George Russell’s MGU-K problem at Spa left the Mercedes driver more than 15 km/h slower than his rivals during the opening lap of the Belgian Grand Prix. The British driver’s deeply unfortunate weekend eventually ended without points following contact with Lewis Hamilton, but his race had already been severely compromised by an abnormal power unit issue immediately after the start.
With insufficient electrical energy available, George Russell’s MGU-K began reducing its power contribution much earlier than those of the cars around him. By the time he reached the Kemmel Straight, he had virtually no electrical assistance left and was unable to defend against the two Ferrari drivers.
George Russell’s MGU-K problem compounds contrasting Mercedes fortunes
Two completely different emotions now coexist inside Mercedes. On one side, there is the satisfaction of Andrea Kimi Antonelli, who claimed his sixth victory of the season and returned to the top step of the podium for the first time since Monaco. A series of unfortunate incidents during the previous races had prevented the Italian driver from achieving another victory sooner.
On the other side is the profound disappointment of George Russell, who leaves Spa-Francorchamps with no points and several unanswered questions. Before the Belgian Grand Prix, the British driver had admitted that one of his priorities was to adapt his driving style to the characteristics of the current Mercedes.
George Russell believes his approach is not yet perfectly suited to this generation of Formula 1 cars. Andrea Kimi Antonelli appears able to exploit certain aspects of the Mercedes more effectively, particularly on corner entry, where he can stabilise the rear of the car more efficiently.
However, as had already happened at Silverstone, power unit problems emerged again at Spa and led George Russell to reconsider part of his interpretation of the performance gap to his team-mate. Toto Wolff later acknowledged that a substantial part of the British driver’s qualifying deficit was caused by abnormal behaviour from the electric motor, which was not distributing energy correctly.
The issue provided further context to the straight-line time George Russell lost during qualifying at Spa. What initially appeared to be primarily a difference between the two drivers was also influenced by the operation of the Mercedes power unit.
George Russell says battery failure made the situation dangerous
These power units are proving extremely sensitive. As McLaren team principal Andrea Stella has also explained, teams can sometimes struggle to understand and identify the reasons for behavioural differences between engines, even when they are running extremely similar settings.
Those problems also had a negative impact on George Russell’s race from the moment the lights went out. Speaking after retiring following his collision with Lewis Hamilton, the Mercedes driver did not blame his fellow Briton for the contact, describing it instead as a racing incident. His frustration was directed at the lack of electrical energy available at the start.
“I made a good start. I got through Turn 1 well and was immediately behind Verstappen, but for some reason the battery decided not to recharge at Turn 1,” George Russell explained.
“The battery didn’t recharge and I came out of Turn 1 with a 35% deficit. And because it didn’t recharge, I also had a boost problem. The turbo didn’t spool up, so I had no power. I reached the top of Eau Rouge with the battery at 0%. Honestly, it was dangerous,” he added.
That situation was the main source of George Russell’s frustration after the race. The lack of power caused difficulties not only on the descent towards Eau Rouge but, above all, along the Kemmel Straight, where rival drivers passed him with ease because of the visible difference in speed.
George Russell was unable to defend even though he was receiving a small amount of slipstream from Max Verstappen ahead. The Mercedes driver simply did not have enough electrical energy available to sustain his acceleration.
Toto Wolff confirms energy problem affected every Mercedes power unit
The starting procedures required with these Formula 1 cars are particularly complex. At the Australian Grand Prix earlier in the season, several cars had arrived at the start without sufficient battery energy because of a calculation error.
For that reason, before the formation lap, George Russell was reminded to check that the state of charge, or SOC, was within the correct operating range once he reached his grid position. After the car had lined up, his race engineer confirmed that all the relevant parameters appeared normal.
Despite the correct SOC readings, Toto Wolff later explained that every Mercedes-powered car suffered an energy shortage on the exit of Turn 1. The problem affected George Russell more severely than Andrea Kimi Antonelli, although the eventual race winner was not completely unaffected.
“All the Mercedes engines had a lack of energy out of Turn 1,” Toto Wolff explained. “So it wasn’t only George. The problem affected him more than Kimi, but Kimi also suffered from it to some extent. That meant he didn’t reach the end of the straight in third position, but in fifth.”
The problem underlined why Toto Wolff had previously described Spa as a major energy-management test for Mercedes. The circuit’s long full-throttle sections can heavily punish any deficit in electrical deployment or energy recovery.
Why George Russell’s MGU-K began cutting power early
As George Russell explained, the car failed to recover enough electrical energy under braking for the first corner. Consequently, the Mercedes was already suffering from an energy deficit as it accelerated away from Turn 1.
The MGU-K was probably also unable to compensate adequately for the operation of the turbo, which in those conditions required support from the electric motor to provide the necessary boost pressure. Without that electrical contribution, George Russell was left with severely reduced acceleration.
Onboard footage clearly showed the extent of the problem. George Russell’s electric motor began reducing its power contribution immediately after Turn 1, well before the end of the pit-exit line and considerably earlier than the point at which the movable rear wing could be activated.
The system recognised that less energy was available and therefore entered its power-limiting phase far earlier than those of the surrounding cars. Among the leading drivers, George Russell was the person most heavily penalised by this behaviour.
Every other front-running car only began to experience MGU-K derating after passing the end of the pit exit and the rear-wing activation line. George Russell, by contrast, entered the limiting phase much sooner, compromising his acceleration throughout the entire run towards Eau Rouge.
The situation was particularly damaging on a circuit where straight-line efficiency was already a major technical consideration for Mercedes. Any interruption to electrical deployment was therefore magnified by the length and gradient of the opening full-throttle section.
George Russell lost more than 15 km/h on the Kemmel Straight
George Russell initially positioned his car cleverly to cover Charles Leclerc, limiting the Ferrari driver’s opportunity to attack before Eau Rouge. However, after climbing through Raidillon, the Mercedes driver should have been able to activate the boost function, release electrical energy and defend his position.
Instead, George Russell had virtually no tools available. Charles Leclerc and Lewis Hamilton both passed the Mercedes convincingly as its speed deficit became impossible to overcome.
Although George Russell was receiving a slight tow, he was more than 15 km/h slower than Lewis Hamilton, who was running alongside him. To place that figure into context, the difference was greater than the qualifying speed gap between Mercedes and Aston Martin.
That enormous deficit affected George Russell’s attempt to defend against both Charles Leclerc and Lewis Hamilton. His race later ended following the contact with the seven-time world champion, but the Mercedes driver’s opening lap had already been transformed by the MGU-K energy problem that left him powerless on one of the fastest sections of the Spa-Francorchamps circuit.
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