC}_{\text{start}} - \mathrm{SOC}_{\text{min}}\right) \times \eta_{d}}{100 \times 100} E ac = 100 × 100 E nom × ( SOC start − SOC min ) × η d
Calculator
Enter the values you know and leave one box empty. Calculate finds the empty one, the result or any input.
Worked example
Given
E nom E_{\text{nom}} E nom 400 kWh S O C start \mathrm{SOC}_{\text{start}} SOC start 80 % S O C min \mathrm{SOC}_{\text{min}} SOC min 25 % η d \eta_{d} η d 92 % E ac = 400 × ( 80 − 25 ) × 92 100 × 100 = 202.4 E_{\text{ac}} = \frac{400 \times \left(80 - 25\right) \times 92}{100 \times 100} = 202.4 E ac = 100 × 100 400 × ( 80 − 25 ) × 92 = 202.4
Symbols and units
Symbol Meaning Unit
E ac E_{\text{ac}} E ac AC energy deliverable kWh E nom E_{\text{nom}} E nom rated DC energy kWh S O C start \mathrm{SOC}_{\text{start}} SOC start starting state of charge % S O C min \mathrm{SOC}_{\text{min}} SOC min minimum reserve state % η d \eta_{d} η d discharge conversion efficiency %
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