ANA (or JAL?) found the main battery miswired recently. Hopefully the FAA will determine the cause sooner than later. Their investigation of the electrical system started about a month and a half ago. The audit progress most likely will be part of the decision process on whether the proposed battery fix being presented today will be accepted.
"WASHINGTON – In light of a series of recent events, the FAA will conduct a comprehensive review of the Boeing 787 critical systems, including the design, manufacture and assembly. The purpose of the review is to validate the work conducted during the certification process and further ensure that the aircraft meets the FAA’s high level of safety.
“The safety of the traveling public is our top priority,” said U.S. Transportation Secretary Ray LaHood. “This review will help us look at the root causes and do everything we can to safeguard against similar events in the future.”
A team of FAA and Boeing engineers and inspectors will conduct this joint review, with an emphasis on the aircraft’s electrical power and distribution system. The review will also examine how the electrical and mechanical systems interact with each other.