Battery capacity (kWh)
The total energy your battery can hold, measured in kilowatt-hours. This is the manufacturer’s nameplate figure — what the brochure or spec sheet calls “usable capacity”, not the gross cell capacity.
How the simulator uses it
Capacity is the ceiling on how much the battery can hold. Once the charge hits this value the battery is full — any further solar surplus exports to grid (grid-tied) or curtails (off-grid). Lower bound is set by the min-reserve field.
Typical values
- Tesla Powerwall 2: 13.5 kWh
- Tesla Powerwall 3: 13.5 kWh
- LG RESU 10H: 9.3 kWh usable
- BYD HVM 11.0: 11 kWh usable
- Off-grid caravan setups: typically 2–5 kWh per LFP wall pack, often paralleled for 10–20 kWh total.
Common pitfalls
- Use the usable capacity, not gross cell capacity. Manufacturers often quote both — a battery with 16 kWh of cells but a 10% reserve at each end ships with ~13 kWh usable. Enter 13.
- Set to 0 if you have no battery — the simulator will skip all battery logic and run as a grid-only or solar-only system.
Closes this tab and returns to the calculator.