Mercedes Traces 'Very Painful' Reliability Failures to Battery Module Issues

Mercedes has traced the "very painful" reliability failures that cost George Russell and Kimi Antonelli in recent races to problems within the battery module. Technical director James Allison confirmed the team understands the root cause and is preparing fixes.

Russell retired from the lead in Canada, while Antonelli dropped out of second in Barcelona with three laps remaining. Customer teams including McLaren have also suffered early setbacks under the 2026 regulations.

Why it matters:

With Mercedes leading both championships, unnecessary DNFs risk letting Ferrari back into the fight. Allison said the failures stem from the same broad area of the battery, making a targeted cure essential as the development race intensifies.

The details:

• Battery root cause: Allison explained the DNFs "originate in the same broad part of the battery," which the team calls the "module." Most risk areas have now been identified.
• Short-term safeguard: Mercedes has taken a "half step backwards," running components slightly less aggressively to build resilience while a permanent solution is proven out.
• Proper cure: Engineers are designing out the vulnerability so the power unit can be pushed to the limit again without race-ending failure.
• Ferrari's surge: Ferrari brought a major upgrade to Spain and dominated in Barcelona, with Lewis Hamilton winning by 19.6 seconds. Allison noted that under these young regulations, a big upgrade is worth roughly the gap Mercedes held at the season's start.

What's next:

Mercedes heads to Austria leading the constructors' standings by 72 points, with Antonelli 41 points clear of Hamilton. Allison is confident the team's development slope is steep enough to re-establish its advantage once its own upgrades arrive. The priority is ensuring the reliability fixes land before another costly DNF erodes that buffer.