Discharge energy is the kWh you actually pull from the bank each cycle—not the full nameplate. This guide walks through the DoD and battery discharge energy calculator: nominal capacity, DoD %, and the discharge yield available to inverters and loads.
Benefits
- Discharge energy (usable) = nominal kWh × (DoD ÷ 100).
- Shows reserved kWh held above your discharge floor.
- Compare discharge yield across 50%, 80%, and 90% DoD policies.
How it works
- Enter nominal bank kWh from module sticker or datasheet.
- Set planned depth of discharge % for the cycle you are modeling.
- Read discharge energy in kWh and Wh—the yield per discharge event.
FAQ
What is battery discharge energy at a given DoD?
Discharge energy ≈ nominal kWh × (DoD ÷ 100). Example: 20 kWh nominal at 80% DoD → 16 kWh discharged per cycle; 4 kWh remains as reserve above the floor. That 16 kWh is what loads can consume before hitting the BMS low-voltage cutoff.
How is discharge energy different from energy yield?
In planning terms they are the same usable energy released between charge top and discharge floor—yield per cycle. Marketing yield sometimes includes round-trip efficiency; this calculator gives gross discharge kWh from capacity and DoD before inverter and cable losses.
Does a deeper DoD always mean more discharge energy?
Yes, mathematically—higher DoD % multiplies more of nominal kWh into discharge energy. But deeper daily DoD reduces cycle life for most chemistries. Compare discharge kWh at 80% vs. 90% DoD, then weigh autonomy against replacement interval.
Technical specifications
- Discharge kWh = nominal_kWh × (DoD% ÷ 100).
- Reserve kWh = nominal − discharge_kWh.
- Discharge Wh = discharge_kWh × 1,000.
- Related: battery-depth-of-discharge, battery-dod-to-usable-energy-calculator.
DoD defines how much of the tank you drain
A battery cycle discharges from a high state of charge to a lower floor set by chemistry, warranty, and BMS. Depth of discharge is the fraction of nominal energy in that swing. Modeling discharge energy as nominal × DoD % answers how many kilowatt-hours one cycle delivers—before asking how many cycles per day you stack.
Discharge yield scales linearly with DoD
Doubling DoD from 40% to 80% doubles discharge kWh from the same nominal bank. The trade is cycle life and thermal stress, not arithmetic. Run the calculator at your minimum and maximum acceptable DoD to bracket discharge energy; pick the operating point where autonomy and longevity meet project goals.
From discharge kWh to system design
Discharge yield feeds inverter runtime, solar self-consumption stacking, and generator overlap math. Subtract inverter and wiring loss after gross discharge kWh. For nightly off-grid use, multiply single-cycle discharge energy by nights of autonomy required—or use Critical Load Analysis when loads are not constant across the discharge window.