Mercedes finds battery fault behind title threat

Mercedes says it has traced the retirements hurting its Formula 1 title push to the battery area of its power unit, with technical director James Allison revealing after Barcelona that new modules are being phased in while the team works on a permanent fix.

The problem links the two most damaging failures for the works team so far this season. George Russell retired while leading in Canada, and Andrea Kimi Antonelli dropped out of the Spanish Grand Prix with five laps left after overtaking Russell for second place. Allison said on Mercedes' Nu Silver Arrows Radio Show that the failures were "not all identical" but "do sort of originate in the same broad part of the battery."

That diagnosis gives Mercedes a direction, but not much breathing room. Team principal Toto Wolff said after Barcelona that the points loss is already too severe for a championship campaign. "We just can't compete for a championship if every second race a car is losing fat points," Wolff told Sky Sports F1, before adding to media including Crash.net: "To finish first, first you have to finish."

Mercedes has already paid heavily for the issue. The two works-team retirements in Canada and Barcelona amount to a calculated 43-point loss, with Russell losing a likely 25 points and Antonelli another 18. Antonelli still leads the drivers' standings, but Ferrari's win in Spain cut his advantage over Lewis Hamilton to 41 points, while Mercedes' lead in the constructors' championship has been reduced to 72 points over Ferrari.

The concern stretches beyond the factory cars. Allison said "a few Mercedes engine cars" have been affected, and McLaren has also suffered electrical trouble this season. Lando Norris needed a battery change during the Monaco weekend and then retired from the race, while both Norris and Oscar Piastri failed to start in China with separate electrical issues.

Allison said Mercedes believes "most of the areas of risk have been understood" and expects "with a bit of luck" that "our fortunes as a fleet should pick up" as the updated modules arrive. He stressed there is still a process to follow when a weakness appears, with Mercedes first easing the load on the vulnerable hardware before producing what he called "a proper cure." Until that cure reaches the cars, the team remains exposed to exactly the kind of shutdowns that are turning a championship lead into a reliability fight.