Calculator methodology
The assumptions are part of the answer.
The calculator separates stored energy, load energy, continuous output, startup output, reserve, and portable-solar input. It is a planning model—not a product test or performance guarantee.
Usable starting energy
Rated Wh × starting-charge percentage × remaining energy after the selected reserve × 85%. The final factor is a disclosed 15% conversion-and-variation allowance for planning, not a measured efficiency claim about any product.
Daily load energy
Each selected load contributes running watts × hours per day. The daily budget is the sum of those entries. Presets are editable planning examples based on typical product categories, not a centralized empirical appliance database.
Battery-only support
Usable starting energy ÷ daily load energy produces days of support before recharge. The displayed hours are the same result converted to hours and do not model minute-by-minute appliance cycling.
Portable solar
The lower of panel nameplate watts or the station's solar-input limit × peak-sun hours × field-yield percentage. The 70% default is editable and accounts broadly for angle, heat, cloud, cable, controller, and charging losses.
Output checks
The continuous check sums all selected running watts. The conservative startup check adds the largest single startup increment to that sum. Real sequencing and electronic controls may differ, so rehearse the exact load combination.
Target result
The load and, when enabled, planning-day solar are prorated across the selected duration. A margin or deficit is an energy result only; continuous and startup output must also clear independently.
Known limitations
The model does not validate connectors, voltage, current, polarity, battery temperature, degradation, charging timing, weather, fixed wiring, transfer equipment, HVAC design, medical adequacy, or installation. Verify current manuals and test the actual equipment and loads.