Mercedes finally has a name for the gremlin that has been wrecking its title campaign: the battery. After two engine failures in three races cost George Russell a win in Canada and Kimi Antonelli a podium in Barcelona, the team says it has traced the retirements to a single area of its power unit and is building a permanent fix.
The pattern was impossible to ignore. Russell's car conked out while he was leading the Canadian Grand Prix last month. Then, last weekend, Antonelli — the championship leader — was running second behind Lewis Hamilton at Barcelona when his engine let go with three laps to run. The 19-year-old described himself as "emotionally empty" afterwards, a result that trimmed his lead at the worst possible moment.
Speaking on the team's Nu Silver Arrows Radio Show, Mercedes technical director James Allison confirmed the failures share a common root. "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."
Crucially, Allison believes the team now understands 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." He did not downplay the cost of getting it wrong: "These DNFs are very, very painful."
The Mercedes technical chief was candid about why a team of its resources keeps getting caught out. The aim, he explained, is to break parts on the bench rather than on a Sunday afternoon. "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," Allison said. When a car does stop, he conceded, "that is definitely a failure of our process."
It is a problem that reaches beyond the works cars. Customer team McLaren has endured its own run of electrical trouble: Lando Norris needed a battery change over the Monaco weekend before retiring with a power-unit-related issue, and both Norris and Oscar Piastri failed to start the Chinese Grand Prix with separate electrical faults. Whether those are linked to the same module Allison describes is unclear, but the spread underlines how costly a battery weakness can be across an engine supplier's fleet.
Team principal Toto Wolff had set the tone immediately after Barcelona, insisting Mercedes simply cannot carry this kind of unreliability into a championship fight and vowing to "leave no stone unturned to understand" what was going wrong. Allison's diagnosis is the first concrete answer to that promise.
The timing matters. Antonelli leads the standings but has a teammate in Russell and a resurgent Hamilton chasing hard, and a single further retirement could swing the title picture. Mercedes now has the harder task: phasing in the redesigned module fast enough to stop the bleeding without introducing a fresh problem under pressure. For a team that has built its modern identity on reliability, the run of failures has been a jolt — and Allison knows the fix has to land before the calendar punishes them again.
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