saptzae:
Clear to me, two PCB's for exactly that purpose in the box. The upper
for control and monitoring. The lower for balancing.
Not convinced :-). Normally, in projects where there is a mix of digital
and measurement quality analog electronics, the analog and digital
sections are separated onto separate pcbs, or the analog sections are
enclosed in screening cans to reduce digital noise. That would suggest
that the board nearest the cells is for the analog and the lower board
handles the digital. The fact thet there are several larger pin count
devices on the lower board suggests digital logic, possibly memory or
microprocessor class devices.
The other point is w/regard to the bypass, where worst case of 10w per
cell needs to provided for. Even using switch mode tech, you still
have to dissipate that power somewhere and there's little evidence of
parts to do this on the boards.
Still, the monitoring should see and log all abnormal conditions and
fire off warnings before batteries fail.
Agreed - the data log for the battery would be logically the first place
to look for the events that led to the failure, but where is it and
why wasn't this escalated back up the chain to Boeing ?. Such a
battery replacement rate should have been noticed at some level...
Regards,
Chris