- Mercedes links repeated race retirements to a battery module fault in its power unit.
- Two DNFs have cost the team an estimated 43 points across Canada and Barcelona.
- New battery modules are in development, but no timeline has been confirmed.
Mercedes has traced a string of race retirements this season to a fault inside its power unit battery, and the team is now preparing replacement modules to prevent further failures.
The confirmation came from technical director James Allison after Kimi Antonelli’s car lost all electrical power while running second at the Barcelona Grand Prix last weekend, the second such retirement for a Mercedes-powered car in as many race weekends.
George Russell had suffered an identical shutdown while leading the Canadian Grand Prix the month before. Both drivers were left stranded at the side of the circuit, unable to do anything as their steering went dark.
The problem that keeps switching the lights off
Toto Wolff, the Mercedes team principal, offered his initial read on the Canada failure shortly after the race. “It looks like a module failure, so a battery failure, because the car was literally going back,” he told the media. “There was no electricity in the car anymore.”
The issue has spread beyond the factory team. Customer outfit McLaren has also dealt with a run of electrical trouble this season.
Lando Norris required a battery change during the Monaco Grand Prix weekend and retired from that race, with power unit settings given as the cause. Both Norris and Oscar Piastri had also failed to start the Chinese Grand Prix earlier in the season due to separate electrical faults.
The Chinese GP situation carried a lasting penalty for McLaren. Mercedes HPP could not repair one of the batteries damaged there, and Norris permanently lost one of his three permitted units for the entire season.
Allison reveals what Mercedes has found
After the team examined Antonelli’s car in Barcelona, Allison confirmed they had identified the common origin of the failures. He spoke about the findings on the Mercedes Nu Silver Arrows Radio Show.
“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,” Allison said via comments shared by Motorsport.com. “They’re not all identical, but they do sort of originate in the same broad part of the battery.”
New modules are being prepared and will be phased into the racing season. Allison was careful not to overstate the certainty of the fix.
“I think that most of the areas of risk have been understood,” he said. “And with a bit of luck, when we start to sort of phase in the new modules into the racing season, then our fortunes as a fleet should pick up.”
While the permanent solution is being developed, the team is running its equipment more conservatively. Allison explained the approach directly.
“The team will tend to take a slight half-step backwards to be more cautious with the equipment, to push it slightly less hard, just to give a little bit of resilience to the kit that’s obviously suffering,” he said. The goal, he added, is to protect vulnerable components in the short term while engineers work on a proper cure.
What this means for the championship fight
Seven rounds into the 22-race season, Antonelli leads the drivers’ championship with 156 points, 41 ahead of Ferrari’s Lewis Hamilton. Mercedes also leads the constructors’ standings with 262 points, 72 clear of Ferrari.
But those margins are smaller than they should be. The team estimates the two retirements in Canada and Barcelona cost it 43 points, setting aside the positions the other car gained after each failure.
Wolff made his concern clear after the Barcelona race. “We just can’t compete for a championship if every second race a car is losing fat points,” he told Sky Sports F1. “It’s one and then the other, and to finish first, first you have to finish. That’s just not good enough.”
He also flagged how quickly a DNF reshapes the picture. “You see a DNF robs you of 25 points, and it’s wide open,” he said. “That’s why we can’t afford to not finish.”
Ferrari’s Barcelona upgrade appears to have narrowed the performance gap between the two teams. Mercedes has not given a timeline on when the new battery modules will be ready.
The team now faces four races across five weeks, beginning with the Austrian Grand Prix, with no confirmed date for the fix and a championship lead it cannot afford to keep eroding.
