Formula E supplier Williams believes the criticism of its batteries is unfair, even though several drivers struggled with technical issues relating to the battery management system during last week's Putrajaya ePrix in Malaysia.
Most teams struggled with the 39-degree ambient temperature and high humidity in Malaysia on Saturday and the thermal management of the Williams Advanced Engineering battery played a major role throughout qualifying and the race.
During the race, Renault e.dams drivers Sebastien Buemi and Nicolas Prost were both hit with multiple problems, while Antonio Felix da Costa was also forced to stop on the track.
The common error message that drivers would see on their respective dashboards is a 'battery management system' error, but during an interview with Autosport, Williams' programme leader Gary Ekerold said such an error message doesn't necessarily mean a problem with a battery itself.
"It was a stretch for every aspect of the car," Ekerold told Autosport.
"That level of heat places the entire car under immense pressure and stress.
"The error that comes up on the steering wheel is a BMS error that protects the entire system on the car.
"That could be an error on any aspect and the battery will protect the car.
"The battery was never designed to run at 39 degrees ambient temperature. So we're already past that operating window.
"It wasn't designed to run at 170kW, it was designed to run at 133kW. So we're already past that operating window.
"Racing is about being on the limit and sometimes teams trip over the limit. That can affect any number of things.
"In terms of a fundamental design fault, that's certainly not the case."
Ekerold added that the Formula E teams will be given no advice on how to manage their cars should the races in Uruguay and Argentina take place in similarly hot conditions.
"No, in actual fact it's the contrary," added Ekerold.
"We can't share that.
"We can't share the ultimate level of data with teams because they need to learn this process and understand it themselves.
"It's part of running the cars. Some teams have an advantage because they understand the system better, that's what makes them different."