Worked exampleExported from Calvance
3D Printing Material & Electricity
Use filament weight and print duration from your slicer to estimate material and electricity costs separately, then add the two expenses.
View template and methodEV Charging Session Cost
Estimate charging cost from battery capacity, start and target charge, efficiency, electricity price and a fixed session fee. Includes an editable example.
Worked exampleExported from Calvance
Exported by the iOS App After importing, edit the numbers in Calvance.
When to use it
Estimate one charging session without assuming a particular car model. Use usable battery capacity, start and target state of charge (SOC), and the tariff at the billing point. The USD prices and 90% efficiency are illustrative inputs, not current rates or measured vehicle performance.
Inputs
USD
| Inputs | Default |
|---|---|
| Capacity (kWh) | 60 |
| Target SOC (%) | 80 |
| Start SOC (%) | 20 |
| Efficiency (%) | 90 |
| Tariff (USD/kWh) | 0.2 |
| Session fee (USD) | 1 |
Calculation method
Multiply usable capacity by the target-minus-start charge fraction. Divide that battery energy by efficiency to estimate energy at the billing point, then multiply by the tariff and add the fixed fee. A 60 kWh battery going from 20% to 80% gains 36 kWh; at 90% efficiency the billed estimate is 40 kWh.
Units are part of the calculation. Enter a value together with its actual compatible unit; changing only the label does not convert it. The canvas converts results to the shown units. No exchange-rate table is needed for this single-currency example.
60 [Capacity kWh] × (80 [Target SOC]% - 20 [Start SOC]%) → Battery added kWh
Battery added kWh/90 [Efficiency]% → Billed energy kWh
Billed energy kWh × 0.2 [Tariff USD/kWh] → Energy charge USD
Energy charge USD + 1 [Session fee USD] → Session total USD
Change one input
Raise target charge from 80% to 90%. Battery energy rises from 36 to 42 kWh; billed energy and energy charge increase. The fixed fee stays unchanged.
| Result | Default | Changed |
|---|---|---|
| Battery added (kWh) | 36 | 42 |
| Billed energy (kWh) | 40 | 46.67 |
| Energy charge (USD) | 8 | 9.33 |
| Session total (USD) | 9 | 10.33 |
Results are displayed to at most two decimal places; later formulas use unrounded values.
Scope and limits
- 0 ≤ start SOC ≤ target SOC ≤ 100; efficiency must be above 0 and at most 100.
- Efficiency relates the billing point to energy stored in the battery.
- Capacity must be positive; tariff and fixed fee must be nonnegative.
Displayed charge percentages and usable capacity are approximate. Do not apply charging loss again if your energy figure already measures billed kWh. Idle fees, time-based charges, changing tariffs and charger installation are excluded. A fixed fee is still added even when no energy is added; set it to zero if no session charge applies.
Download and import into Calvance to edit the numbers. The canvas does not reject every invalid input; check the stated ranges.
Common questions
Is efficiency the same as loss percentage?
No. Enter 90 for 90% efficiency, not 10. The model divides by 0.90; simply adding 10% to battery energy gives a different result.
Does this predict charging time?
No. Charger power, the vehicle’s charging curve and temperature affect time. This canvas estimates energy and cost only.
References
FuelEconomy.gov · Where the Energy Goes: Electric Cars
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How to import your template
We recommend using the latest version of Calvance.
- Save the file. Choose Download template and save the .calvx file to Files on your iPhone or iPad. From a computer, you can send it to your device with AirDrop.
- Open Import. In All Canvases in Calvance, tap the add button to open the template screen, then choose Import.
- Choose the file. Select the saved .calvx file to create your own canvas. Importing uses one canvas from your allowance.
- Edit and check. Check the results against the worked example, then add your numbers. Duplicate the canvas to keep different versions.
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