Boeing is running these 2-3 hours tests.
What they need to do is fly the 787 on a overseas flight, with all the electronics going full blast, tv’s and cooking appliances and the such, as in the real world. And weigh the plane down as if you have a full load of people, then fly halfway out into the Pacific and then return home. That will tell you more than these short-hop tests they are running.
Folks, you have the wrong impression of what these batteries are for. They are not used to run the entertainment and hospitality equipment. They are used to start the APU’s and in emergencies, the avionics.
They are the size of an old desktop PC.
With that said, from the photographs I’ve seen, these packs are poorly designed for use in aircraft:
1) The cells are not partitioned with a cooling system - Air or water jacket around each cell to prevent over or under heating.
2) The electronics in the pack are incorrectly supported for aerospace use - They are held via posts instead of frames and slots.
3) If dedrite growth is the issue, 2 - 3 hour flights will not cause a failure in the short term. Repeated, rapid charge and discharge cycles on a bench will cause the dendrite growth which will eventuall pierce the inter-layer membrain of an individual battery leading to thermal runaway.
Also, there’s way to much speculation being taken as fact here. Go to the NTSB web site and read the investigation reports for facts.
Also, let the engineers do their job. Time more than anything will find the source of this problem.
As an interm, Boeing can probably retrofit nickel metal hydride packs. This will require a recertificaiton of the aircraft however. Which can take months.