After weeks of unexplained breakdowns, Mercedes believes it has found its culprit — and it sits inside the battery. The team says a single area of its power unit is behind the failures that robbed George Russell of a Canadian Grand Prix win and Kimi Antonelli of a Barcelona podium, and a permanent fix is now on the way.
The run of misfortune has been hard to watch. Russell was leading in Canada last month when his car simply stopped. Then, at Barcelona, championship leader Antonelli was holding second behind Lewis Hamilton when his engine expired with three laps left. The 19-year-old admitted to feeling "emotionally empty" once the dust settled — and his title cushion took a hit at the worst possible time.
Mercedes technical director James Allison, speaking on the team's Nu Silver Arrows Radio Show, confirmed the retirements were related. "I think anyone who's a keen watcher of the sport will have seen that this has laid a few Mercedes engine cars low over the season so far," he said. "They're not all identical, but they do sort of originate in the same broad part of the battery."
Encouragingly, Allison says the team has now got its arms around the problem. "I think that most of the areas of risk have been understood. And with a bit of luck, when we start to sort of phase in the new modules into the racing season — we call the battery 'the module' — then our fortunes as a fleet should pick up." The stakes, he made plain, are high: "These DNFs are very, very painful."
Allison was refreshingly honest about how a team with Mercedes' resources keeps tripping up. The philosophy, he said, is to break components on the test bench, never on a Sunday. "You accept that there will be failure. We try to make sure that failure happens in testing or on rigs and that it happens as little as possible when you're out there trying to earn championship points." When a car does stop on track, he conceded, "that is definitely a failure of our process."
The trouble has not been confined to the works cars. Customer team McLaren has battled its own electrical headaches — Lando Norris required a battery change at Monaco before retiring with a power-unit issue, and both Norris and Oscar Piastri were sidelined before the Chinese Grand Prix even started by separate electrical faults. Whether those share the module Allison describes is unconfirmed, but it shows how far a single weakness can ripple across an engine supplier's customers.
Team boss Toto Wolff had already set expectations in the immediate aftermath of Barcelona, stressing that Mercedes cannot afford this kind of unreliability in a title fight and pledging to "leave no stone unturned to understand" the cause. Allison's diagnosis is the first hard answer to that vow.
What happens next is delicate. Antonelli leads, but Russell and a rejuvenated Hamilton are within striking distance, and one more failure could reshape the championship. Mercedes must now introduce the redesigned module quickly enough to halt the losses — without inviting a new problem under championship pressure. For a team whose reputation was built on bulletproof reliability, this stretch has been a genuine wake-up call.
