When Charging An EV, A Significant Amount Of Energy Is Lost

The Swiss automobile club TCS has investigated the energy efficiency of electric cars on chargers and found that, on average, 11 percent of the energy consumed is lost. In other words, 1,637 kilometers of paid range are lost annually, per vehicle and at prices in Switzerland.

TCS has now examined the energy efficiency of electric cars during charging in detail, with worrying results. Data collected between 2022 and 2025 shows that on average, 11 percent of the energy consumed is lost when charging with standard 11 kW wall boxes, which many electric car drivers use. Extrapolated to an annual mileage of 15,000 kilometers, this corresponds to a range of 1,637 kilometers, which are paid for but lost and unused.

TCS and its partners tested 26 electric vehicles with less than 30,000 kilometers. The amount of energy entering the vehicle from the power grid was compared with the energy that can later be used from the battery. The measurements were also carried out at temperatures of around 23 degrees, i.e., under conditions in which batteries should work particularly efficiently.

Data estimated by TCS gives an average overall efficiency of 89 percent.

Interestingly, there were significant differences between individual vehicle models. The overall efficiency of the electric models tested ranged from 84 to 93 percent. Or, converted into range, a loss of 1,087 to 2,359 kilometers per year. Despite this study and the losses when charging electric cars, TCS emphasizes that in practice, electric vehicles still achieve significantly higher overall efficiency than comparable vehicles with internal combustion engines.

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