PPRuNe Forums - View Single Post - 787 Batteries and Chargers - Part 1
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Old 8th Mar 2013, 21:26
  #884 (permalink)  
Lyman
 
Join Date: Aug 2011
Location: Grassy Valley
Posts: 2,123
kiskaloo...

Almost all of the battery failures were caused by ground personnel running these functions off the batteries for longer than Boeing's guidelines called for. This caused the batteries to discharge to a state that tripped safety systems to prevent over-discharge and/or damage to the battery. Said batteries were removed from the plane, re-charged at the airline's maintenance facility or an appropriate MRO, and then returned to service.
Can you cite a source?

Also, once discharged, these batteries cannot be "recharged" according to Boeing...and Yuasa. There is no "return to service". My belief is that once discharged, the presence of dendrites makes them useless. And potentially dangerous.

Were the accident batteries in the "replacement group"?

Which frankly does not sound reasonable, just set the baseline charge state higher than FAIL. Let the lights go dark, ffs.

This is evidently a Boeing design philosophy. I have been informed that the 777's APU will also shut down if the APU battery fails and on the 767, turning the APU battery switch to the off position while on the ground will shut down the APU.
The introduction of Lithium Ion Batteries seems to have inspired another look at this "design philosophy"?

Last edited by Lyman; 8th Mar 2013 at 21:36.
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