Will put my 2 cents in here,
Batts no matter what type are just a storage device.
For example your car, rated at 12 volts, batt is 12 volts, the charging current going into the batt is 13.5 to 14 volts.
Depending on the state of discharge and governed by the voltage regulator.
You would never get a fully charged batt with just a 12 volt charge going into it, has to be higher.
12 volts is already considered 50 percent discharge.
On the 747 batt voltage is 32-36 represents a normal batt charge.
The apu batt is only used during apu start, but has a lower voltage requirement on pre flight.
The main ships batt is always lower because it is wired to the hot battery bus and always has a discharge , clocks etc.
Just wondering if this main ships batt is very low and not being charged as much due to short flights, maybe overheatingtrying to make up for the loss, a sponge even though dry can only soak up so much water a a time will will try to take as much as it can.
If you overcharge or exceed it it will boil over.
Sorry just and old F/E and thoughts.
Thats why the smoke and mirrors replaced us,
They know best.

Investigation focus 'is now on the battery charger and APU':

BBC News - US widens Dreamliner safety probe after battery finding

Dendritic
 

Look into lithium dendritic structure. Microscopic anneal process.:8

But what's the big deal?Incident: ANA B788 near Takamatsu on Jan 16th 2013, battery problem and burning smell on board The battery is smaller than the car battery. Just put any other type. Will be twice as big but who cares? Can be done in couple of hours.

Turbavykas, that is without doubt my favourite PPrune post ever. How soon can you be in Seattle?

You're welcome to him in Seattle. We certainly don't want that sort of genius here in Europe. Shame we can't shed these non aviation types, or that they don't care to learn from ppr.:ugh::ugh:

have to agree also.
stick the old proven types back in and get the airplane back in the air.
Not much difference in the weight, retire a few grandma F/A. at united.
Even lesser weight reduction
Batts weigh less .

BRILLIANT!!

I nominate the Baghdad battery. Nothing like returning to old technology to get a tried and tested outcome!

The Baghdad Batteries

The charger and battery protection systems need to be matched with the battery cell technology, so unless that already supports a different cell chemistry (eg NiMh or NiCad) then no you can't just fit a different battery tech in a few hours. There are likely to be other issues as well. Is there an NiMH pack available with all the same connectors/signals in the right places?

from an earlier post...

So it's not charged in flight either? There have been cases of Li batteries combusting when not in use, sometimes weeks after the original damage occured but this wasn't a Li Manganese cell technology.

Another question?
 

Didn't Boeing have an in flight fire on the Dreamliner during flight testing and if so does anyone know if it was battery related?

Don't think this was battery related..

Boeing: 787 fire caused by failure in aft electronics bay power panel | ATWOnline

RR NDB

check this

Li-polymer Battery: Substance or Hype?

To my knowledge, the 787 LiIon are cobalt based.

So, the scaring vid I posted is not toooo off...:*
Regards

Another relevant article on battery technology:

Boeing’s Dreamliner batteries “inherently unsafe”

If it is only battery safety that is concerning the FAA, I wonder if replacing the Yuasa battery with an equivalent SAFT Li-ion unit would work as an interim 'fix' to get the 787 fleet in the air again.

SAFT seem to have a good safety and reliability record in the supply of LI-ion batteries for use in space vehicles. For this application, they must be capable of withstanding mechanical stresses during launch and a wide temperature range during orbit. Safety features on individual SAFT cells include a shutdown separator, a circuit breaker, a vent and a stainless steel outer case. A SAFT battery, comprising a number of individual cells, is then encased in a further stainless steel container.

See link: http://www.saftbatteries.com/doc/Doc...e4af5b011d.pdf

Any more on the previous report that the APU battery charger takes it's supply off the F/O's Instrument supply bus?

Yeah, I shook my head too when I read it.........they wouldn't would they...:hmm:

From a post by gas path in http://www.pprune.org/rumours-news/5...arning-12.html

post 224


So the possibility, however slight, of a cascading battery failure [s] dragging down the supply buss[es] for both "sets" of instruments?

that can't be right surely.....:(

Can I just clarify some confusion in my head? There are two batteries per plane, is that right? One for the APU and one for the rest of the plane's electrical requirements? The various battery problems encountered in the 787 involve both the APU battery and the main ship battery, yes? Are these both Li-ion and made by Yuasa? And are they both physically in the same electronics bay?

There are two batteries per plane, is that right?
Yes

One for the APU and one for the rest of the plane's electrical requirements?
Yes

The various battery problems encountered in the 787 involve both the APU battery and the main ship battery, yes?
Yes

Are these both Li-ion and made by Yuasa?
Cells (Li-Ion) are made bei Yuasa, Batteries are labled "THALES"

And are they both physically in the same electronics bay?
No, main batt in fwd E/E, APU batt in aft E/E compartement.

If this is a repost, please erase. Look at pic #2, about 1/3 down this page:
Dreamliner Fire: Investigation Widened

See my modified post 238 above..............

glad rag

Don't worry, if a battery :mad: up, the relevant charger will not affect its supply bus.