Clear assumptions. No black box.

EV running cost

Battery energy = annual distance ÷ 100 × EV efficiency. Grid energy = battery energy ÷ (1 − charging loss). Annual charging cost = grid energy × your weighted home/public electricity rate.

EV vs petrol / hybrid

Total cost = purchase price − resale value + operating costs over the selected period + total finance cost. The comparison excludes tax, inflation, incentives and opportunity cost. The displayed break-even is a simple upfront estimate, not a discounted-cash-flow forecast.

Charging cost

Battery energy for a session = usable battery capacity × state-of-charge change. Grid energy accounts for the entered charging loss. Charging time is estimated from grid energy and charger power; it does not model fast-charging taper, battery temperature or site conditions.

Solar + EV Charging Match

Aggregate solar surplus = gross solar generation − gross non-EV household use for the identical active charging interval, never below zero. Estimated session wall energy = average wall-side charging power × active charging duration. The indicative aggregate solar match is the lower of those two amounts. The remaining session wall energy is multiplied by your entered cents-per-kWh usage rate and divided by 100 to show an indicative variable usage charge in Australian dollars.

Battery-side energy gap = usable battery capacity × state-of-charge change. It is shown separately because charging efficiency is not an input. The result does not predict whether the target SOC will be reached.

The comparison uses interval totals and does not trace electricity flows within the window. Actual solar matching can be higher or lower. Charging power may vary, and the model excludes charging losses, tapering, vehicle limits, temperature, auxiliary loads, SOC estimation differences, forecasts, weather, home batteries, curtailment, exports, network and inverter limits.

The usage-charge estimate is not a bill estimate or savings claim. It excludes supply and demand charges, rate changes, discounts, fees, taxes, concessions, feed-in credits and foregone export value. The tool does not recommend a tariff, vehicle, charger, solar system, battery or installer; assess installation or equipment suitability; guarantee savings; or determine V2H/V2G compatibility.

How we protect the result

The calculators reject missing or invalid inputs and show an estimate notice with the main reasons actual outcomes may differ. We version formula changes and test calculation identities before release.