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Batteries Used On Previous Generation Aircraft  
User currently offlineBreninTW From Taiwan, joined Jul 2006, 1720 posts, RR: 1
Posted (1 year 11 months 1 week 2 hours ago) and read 4344 times:

I'm curious, it seems to me that the major problem with the 787 is the Li-ion batteries that have been used.

What type of batteries were used in previous generations of aircraft? I'm assuming they weren't lead-acid batteries, but were they Li-ion?

I work in the computer industry, so I'm fairly familiar with the problems encountered with shipping Li-ion batteries ... it seems counter-intuitive to me (as a rather ignorant outsider) to use the same type of battery on a passenger aircraft when the jolly things are are not allowed to be transported on passenger flights.

I understand that aviation-grade Li-ion batteries are almost certainly more thoroughly tested and manufactured under much stricter oversight than computer-grade batteries, but it's still surprising to me.

EDIT: Grammar correction.

[Edited 2013-01-16 21:36:47]


I'm tired of the A vs. B sniping. Neither make planes that shed wings randomly!
25 replies: All unread, showing first 25:
 
User currently offlinefr8mech From United States of America, joined Sep 2005, 5653 posts, RR: 15
Reply 1, posted (1 year 11 months 1 week 2 hours ago) and read 4346 times:

Batteries used on transport category aircraft (B787 aside) are almost exclusively Ni-Cad.

Quoting BreninTW (Thread starter):
it seems counter-intuitive to me (as a rather ignorant outsiders) to use the same type of battery on a passenger aircraft when the jolly things are are not allowed to be transported on passenger flights.

Not a rare issue on aircraft. O2 bottles, fire bottles, batteries and a few other things can't be shipped, but are installed on aircraft.



When seconds count...the police are minutes away.
User currently offlineBreninTW From Taiwan, joined Jul 2006, 1720 posts, RR: 1
Reply 2, posted (1 year 11 months 1 week 2 hours ago) and read 4326 times:

Quoting fr8mech (Reply 1):
Batteries used on transport category aircraft (B787 aside) are almost exclusively Ni-Cad

Thanks for that.

Any chance of the 787 switching back to Ni-Cad?



I'm tired of the A vs. B sniping. Neither make planes that shed wings randomly!
User currently offlineMir From United States of America, joined Jan 2004, 21864 posts, RR: 55
Reply 3, posted (1 year 11 months 1 week 2 hours ago) and read 4325 times:

We've got a lead-acid on ours (a Citation). There's also an option for a NiCad battery.

-Mir



7 billion, one nation, imagination...it's a beautiful day
User currently offline1337Delta764 From United States of America, joined Oct 2005, 6646 posts, RR: 2
Reply 4, posted (1 year 11 months 1 week 1 hour ago) and read 4320 times:

So, what about NiMH? They offer somewhat more capacity than NiCad, though not as much as Li-ion.


The Pink Delta 767-400ER - The most beautiful aircraft in the sky
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 5, posted (1 year 11 months 6 days 19 hours ago) and read 4212 times:

Quoting BreninTW (Thread starter):
I work in the computer industry, so I'm fairly familiar with the problems encountered with shipping Li-ion batteries ... it seems counter-intuitive to me (as a rather ignorant outsider) to use the same type of battery on a passenger aircraft when the jolly things are are not allowed to be transported on passenger flights.

The major difference between transport and use is the conditions of the installation...for installed stuff, you can put on containment, isolation, detection, and sometimes supression. For the cargo holds (i.e. shipped) you can only do detection and, maybe, suppression. You have a lot less control over what happens in the event of a failure, so the safety fault tree is a lot different.

Quoting BreninTW (Thread starter):
I understand that aviation-grade Li-ion batteries are almost certainly more thoroughly tested and manufactured under much stricter oversight than computer-grade batteries, but it's still surprising to me.

It's similar to how you can't ship jet fuel but you can stuff the airplane full of it.

Tom.


User currently offlinerfields5421 From United States of America, joined Jul 2007, 7607 posts, RR: 32
Reply 6, posted (1 year 11 months 6 days 17 hours ago) and read 4184 times:

Quoting 1337Delta764 (Reply 4):
So, what about NiMH? They offer somewhat more capacity than NiCad, though not as much as Li-ion.

From Wikipedia, which I know can be a problem on some subjects, but is usually very good with actual facts.

Quote:
The significant disadvantage of NiMH batteries is the high rate of self-discharge; NiMH batteries lose up to 20% of their charge on the first day and up to 4% per day of storage after that


User currently offlinenomadd22 From United States of America, joined Feb 2008, 1899 posts, RR: 0
Reply 7, posted (1 year 11 months 6 days 16 hours ago) and read 4150 times:

NiMh are also harder to properly charge, particularly that last 10%. We regret getting them because of the self discharge problem. We either have to pull out and charge hundreds of them every month, or they're useless when we need them.
They're not anywhere near as bad as Wiki says, but a lot worse than other types.
NiCads have the same problem with swelling and overheating when you overcharge or overuse them, but they don't go nuclear like Lithiums can.



Andy Goetsch
User currently offlineAirframeAS From United States of America, joined Feb 2004, 14150 posts, RR: 24
Reply 8, posted (1 year 11 months 6 days 15 hours ago) and read 4094 times:

Quoting BreninTW (Reply 2):
Any chance of the 787 switching back to Ni-Cad?

I don't think the 787 ever had Ni-Cad batteries to begin with.



A Safe Flight Begins With Quality Maintenance On The Ground.
User currently offlineStitch From United States of America, joined Jul 2005, 31409 posts, RR: 85
Reply 9, posted (1 year 11 months 6 days 14 hours ago) and read 4088 times:
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Quoting BreninTW (Reply 2):
Any chance of the 787 switching back to Ni-Cad?
Quoting AirframeAS (Reply 8):
I don't think the 787 ever had Ni-Cad batteries to begin with.

Correct. The same Li-Ion battery is used for both the main and APU battery (so that if the main battery goes MEL, you can install the APU battery in it's stead).


User currently offlineCALTECH From Poland, joined May 2007, 2319 posts, RR: 26
Reply 10, posted (1 year 11 months 6 days 14 hours ago) and read 4050 times:

As told to us, a NiCad battery with the power available to be used on the 787 would weigh 300+ lbs, a monster. Add the identical APU battery, as Tom/tdscanuck stated elsewhere, and that is some serious weight there. A 777 NiCad battery weighs about 106 lbs. The 787 LiIon battery weighs a mere 66 lbs. It more than likely that the LiIon battery is here to stay for some other issues as well. The APU battery is like a onboard spare for the main battery.


UNITED We Stand
User currently offlinekanban From United States of America, joined Jan 2008, 3857 posts, RR: 27
Reply 11, posted (1 year 11 months 6 days 13 hours ago) and read 4030 times:
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posted this question on the other thread.. maybe it more appropriate here

Yuasa makes these batteries for many land surface operations, trains, trucks, etc. and seem to have no problems. Possibly could the problem be related to the pressure differentials when flying... ie water boils at a lower temperature at elevation, so could the organic fluid in these batteries "boil" at altitude and leave the anodes/cathodes bare and in contact?


User currently offlineCALTECH From Poland, joined May 2007, 2319 posts, RR: 26
Reply 12, posted (1 year 11 months 6 days 4 hours ago) and read 3805 times:

Quoting kanban (Reply 11):
posted this question on the other thread.. maybe it more appropriate here

Yuasa makes these batteries for many land surface operations, trains, trucks, etc. and seem to have no problems. Possibly could the problem be related to the pressure differentials when flying... ie water boils at a lower temperature at elevation, so could the organic fluid in these batteries "boil" at altitude and leave the anodes/cathodes bare and in contact?

No, sure it was tested depressurized at altitude. And this electrolyte is more of a paste than liquid. But it probably does 'boil' during a thermal runaway.



UNITED We Stand
User currently offlinenomadd22 From United States of America, joined Feb 2008, 1899 posts, RR: 0
Reply 13, posted (1 year 11 months 6 days 4 hours ago) and read 3791 times:

Anything on a plane needs to be rated for the pressure it's operated at. And, since all the 787 batteries aren't in flames, it's obvious something is different with the ones that were. I'd bet dollars to doughnuts that it turns out to be a Yuasa quality control issue. Something as simple as not having series cells well enough matched. Hopefully, something that can be temporarily fixed by a monthly PM or whatever until the permanent fix is in.


Andy Goetsch
User currently offlineprebennorholm From Denmark, joined Mar 2000, 6538 posts, RR: 54
Reply 14, posted (1 year 11 months 6 days 3 hours ago) and read 3789 times:

Quoting CALTECH (Reply 10):
As told to us, a NiCad battery with the power available to be used on the 787 would weigh 300+ lbs, a monster.
Quoting CALTECH (Reply 10):
The 787 LiIon battery weighs a mere 66 lbs.

There is something wrong with these numbers. Power density on Li-Ion compared to Ni-Cd is in the 2.5 to 3 factor frame. So a potential 787 Ni-Cd battery would be like 165 - 200 lbs. Still an unpleasant addition, which has to be multiplied by two since there are two batteries.

Quoting rfields5421 (Reply 6):
The significant disadvantage of NiMH batteries is the high rate of self-discharge; NiMH batteries lose up to 20% of their charge on the first day and up to 4% per day of storage after that

That disadvantage is in many cases compensated by the higher power density compared to Ni-Cd.

But for use on airliners Ni-MH is irrelevant because they perform extremely badly when cold. For starting an APU on a frosty morning they would have to be crazily oversized. All batteries perform worse at low temperature, but Ni-Cd and Li-Ion (also lead acid) lose performance at low temperature at a much lower rate than Ni-MH.

Ni-MH still maintains the capacity at low temperature. But it has a very high voltage drop when high power output is required at low temperature.



Always keep your number of landings equal to your number of take-offs, Preben Norholm
User currently onlinerwessel From United States of America, joined Jan 2007, 2411 posts, RR: 2
Reply 15, posted (1 year 11 months 5 days 23 hours ago) and read 3707 times:
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Quoting prebennorholm (Reply 14):
There is something wrong with these numbers. Power density on Li-Ion compared to Ni-Cd is in the 2.5 to 3 factor frame. So a potential 787 Ni-Cd battery would be like 165 - 200 lbs. Still an unpleasant addition, which has to be multiplied by two since there are two batteries.

I don't understand the application well enough, but Li-Ion's have a rather flatter discharge curve down to their "knee" and the knee tends to happen a bit further down the discharge graph. You might need ~20% more nominal capacity in a NiCd if you need to keep the voltage up.


User currently offlineCALTECH From Poland, joined May 2007, 2319 posts, RR: 26
Reply 16, posted (1 year 11 months 5 days 16 hours ago) and read 3599 times:

Quoting prebennorholm (Reply 14):
There is something wrong with these numbers. Power density on Li-Ion compared to Ni-Cd is in the 2.5 to 3 factor frame. So a potential 787 Ni-Cd battery would be like 165 - 200 lbs. Still an unpleasant addition, which has to be multiplied by two since there are two batteries.

What's wrong with the numbers told to us by the manufacturer ? A 777 battery weighs in at 106 lbs and the 787 needs a battery that has approximately 3 times the stored power of the 777 as relayed to us by the manufacturer.



UNITED We Stand
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17172 posts, RR: 66
Reply 17, posted (1 year 11 months 5 days 7 hours ago) and read 3448 times:

Quoting CALTECH (Reply 16):
What's wrong with the numbers told to us by the manufacturer ? A 777 battery weighs in at 106 lbs and the 787 needs a battery that has approximately 3 times the stored power of the 777 as relayed to us by the manufacturer.

That's because the 787 is "all electric" with no bleed air system. It needs way more battery power as backup.

BTW does the 787 have electric engine start since it has no pneumatics?



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineFabo From Slovakia, joined Aug 2005, 1219 posts, RR: 1
Reply 18, posted (1 year 11 months 5 days 5 hours ago) and read 3414 times:

Quoting Starlionblue (Reply 17):
BTW does the 787 have electric engine start since it has no pneumatics?

Yes.



The light at the end of tunnel turn out to be a lighted sing saying NO EXIT
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17172 posts, RR: 66
Reply 19, posted (1 year 11 months 5 days 5 hours ago) and read 3394 times:

Quoting Fabo (Reply 18):
Quoting Starlionblue (Reply 17):
BTW does the 787 have electric engine start since it has no pneumatics?

Yes.

Run by the APU I guess. But still explains the beefy batteries.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineCALTECH From Poland, joined May 2007, 2319 posts, RR: 26
Reply 20, posted (1 year 11 months 4 days 17 hours ago) and read 3296 times:

Quoting Starlionblue (Reply 17):
BTW does the 787 have electric engine start since it has no pneumatics?

Yes, and as we are told, one can start both engines at the same time unlike most 'bleed air' transport aircraft.



UNITED We Stand
User currently offlineTristarsteve From Sweden, joined Nov 2005, 4068 posts, RR: 33
Reply 21, posted (1 year 11 months 4 days 14 hours ago) and read 3235 times:

Quoting CALTECH (Reply 20):
Yes, and as we are told, one can start both engines at the same time unlike most 'bleed air' transport aircraft.

Who told you that?
To start a B787 engine you need all the power from both APU generators, or Three Ground Power Units.
I suspect there is some way you can isolate this so that the APU supplies one side, and the 3 GPUs supply the other, but I wouldn't expect anyone to do it. Mainly because that when the engine is running, you then have to go and remove the GPU that is plugged into the AFT EE bay, behind the engines.
Not something I would recommend.


User currently offlineCALTECH From Poland, joined May 2007, 2319 posts, RR: 26
Reply 22, posted (1 year 11 months 4 days 5 hours ago) and read 3075 times:

Quoting Tristarsteve (Reply 21):
Who told you that?.

Our glorious Training Instructors as told from Boeing.

Quoting Tristarsteve (Reply 21):
To start a B787 engine you need all the power from both APU generators, or Three Ground Power Units. I suspect there is some way you can isolate this so that the APU supplies one side, and the 3 GPUs supply the other, but I wouldn't expect anyone to do it. Mainly because that when the engine is running, you then have to go and remove the GPU that is plugged into the AFT EE bay, behind the engines.
Not something I would recommend.

Incorrect.

As from Boeing and my manuals,

http://www.boeing.com/commercial/airports/acaps/787sec5.pdf

"Normal engine start for the 787 uses the APU to provide electrical power. If the APU is inoperative or unavailable, an engine start can be accomplished using a minimum of two 90 kVA external ground power units connected to the two forward external receptacles. Boeing recommends using three 90 kVA ground power sources to minimize the effect on cabin load shedding of ventilation, In Flight Entertainment, and cabin lighting."

Minimum of 2 X 90 kVA power sources for 180 kVA per engine. The third External Power pickup is for faster starts and minimize load shedding. Simultaneous engine start needs minimum of 360 kVA. Each APU generator has a rating of 225 kVA for a total of 450 kVA, more than enough for a simultaneous engine start. Unless, of course, Boeing and our Training Instructors have it wrong.

http://www.boeing.com/commercial/aer...rticles/qtr_4_07/article_02_4.html

"The power source for engine starting may be the APU generators, engine-driven generators on the opposite side engine, or two forward 115 VAC ground power sources. The aft external power receptacles may be used for a faster start, if desired."

At about 1:35, both engines seem to be turning, simultaneously.

http://www.youtube.com/watch?v=hLummpF9DHo

This one shows it really good in fullscreen 1080P hd.

http://www.youtube.com/watch?v=2Q6AEkpNtiU

This passenger says it also on a United Flight,

http://forums.vwvortex.com/showthrea...First-flight-on-the-787&p=79998410

"We pushed back and started up. The start sequence is something I've never experienced. They start both engines simultaneously (like the 777) but there is a lot of vibration, I'm guessing with them being a little out of sync, that you get about a minute long full body massage. The engine noise is non existent though."

When I was checking out the 787 Simulator, we also did simultaneous engine starts. Would say my outstanding training is correct, both engines can be started simultaneously.   

[Edited 2013-01-19 18:21:44]


UNITED We Stand
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 23, posted (1 year 11 months 3 days 1 hour ago) and read 2834 times:

Quoting Starlionblue (Reply 17):
That's because the 787 is "all electric" with no bleed air system. It needs way more battery power as backup.

It's not directly because of the all-electric architecture, because the things that used to be pneumatic but are now electric aren't using battery power anyway. It's mostly because the 787 avionics and fans need more juice to run (this would have been true with or without the pneumatic system).

Quoting Starlionblue (Reply 17):
BTW does the 787 have electric engine start since it has no pneumatics?

Yes. The drive the generators backwards as starters.

Quoting Tristarsteve (Reply 21):
Quoting CALTECH (Reply 20):
Yes, and as we are told, one can start both engines at the same time unlike most 'bleed air' transport aircraft.

Who told you that?

Boeing. I've seen it many times, in both the sim and the real aircraft.

Quoting Tristarsteve (Reply 21):
To start a B787 engine you need all the power from both APU generators, or Three Ground Power Units.

No. To start one engine you need one APU generator or two GPUs. Having more will make the start go faster and cause less load shedding but it will start just fine. If you want a simultaneous start you need both APU generators (one to each engine).

Tom.


User currently offlinekalvado From United States of America, joined Feb 2006, 497 posts, RR: 0
Reply 24, posted (1 year 11 months 1 day 7 hours ago) and read 2627 times:

Not exactly on topic - but are (were) there any plans to retrofit older types with Li batteries? I am thinking mostly narrow-bodies, where certification costs can be spread between many frames.
I can see that envisioned as a low-hanging fruit to save a few pounds of weight once first battery and enclosure design is certified with 787 and most issues are worked out. Apparently such projects would be put on hold with latest 787 problems, but would that make any sense to begin with?


User currently offlineCALTECH From Poland, joined May 2007, 2319 posts, RR: 26
Reply 25, posted (1 year 10 months 4 weeks 1 day 16 hours ago) and read 2512 times:

Quoting kalvado (Reply 24):
Not exactly on topic - but are (were) there any plans to retrofit older types with Li batteries? I am thinking mostly narrow-bodies, where certification costs can be spread between many frames.
I can see that envisioned as a low-hanging fruit to save a few pounds of weight once first battery and enclosure design is certified with 787 and most issues are worked out. Apparently such projects would be put on hold with latest 787 problems, but would that make any sense to begin with?

Probably not as the certification costs probably outweigh the cost savings. These batteries are very expensive right now.



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