The Securaplane fire was a clear warning
@hetfield & @syseng68k re. your posts 54 & 55 this thread:
Electronic tech Leon was fired by Securaplane after he blew the whistle to the FAA that this battery/charger assembly was unsafe for use in an aircraft. A US Department of Labor Administrative Law Judge's report found Leon's firing justified, but the story it tells leaves lots of reason to wonder if this technology was adequately vetted before it flew.
My post #37 earlier in this thread provides a link to the ALJ's report that provides additional detail beyond what was cited from Plane Talking.