From watts to watt-hours.
Required nominal Wh = average load in watts × hours ÷ (usable fraction × starting-charge fraction).
Average load = running watts × time-in-use fraction + station idle draw. Usage reduces average energy demand; it does not reduce the running-output rating a station needs.
A worked example.
A constant 100 W load plus 10 W of station idle draw for eight hours uses 880 Wh. At 80% usable capacity and full starting charge, the modeled nominal battery requirement is 880 ÷ 0.8 = 1,100 Wh.
At 50% starting charge, the same calculation needs 2,200 Wh of nominal capacity. A larger battery and a fuller battery are different ways to change available energy.
What this number leaves open.
A battery can have enough energy and still lack the output to start a motor. These quick tools do not know your devices’ startup demand. The transferred plan uses running watts as a placeholder for starting watts; replace it or add individual appliances before relying on a match.
Battery condition, temperature, inverter behavior and real appliance use can change runtime. No solar charging, extra batteries or replenishment is included. For a fridge or mixed appliance load, start with the fridge guide or the full planner.