Charging losses: why billed kWh exceed battery energy
A charging session uses energy for more than storing it in the cells. Compare energy figures measured at the same boundary before interpreting a bill, consumption figure or battery test.
Stored energy is the energy added to the battery. Delivered energy reaches the vehicle and can include vehicle conversion losses and auxiliary use. Grid energy also includes losses on the supply side of the chosen measurement boundary.
In this guideChoose a section
01
Three different energy quantities
The electricity meter, charging point and vehicle may therefore show different values without any of them being a battery-capacity measurement. Temperature control and other vehicle systems can consume energy during charging.
02
Use efficiency as a fraction
Supply energy = stored energy ÷ efficiency. With 90% efficiency, storing 36 kWh requires 40 kWh from the supply: 4 kWh is not stored.
A 10% loss of the supply energy is not calculated by simply adding 10% to the battery energy.
For 8 kWh stored, the same assumption gives 8 ÷ 0.90 = 8.89 kWh drawn. At an invented €0.30/kWh, energy costs about €2.67. Efficiency varies with power, car, equipment and conditions; 90% is an illustrative assumption.
03
Do not add the same losses twice
A documented WLTP AC consumption figure already includes charging. If you use that figure to price energy per 100 km, multiply by the tariff directly. Do not increase it again for charging losses already included.
A net consumption estimate from driving needs a separate allowance when predicting the electricity bill. Actual billed kWh do not need the same allowance added again.
State the basis of each figure so that two cars or two charging methods remain comparable.
Likewise, the energy billed during a session is not a direct measurement of usable battery capacity or battery state of health. A proper test must specify its method and reference.
More examples and detail
Examples from the expanded catalogue
Compare the figures
Battery energy stored in the 20–80% window, before charging losses
Škoda Epiq 40 · Italy 2026
- Usable capacity
- 37 kWh
- Energy stored
- 22.2 kWh
Škoda Epiq 55 Selection · Italy 2026
- Usable capacity
- 51.7 kWh
- Energy stored
- 31.02 kWh
Suzuki e Vitara 61 kWh 2WD · Europe 2025
- Usable capacity
- ≈ 59.8 kWh
- Energy stored
- 35.88 kWh
Comparison from the table in this guide.
| Version | Usable capacity | Energy stored |
|---|---|---|
| Škoda Epiq 40 · Italy 2026 | 37 kWh | 22.2 kWh |
| Škoda Epiq 55 Selection · Italy 2026 | 51.7 kWh | 31.02 kWh |
| Suzuki e Vitara 61 kWh 2WD · Europe 2025 | ≈ 59.8 kWh | 35.88 kWh |
≈ marks an indicative usable capacity. Use the correct battery and source market. Model records include English technical notes and original source links.
Specifications refer to the version, year and market shown. Model records have English notes; original source documents may use another language. They do not certify current availability in your country.
05
Sources and method
English editorial version updated 16 October 2026. Arithmetic examples are Ricaora calculations. Efficiencies, consumption assumptions and example tariffs are not measured vehicle results or current commercial offers.
Installation requirements and electricity contracts vary by country; use qualified local advice for the electrical system.