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Search: Posts Made By: saptzae
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4th May 2013, 18:16
Replies: 50
Views: 23,916
Posted By saptzae

??????? ????? ?????? ???????? ??? ?? ????? ??????...

??????? ????? ?????? ???????? ??? ?? ????? ?????? - YouTube

Edited Google translation of description on video:
Forum: Tech Log
25th Apr 2013, 15:29
Replies: 72
Views: 18,235
Posted By saptzae

@mm43 I doubt they production test at 4.55V...

@mm43

I doubt they production test at 4.55V Per cell, as it would do irreparable damage and set cells up for failure within a short time - seconds - thereafter.

Actually, FDR at BOS shows...
Forum: Tech Log
16th Mar 2013, 06:47
Replies: 1,100
Views: 174,433
Posted By saptzae

@rottenray I second your post in its...

@rottenray

I second your post in its entirety.

Talking is just so much easier than understanding.

I read sites like pprune and avherald pretty much since their beginnings. Read, to learn....
Forum: Tech Log
12th Mar 2013, 18:34
Replies: 1,100
Views: 174,433
Posted By saptzae

@kenneth house Hull and eebay is at...

@kenneth house


Hull and eebay is at cabin altitude ~6000 feet
Cells are derated to 4.025V / ~80%SOC
BCU was not connected to charger / test rig at 2006 incident
OV/UV is being considered...
Forum: Tech Log
11th Mar 2013, 16:08
Replies: 1,100
Views: 174,433
Posted By saptzae

@Lyman I really do not understand your last...

@Lyman

I really do not understand your last two posts. All was discussed already.


No, there are 8 cells containing each 3 sub-cells, or elements in NTSB speak.


Not relevant. Cells are...
Forum: Tech Log
11th Mar 2013, 12:09
Replies: 1,100
Views: 174,433
Posted By saptzae

The main battery at BOS shows cell deterioration,...

The main battery at BOS shows cell deterioration, as per CT report.

The NTSB battery block diagram does not show cell balancing.

I was thinking that the block diagram is simplified. Perhaps...
Forum: Tech Log
11th Mar 2013, 04:31
Replies: 1,100
Views: 174,433
Posted By saptzae

@Lyman A cell can be managed to not short. BTW,...

@Lyman
A cell can be managed to not short. BTW, a cup of coffee can be managed to not spill or burn its contents consumer.

Link to exponent paper?

I have not read the materials report yet, it...
Forum: Tech Log
10th Mar 2013, 22:50
Replies: 1,100
Views: 174,433
Posted By saptzae

@Lyman I apologize for explaining things...

@Lyman
I apologize for explaining things poorly. You help me to manage my posts better. Thank you.

By "Management" I refer to action it takes, to meet the objective of reliable and safe...
Forum: Tech Log
10th Mar 2013, 19:37
Replies: 1,100
Views: 174,433
Posted By saptzae

@FlightPathOBN Yes, there is so much to learn...

@FlightPathOBN
Yes, there is so much to learn about this wonderful airplane.

When all this is over, the entire industry will have progressed substantially.
Forum: Tech Log
10th Mar 2013, 19:24
Replies: 1,100
Views: 174,433
Posted By saptzae

@Ian W Well, the securaplane lab building...

@Ian W
Well, the securaplane lab building burned down once while testing (without BMU connector plugged in) :{

Seriously, they surely did not test a cell to failure inside an airframe, nor with...
Forum: Tech Log
10th Mar 2013, 18:47
Replies: 1,100
Views: 174,433
Posted By saptzae

A single cell (blade) failure can be contained. A...

A single cell (blade) failure can be contained. A multi cell failure (hub) is hard to contain.

Thus am I most concerned about fixing the Primary cause and preventing the Secondary and Tertiary...
Forum: Tech Log
10th Mar 2013, 13:57
Replies: 1,100
Views: 174,433
Posted By saptzae

@Lyman I am fairly confident about causes of...

@Lyman
I am fairly confident about causes of cascading - Secondary and Tertiary - failures. Known?, Not yet. Lets say we are on a good track to understanding.

Yes, upon remedy after gaining...
Forum: Tech Log
10th Mar 2013, 06:27
Replies: 1,100
Views: 174,433
Posted By saptzae

Further to my post 857:...

Further to my post 857: http://www.pprune.org/7731615-post857.html

Three possible explanations for the 45A into the battery from 10:21:04:
a) Likely: that the charger commenced fast charging at...
8th Mar 2013, 18:43
Replies: 2,186
Views: 899,240
Posted By saptzae

@fgrieu The Root cause - of the...

@fgrieu



The Root cause - of the Primary failure (cell short) - remains undetermined, without any tangible progress apparent.

The state of damaged batteries precludes determination of the...
Forum: Tech Log
8th Mar 2013, 15:34
Replies: 1,100
Views: 174,433
Posted By saptzae

After cell failure, 45A went into the battery for...

After cell failure, 45A went into the battery for 3 seconds and triggered remainder of the mess.

Timely disconnection is key after a cell failure. Within 10-20 milliseconds that is. Faster would...
Forum: Tech Log
8th Mar 2013, 03:44
Replies: 1,100
Views: 174,433
Posted By saptzae

Confirmed no NVM / no logging of details. ...

Confirmed no NVM / no logging of details.

Scenario:


10:21:01 Primary failure - cell short of #3



10:21:04 Secondary failure - Large current (45A) for 3 seconds overcharging and...
Forum: Tech Log
4th Mar 2013, 19:58
Replies: 17
Views: 5,149
Posted By saptzae

http://www.pprune.org/tech-log/350693-vref-landing...

http://www.pprune.org/tech-log/350693-vref-landing-4.html#post4566320
28th Feb 2013, 22:27
Replies: 2,186
Views: 899,240
Posted By saptzae

OT

@llagonne66
Thank you, the Flight blogger link you provided, links to an interesting article The Seattle Times: Making It Fly (http://seattletimes.com/news/business/757/) on the 757 cert effort,...
Forum: Tech Log
28th Feb 2013, 05:59
Replies: 1,100
Views: 174,433
Posted By saptzae

Derated

Cells are derated to 4.025V EOC, or about 70%-80% of max charge at 4.2V.

Consumer or EV batteries will charge to 4.1 - 4.2V.

The difference in reliability is huge. 0.1V reduction quintuples...
27th Feb 2013, 23:11
Replies: 2,186
Views: 899,240
Posted By saptzae

RAT

Main bat is needed for brakes after touchdown.

@Golf-Sierra
Sounds reasonable.

For inflight needs, the RAT will suffice.
http://farm8.staticflickr.com/7024/6790408327_e78df195c1_b.jpg
B787...
Forum: Tech Log
27th Feb 2013, 05:30
Replies: 1,100
Views: 174,433
Posted By saptzae

LiCoO2 is mature technology. These cells are...

LiCoO2 is mature technology. These cells are derated to 4.025V EOC and ultra reliable.

There is too much damage to the cells. It is improbable, that the cause of the Primary failure can be...
Forum: Tech Log
21st Feb 2013, 15:55
Replies: 1,100
Views: 174,433
Posted By saptzae

@SoS Right, and the BMU will hopefully disable...

@SoS
Right, and the BMU will hopefully disable the charger.

For this scenario, the parasitic source - main bat bus -> switch -> nav light -> switch -> APU bat - remains, feeding the APU bat.
...
Forum: Tech Log
21st Feb 2013, 09:48
Replies: 1,100
Views: 174,433
Posted By saptzae

@fizz57 Concur, by connecting to NAV lights...

@fizz57

Concur, by connecting to NAV lights from two sources, such as main bat bus and APU battery, there may be a parasitic current path into APU battery, bypassing the intent of the design.
...
Forum: Tech Log
21st Feb 2013, 05:20
Replies: 1,100
Views: 174,433
Posted By saptzae

Secondary failure

@RR_NDB
A direct connection, feeding current into a battery with a failed cell, would drive good cells into runaway by overvoltage.

There should be no paralleling of battery to battery or...
Forum: Tech Log
20th Feb 2013, 18:16
Replies: 1,100
Views: 174,433
Posted By saptzae

@RR_NDB Yes, as we see only effects of Tertiary...

@RR_NDB
Yes, as we see only effects of Tertiary failures, which destroyed all evidence of degradation leading to the Primary failure.



6 Tertiary failure symptoms (heat, fire)

5 Tertiary...
Showing results 1 to 25 of 93
 


 
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