WASHINGTON (AP) — The battery that caught fire in a Japan Airlines Boeing 787 in Boston earlier this month was not overcharged, but government investigators said there could still be problems with wiring or other charging components.
An examination of the flight data recorder indicated that the battery didn't exceed its designed voltage of 32 volts, the National Transportation Safety Board said in a statement.
NTSB investigators are continuing to look at the battery system. They plan to meet Tuesday with officials from Securaplane Technologies Inc., manufacturer of the charger for the 787s lithium ion batteries, at the company's headquarters in Tucson, Ariz., said Kelly Nantel, a spokeswoman for the board.
"Potentially there could be some other charging issue," Nantel said. "We're not prepared to say there was no charging issue."
Even though it appears the voltage limit wasn't exceeded in the case of the Japan Airlines 787 battery that caught fire on Jan. 7 in Boston, it's possible that the battery failures in that plane and in an All Nippon Airways plane that made an emergency landing in Japan last week may be due to a charging problem, according to John Goglia, a former NTSB board member and aviation safety expert.
Too much current flowing too fast into a battery can overwhelm the battery, causing it to short-circuit and overheat even if the battery's voltage remains within its design limit, he said.
"The battery is like a big sponge," Goglia said. "You can feed it with an eye dropper or you can feed it with a garden hose. If allowed, it will soak up everything it can from the garden hose until it destroys itself."