Electric Car Charging Mega Test: Do EVs Really Charge as Quickly as They Say?

Charging speed is a crucial factor for EV owners, especially when time is of the essence. However, many motorists have found that their vehicles don't always charge at the advertised rates. The test at Gridserve's hub involved 10 different models, including the Tesla Model Y, Ford Capri, and Porsche Taycan, among others. Each car was put through its paces to determine how quickly it could charge from 20% to 80% capacity, and beyond. The conditions were controlled, with an ambient temperature of 13-14 degrees Celsius, and none of the cars were preconditioned before charging. This created a level playing field and mirrored real-world scenarios where drivers might not always prepare their vehicles for optimal charging conditions.

The test revealed significant disparities between the claimed and actual charging rates of many EVs. For instance, while the Ford Capri and Volkswagen ID.7 hit their peak charging rates quickly and maintained them for extended periods, other models like the Citroen e-C3 and Peugeot E-3008 struggled to reach their advertised speeds. The Citroen e-C3, for example, peaked at 69kW, well below its claimed 100kW, and took longer than expected to charge from 80% to 100%. Meanwhile, the Porsche Taycan, despite being one of the most advanced models, also failed to reach its claimed rate of 320kW, peaking at 282kW. These results underscore the variability in EV charging performance and highlight the challenges manufacturers face in meeting their own specifications.

One critical aspect affecting charging rates is the battery management system (BMS) employed by each vehicle. The BMS is responsible for regulating the charging process, taking into account factors such as battery temperature and state of charge. More sophisticated systems, like those in the Ford and VW models, use continuously variable algorithms to optimize charging speed, while others rely on simpler look-up tables that adjust rates based on fixed criteria. This difference in technology can lead to significant variations in charging performance. For instance, the Kia EV3 demonstrated a 'splash-and-dash' approach, maintaining high rates initially but dropping sharply as limits were reached. In contrast, the Renault 5, with its more advanced system, managed a smoother charge curve, though it still fell short of its maximum potential.

Another factor influencing EV charging is the state of charge at which the vehicle is plugged in. Generally, EVs charge faster when the battery is low and slow down as it fills up. This is because higher states of charge increase the risk of overheating and potential battery damage, prompting the BMS to reduce current flow. The BYD Seal exemplified this behavior, starting strong but tapering off significantly as it approached full capacity. Such behavior is common across most EVs, emphasizing the importance of charging strategy. For drivers, this means that topping up from 20% to 80% is often the most efficient use of public fast chargers, while charging beyond this point is best done at home, where time is less of a concern.

The test also highlighted the importance of preconditioning the battery before charging. Some manufacturers, like Tesla, suggest that preconditioning can significantly improve charging rates by bringing the battery to an optimal temperature. However, not all vehicles provide a manual option for this, and drivers may not always remember to activate it. The Tesla Model Y, for example, underperformed during the test, which Tesla attributes to the lack of preconditioning. This aspect underscores the need for better user education and more intuitive vehicle interfaces that guide drivers in maximizing their vehicle's charging potential.

Ultimately, the Auto Express test serves as a reminder that while EV technology has advanced significantly, there are still hurdles to overcome in achieving consistent and efficient charging. The discrepancies between claimed and actual charging rates highlight the complexity of EV systems and the need for transparency from manufacturers. For consumers, understanding these nuances can lead to more informed decisions and better management of expectations. As the industry continues to evolve, ongoing testing and consumer feedback will be crucial in driving improvements and ensuring that EVs meet the demands of modern drivers.