Separate electric driving from fuel driving.
For an EV, all distance is modelled as electric. For a PHEV, your electric-distance share determines the split: electric kilometres use the electricity consumption input, and the remaining kilometres use the fuel-mode consumption input. Your charging frequency, route and driving conditions can change both.
Allow for charging losses and tariffs.
Electricity purchased is battery energy divided by one minus the loss percentage. For example, 18 kWh delivered to the battery with 10% losses requires 20 kWh from the supply. If your consumption figure already measures electricity at the charger, enter zero additional losses to avoid counting them twice.
Enter an effective tariff reflecting the charging you expect to use, including public charging where relevant. If you use solar, consider its opportunity cost and any additional equipment cost rather than automatically treating it as free.
Understand the payback.
Simple payback divides extra vehicle and charger cost by annual energy and maintenance savings. When savings are zero or negative, the model shows no payback. Maintenance savings can be negative if the alternative costs more to maintain. Net savings deduct upfront costs over your selected comparison period.
The comparison excludes financing interest, insurance differences, resale values, depreciation, tax, inflation and future price changes. It is not a full ownership-cost comparison or a recommendation to replace a vehicle. Compare equivalent vehicles and test several assumptions using the sliders.
Make the costs part of the plan.
Journalled can help with budgets, forecasts and practical financial modelling.
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