@syseng68k (if I had a name like yours it would end with 6502)
I'm referring to Boeing's latest statements on the batteries. There's no quibble with the design choice of Li-ion, despite all the scaremongers there aren't any insoluble technical problems and in a few years we'll be wondering what all the fuss was about. My point was just that if the batteries were simply reserve power banks then an interim replacement with Ni-Cds to get the planes flying again should have been the first option. This seems to indicate a more fundamental reason for the choice (probably on the A350 as well).
My second comment was based on the expected result that nothing was found wrong with either the batteries or the chargers. Expected because given the quality of the engineers (a bit of irony in my post there, as a sop to those wo think anything not Boeing shouldn't be in the air) I'm sure that both the batteries and the electronics are top-notch. So the reason for the failures, catastrophic or otherwise, must be elsewhere.
Given the novelty of the design, there are bound to be unknowns in the entire system even if the individual components are well understood. What margins were taken by the system integrators? Did Boeing construct a full-scale replica of the electrical system (as the Concorde engineers did with their fuel system) or was it all simulated? What were the inputs to the simulations? I think that these are the sort of questions that should be asked.