EV Charging Losses Compared: ADAC Test Reveals Efficiency Gaps in Five Popular Models

Five EV Models Put to the Test for Charging Efficiency

The German automotive club ADAC has released the results of a recent test on home charging efficiency for electric vehicles, uncovering substantial differences in energy losses across various models. The test included five popular EVs: the Mercedes-Benz CLA 350 with EQ Technology, Renault 5 E-Tech, Tesla Model Y, Volvo EX30, and Volkswagen ID.7. The findings show that when using a low-power mobile charger, some models experience energy losses as high as 24.2%, while switching to an 11 kW home charger can reduce losses to below 7%.

ADAC explained that during the charging process, an EV’s on-board charger converts alternating current (AC) to direct current (DC) to power the battery, a process that inherently results in energy loss. Additionally, electronic components such as temperature control systems consume power. To ensure accuracy, ADAC conducted the test with charging sessions limited to a state of charge between 10% and 90% and maintained the battery’s starting temperature between 68°F (20°C) and 86°F (30°C).

Wide Disparities in Energy Loss Among Models

The test results revealed that the Mercedes-Benz CLA 350 with EQ Technology experienced the highest energy loss, reaching 24.2% when using a 2.3 kW mobile charger, the worst performance among the five models tested. ADAC attributed this to an 8-ampere current limit imposed on the on-board charger when using a mobile charger, significantly reducing conversion efficiency. In contrast, the same model saw losses drop to 6.9% when using an 11 kW home charger.

The Tesla Model Y demonstrated lower losses, with 12.7% when charged at 2.3 kW and 6.1% at 11 kW, outperforming the other models. The Renault 5 E-Tech achieved the lowest losses at 5.1% when charged at 11 kW, making it the most efficient model in the test. While the Volvo EX30 supports 22 kW charging, the reduction in losses compared to 11 kW charging was minimal, dropping from 7% to 6.7%.

ADAC also simulated a 4.1 kW solar charging scenario, where losses ranged from 8% to 12.8% across the models, still higher than the efficiency achieved with an 11 kW home charger. The data confirmed that higher charging power generally results in lower energy losses, though the performance varied significantly among the models.

High-Powered Home Chargers Offer Long-Term Savings

ADAC recommends that EV owners use high-powered home chargers whenever possible, as these not only shorten charging times but also significantly reduce energy losses. For example, the Tesla Model Y’s losses dropped from 12.7% with a 2.3 kW charger to 6.1% with an 11 kW charger, nearly halving the energy waste. While high-powered chargers involve higher upfront installation costs, the long-term savings from reduced energy losses can offset the initial investment over time.

ADAC further noted that energy losses primarily stem from the efficiency of the on-board charger’s conversion process. Some automakers have begun adopting silicon carbide (SiC) semiconductors over traditional silicon components to improve conversion efficiency. Although SiC components are more expensive, they effectively reduce energy losses during charging, offering greater long-term economic benefits.

The test results serve as a reminder to consumers that when selecting charging equipment, the focus should not solely be on the initial purchase cost. Instead, evaluating long-term electricity expenses is crucial. While high-powered home chargers require a higher upfront investment, the reduction in energy losses can provide tangible economic benefits for EV owners over time.

EV Charging Losses Revealed: ADAC Test Highlights Efficiency Gaps Across Five Models

Five EV Models Put to the Test for Charging Efficiency

Wide Disparities in Energy Loss Among Models

High-Powered Home Chargers Offer Long-Term Savings

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