Inquiry expands into Boeing Dreamliner batteries

The National Transportation Safety Board will now have to look for a new cause of the battery problems plaguing the Boeing 787 Dreamliner after ruling out "excess voltage". 

The NTSB released an update of its investigations into the Dreamliner battery on Sunday, saying that the lithium-ion battery that caught fire on a parked Japan Airlines jet earlier this month "did not exceed its designed voltage," reports the Wall Street Journal. 

Japanese investigators looking into why a second lithium-ion battery malfunctioned aboard an All Nippon Airways flight on January 16 originally though the battery may have been overcharged. 

Pilots aboard the flight to Tokyo noticed a burning smell and instruments on the Dreamliner indicated a battery error. The plane made an emergency landing in Western Japan.

More from GlobalPost: Japanese airlines ground Boeing 787s after more problems

Japanese airlines ANA and Japan Airlines grounded all of their Dreamliner jets after the incident.  

Previously released images show that both batteries were heavily charred, according to the Wall Street Journal. The Federal Aviation Administration said both batteries leaked electrolyte fluid and caused smoke damage to nearby portions of the aircraft.

Reuters reports that investigators will fly to Arizona on Tuesday to start looking into the company that manufacturers the chargers used for the Dreamliner's batteries.  

Shubhayu Chakraborty, president of Securaplane, did not comment to Reuters about the visit but said the company would support the investigation. 

"At this time we are not really involved in the investigation. If and when we get involved, we will support it fully," he told Reuters.

The NTSB said investigators will test and examine the battery charger, and download non-volatile memory from the APU controller starting on Tuesday. Other components have been sent to Boeing's Seattle facility and manufacturer facilities in Japan to be examined. 

Transportation Secretary Ray LaHood said the Boeing 787 would remain grounded until regulators were "1,000 percent sure" it was safe to fly, reports Reuters.