(株)ジーエス・ユアサ コーポレーション【6674】の掲示板 〜2015/04/27

もうボーイングもユアサもすまんが救えないな
http://seattletimes.com/html/businesstechnology/2020241385_787deadbatteriesxml.html
“We have had at least 100, possibly approaching 150, bad batteries so far,” the person said. “It’s common.”
Most of the batteries were returned because they had run down so far that a low-voltage cutout was activated.

The design of the 787’s electrical system includes a battery switch in the cockpit. But even when that main switch is off, the battery comes on when certain ground tasks are performed.

Just as a car’s dome light will come on even when the ignition is off, drawing power from the battery, so too on an airplane certain maintenance tasks will bring the battery to life.

For example, if an airline mechanic puts jet fuel in the wing gas tank when the airplane is otherwise dark, as soon as the fuel door opens the battery will begin to provide power for the gauges that measure the fuel levelThe 787 batteries are unique and the system supplier, Thales of France, insists that the original manufacturer — its subcontractor GS Yuasa — must be the sole supplier.
So all the dead 787 batteries have been shipped back to Japan and replacements have had to be sent from there..

If that door latch is not properly closed or if the mechanic encounters a problem or leaves something else open too long, the 787 battery can drain down below the critical 15 percent level in an hour, the person said.