The "APU" Battery, and the "MAIN" Battery. These are misnomers.
Each Battery system is a group of eight separate batteries. Each battery has three cells.
The Eight Batteries are connected in series and contained in a Stainless Steel enclosure.
It is not possible to "isolate" one battery from its seven sisters. To do so interrupts the series.
One bad battery, no more "group". IF the system works correctly.
I hope I have that right, I have been referring to the Back up power system that way since the outset.
For whatever reason the nomenclature took that turn, it misleads. "Ah, just the one "cell", then, not so bad...." Any problem with one of the eight batteries disables the entire back up system. That is a game changer, appearance-wise.
The ANA Captain reported a "zero Voltage". As if that is an anomaly?
That is not an anomaly, that is the design. And it frames the dependability of the flight critical system as suspect.
Last edited by Lyman; 15th Feb 2013 at 12:29.