Formula E title contender Lucas di Grassi rued a debilitating problem with his battery during the first phase of the London ePrix in Battersea Park on Saturday.
The re-generation power diminishes at a certain temperature when the battery heats up and affects the braking of the Formula E car.
The earlier it reaches the critical temperature point, the slower the car goes. This is what made di Grassi pit earlier than planned and hampered his race in London today.
“It was the same as what happened to me in Moscow, the battery overheated,” di Grassi told Motorsport.com. “We knew it was the same battery so we had to be conservative.
“I had energy to go two laps longer, but I had to stop because of temperature and it messed up my strategy. I had to save a lot of energy and that is why Jean-Eric [Vergne] was right on me and got through.
“There is a limit with the temperature where the battery just shuts down and so you can’t go too far over the limit because the more you run the faster the battery heats up.
“It is a problem where we cannot do anything, as we are obliged to start with the same minimum temperature so there is no fix and the team cannot do anything better.”
Piquet v di Grassi duel continues
One of the most thrilling moments of the race came early in the race when di Grassi was forced to defend from a charging Nelson Piquet Jr, the points leader.
The smouldering feud between the title rivals looked set to be re-ignited, but both saw it as more of an inevitability that contact would be made due to the tight confines of the Battersea Park track.
“I knew he had the fan-boost and he would use it and as I was slow,” di Grassi told Motorsport.com.
“I stayed on the inside and he tried to squeeze me over as little, we touched but I had the inside and I braked normally and didn’t even cut the chicane because of it. I think it was fair attack and a fair defence so no problems for me.”
When Piquet used his fan boost to draw alongside Di Grassi contact was made between the pair pushing Piquet slightly wide
“I would have done the same as him in defending but I had to try and pass, whether it was over, under, outside, whatever,” said Piquet.
“He defended normally so it was just a case of doing what I could. It is easy to defend here because of the lack of room and the bumps, it is just super tough to make a clean pass."
The antipathy between the Di Grassi and Piquet stretches back many years to when they were competing in karting together.
Vastly different characters, the two have never really got on and the fight for the first FIA Formula E Championship title tomorrow could underline the trash talk from earlier in the week.