On Mar 24, 1:50*pm, Joe Gwinn wrote:
I just read the 18 March 2013 issue of Aviation Week. *On pages 28-29,
there are two articles on the 787 battery investigation results and
proposed fixes.

What caught my eye, and apparently that of the investigators, was that
there was never an all-up test of the 787 battery charging system with
the actual Yuasa-made production battery. *They were tested
independently, but there is no record of them ever being tested
together.

Anyway, the fixes are basically to isolate the cells better so if one
self-destructs, it cannot take the other cells with it, venting of
smoke overboard, better electrical insulation all around, and a lot of
black-box data recording so they can figure out root cause next time.

Joe Gwinn

http://www.aviationweek.com/Article....AW_03_18_2013_
p28-559071.xml

It's good that they are keeping the problem contained, but it doesn't
seem to address the issue of removing heat generated by the
batteries. They are asking a 30V battery about twice the size of a
car battery to start an 1100 hp APU (genset) and not get excessively
hot. Internal resistance always gets worse in a battery. (I'll bet
that the mgt system for cell charging won't be the issue.) I don't
know why space is so tight that they cannot spread the 8 cells apart
and have proper heat sinks for them.