Daily power consumption calculator

Each appliance contributes power times quantity, hours per day and duty cycle, summed separately for DC and AC loads. The demand at the battery is E_DC/η_cable + E_AC/(η_cable · η_inverter), since AC loads also pass through the inverter. If you enter a metered reading from a plug-in energy monitor, the calculator derives the real duty cycle and upgrades that row from assumed to measured.

No. Summing every surge is absurdly high because a compressor and a pump never start at exactly the same moment, while ignoring surges entirely is dangerously low. The correct figure is the single largest surge event plus the running base load of everything else — that is the sizing input for the inverter.

Only with limitations. It assumes repeating daily profiles and a constant power draw per appliance. Loads whose power depends strongly on load or temperature, such as an air conditioner in part-load operation, are not covered, and neither are reactive power or transients shorter than 100 ms.

Because compressor and pump never start at exactly the same moment. Summing all inrushes leads to absurdly large inverters; ignoring them to dangerously small ones that shut down at fridge start. Right is the largest single inrush event plus the running base load — exactly this number is the calculator’s peak load, and the three-way chart shows all three methods side by side.

A compressor fridge does not run 24 hours straight: it cycles, typically 35% of the time. 80 W × 24 h × 0.35 = 672 Wh instead of 1,920 Wh — the difference between usable and useless sizing. Catalogue values are marked as “assumption”; measurement mode (measured kWh over several days) back-calculates the real duty cycle and lifts the row to “measured”.

Because every AC watt-hour additionally carries the inverter loss: E_battery = E_DC/η_cable + E_AC/(η_cable × η_inv). At 90% inverter efficiency, 1,000 Wh of AC consumption costs about 1,134 Wh at the battery; the same 1,000 Wh as DC only 1,020 Wh. If the AC share exceeds 70%, DC alternatives are worth a look (cooler, lights, router directly at 12/24 V).

Yes — since 5 August 2026. Before that the form permanently showed the example list, because it only understood single numbers, not lists. Now you pick appliances from a 42-entry catalogue, set quantity and operating hours, and see each row's daily energy immediately. Your list is held in the address bar, so the link is shareable and survives a reload.

From a versioned dataset aggregating manufacturer datasheets, the EU energy label database EPREL and measurement series from off-grid practice. The dataset states about itself that appliance power varies considerably between models — which is why power is editable in every row, and why a warning sits above the result for as long as duty cycles come from the catalogue.

Because some appliances can do both — a laptop, a router or a TV runs off a 12 V supply just as well as through the inverter. That choice costs energy: an AC load additionally carries the inverter loss. For appliances with only one path (kettle: AC, roof vent: DC) the row simply states the path instead of feigning a choice.

Daily demand is recalculated immediately and every derived figure follows — continuous load, peak load, AC share and the ranking. That is the point of this calculator: to show which appliance drives the demand. In the example the fridge accounts for 43 %; dropping it changes the sizing of the whole system.

Because fifteen identically worded warnings stacked on top of each other would push the result out of view. The message now states how many appliances are affected and names the largest among them — the row where your own measurement changes the most. All affected appliances remain flagged in the warning's data.