A concerning rumor about the Porsche Taycan surfaced last week, and if proven true, has the potential to kill the car off completely.

According to Teslarati, who has a source within Porsche's headquarters in Zuffenhousen in Germany, six out of ten Taycans delivered have a battery management problem. The whistleblower also says that it damages the battery cells to the extent that it causes fires. The only unexplained Taycan fire we've reported on so far happened in February 2020, but battery electric vehicles don't have the best reputation in this department.

It goes even further than that. The source also says that Porsche is deliberately covering up the problem, replacing the batteries on cars without informing customers.

According to the whistleblower, the reason for this is the Taycan's 800-volt onboard charger. It allegedly does not control the charging process well enough, leading to the overcharging of some cells. An overheated cell is hazardous, but the Porsche will detect it and automatically shut it down. This reduces performance and range, however.

The whistleblower decided to speak up when Porsche decided to continue shipping the Taycan with the faulty charging system. The unknown source cites Porsche's own internal statistics that keep track of problems for safety reasons. According to these internal figures, around 1% of the 60% of vehicles with this problem had a preventable vehicle, cable, or smoldering fire that is directly related to the problem.

Porsche is allegedly aware of the problem but has thus far not informed customers or authorities about it. No whistleblower is needed to understand why Porsche might be hiding this problem. If it happens to be accurate, it will result in a massive recall. And as Chevrolet knows, replacing the battery pack of a BEV is a highly costly exercise. The whistleblower says the recall would cost hundreds of millions, damaging the Taycan's reputation beyond repair.

Allegedly, Porsche has the option of fitting a more sophisticated charger from the same supplier for around $70 extra, but has decided against it. The choice not to go for the more expensive unit is driven by targets costs and bonuses.

Finally, the source says that all Porsche dealers are under a strict NDA (non-disclosure agreement) and are told to label cars into three categories. A green car needs a repair, a yellow car needs a review with Porsche's internal technical department, and a red car needs a battery replacement. The source states that not all owners of red cars are informed that the battery has been replaced.

The NHTSA opened a Taycan investigation in May this year, but that was for a loss of power without any warning. The whistleblower does mention the above as a symptom, but the NHTSA has a loss of power listed as one of the recalls for the 2020 and 2021 models. According to the information on the NHTSA website, it's due to a software error, and the fix is to reprogram the power electronics and the engine control unit.