Quoting keegd76 (Reply 239): Do Yuasa also supply the charging system for the battery? |
No, that's Securaplane, with some involvement from Thales although I'm not sure what their role is.
Moderators: richierich, ua900, PanAm_DC10, hOMSaR
Quoting spacecadet (Reply 247): Well, it may be what the design is supposed to do. It doesn't seem to be what it actually does. The battery in the ANA incident reportedly dropped to near zero voltage before it went belly up. "Unexpected drops" in voltage seems to be one of the big problems here. |
Quoting RottenRay (Reply 251): The ANA battery wasn't in use when this voltage glitch appeared, and therefore, wasn't connected to the load - you can't say that the load controller failed, as it wasn't in use. |
Quoting RottenRay (Reply 215): Merely repeating a convenient but incorrect number makes one sound hysterical and misinformed. |
Quoting flood (Reply 216): Looks like Boeing is going full steam ahead "It said it plans to manufacture between 635 and 645 Dreamliners by year-end" "Overall, Boeing says it plans to produce almost 61,000 airplans in 2013." |
Quoting rheinwaldner (Reply 219): I have no idea. |
Quoting ncfc99 (Reply 221): As far as I know, we don't know the different failure mode quantities |
Quoting tdscanuck (Reply 226): As far as damaged reputation, it's far too late for that. |
Quoting tdscanuck (Reply 226): They are investigated and there isn't a common cause. Running a battery down until it shuts off is not the same as it catching fire when it's not over-discharged. |
Quoting BoeingVista (Reply 236): This isn't what the article says, it say that "Most of the batteries were returned because they had run down so far that a low-voltage cutout was activated." it does not directly state why they ran down, so the question of why the batteries ran down is open. |
Quoting BoeingVista (Reply 236): Also a "sensible' design would maybe stop the drain before the batteries became unusable? |
Quoting BoeingVista (Reply 236): Plus you say I assign all of the battery changes to failure, you seem to assign all the changes to inadverant discharge, what about the others or are you maintaining that there were no unexpected failures? |
Quoting BoeingVista (Reply 236): Semantics but I'll give you that bricked may not be "damaged" as in dangerous though as the batteries are rendered unusable through some sort of cut out I don't think that "damaged" as in beyond repair is an unreasonable description. |
Quoting markalot (Reply 238): So there is protection placed on these batteries for certain conditions, and many of the batteries bricked because those conditions were met. What about batteries that came close but did not exceed those conditions? What about batteries that came really really close? |
Quoting keegd76 (Reply 239): Do Yuasa also supply the charging system for the battery? |
Quoting keegd76 (Reply 239): Having said that, what would happen if you tried to charge a 'bricked' battery? I'd imagine the design would prevent that but again I don't know. |
Quoting ncfc99 (Reply 240): From what I can gather from your posts, I have assumed the batteries would have more capacity than they do before they would 'brick' themselves to eliminate the chore of replacement. Sorry if I'm making you go in circles. |
Quoting cornutt (Reply 242): If I understood what I read up-thread, a battery that bricks itself can be restored to service by the manufacturer. So it's still useable; it just needs service. Kind of like an engine that has reached its TBO time. |
Quoting Shenzhen (Reply 243): Quoting tdscanuck (Reply 237): ..if you want to do anything, even something as simple as refuel, you need to power up at least one of the common computing resource (CCR) cabinets, since they host the fuel indicating system and fuel valve control. That means you power up the whole computer, it's associated cooling fans, the indicating system probes, and the power distribution units that power the probes and valves. You sure about this? All the control / indication is on the re-fuel panel. I could see the fuel quantity system, and a few valves and lights. |
Quoting Shenzhen (Reply 243): They also stated that there were no delays or cancellations, therefore the issues must have been discovered well before any scheduled departure (like when they tried to power the airplane). |
Quoting Stitch (Reply 244): As to why this must be done off the airplane, I expect it's a safety measure. It has been noted that once a Li-Ion battery has been deeply discharged, it is more susceptible to thermal runway when re-charged. A shop offers a more isolated environment should the battery enter thermal runaway and catch fire and you can more easily apply extinguishing agents to said fire in a lab than in the EE bays |
Quoting Stitch (Reply 244): I expect Boeing has published time limits for powering various functions off the battery based on the draw of those functions. |
Quoting Stitch (Reply 244): As such, it sounds like that in at least some cases, the aircraft support crew are not properly "minding the clock" and are exceeding these limits, with the result that the battery hits the threshold and the protection circuitry kicks in. |
Quoting PITingres (Reply 245): What you keep insisting, without any proof or reasonable basis as far as I can tell, is that these drained, shut-off batteries are permanently damaged. I don't think that is the case, from what Tom is saying |
Quoting PITingres (Reply 245): By the way, if you're saying that the battery should shut down the aircraft while there's still enough charge left to boot the system for ground power recharge |
Quoting PITingres (Reply 245): Now, if the design is such that the handler has no indication of battery level except for the airplane going dead, that's a different issue. |
Quoting Shenzhen (Reply 248): I don't really believe that re-fueling or towing is the main cause for battery replacements. I can't think of too many occasions when an airplane would be re-fueled without the airplane being powered |
Quoting Shenzhen (Reply 248): Towing, the brakes should really only be used once it is over, to set the parking break. |
Quoting tdscanuck (Reply 237): Quoting trex8 (Reply 232): And if they are running down "inadvertently" from things like fueling up causing drain charge as gauges light up, as cited in the article and then locking out, the electrical system should be designed to cut off the power before the battery drops that low The electrical system *is* designed to cut off the power before the battery drops that low. That's why they have to replace the battery if they run it down .I feel like this is going in circles...people demand that the system cut off the battery to prevent over-discharge, then complain when the over-discharge protection does its job and results in the battery being replaced. |
Quoting tdscanuck (Reply 226): You're running the causation chain backwards...the battery has finite capacity. If you run it down far enough that it's *going* to be rendered potentially unsafe by continued discharge, you stop discharging it. This was an explicit requirement of the FAA special condition for the battery in the first place. |
Quoting trex8 (Reply 255): Perhaps the issue is that the charging system on the two planes which had an incident were malfunctioning and the batteries were left in a dangerously under charged state where problems then arose. Also maybe they need to change the parameters as to what level it can be discharged to. |
Quoting FlyingAY (Reply 256): So what you are saying, this is not true what Seattle Times writes: "At that stage, the batteries, which cost about $16,000 each, are essentially dead and cannot be recharged." |
Quoting tdscanuck (Reply 254): You need power to release the brakes. Many SOP's also require that a towed airplane have position lights on, enough main deck lighting for the maintenance crew to see what they're doing (safety in an evacuation), and a VHF to communicate with the ramp. |
Quoting 7BOEING7 (Reply 260): Quoting Shenzhen (Reply 259): I would think it would be safer to have electrical or hydraulic power available (other then a battery or accumulator). The brakes are electric not hydraulic. |
Quoting RottenRay (Reply 222): Quoting rheinwaldner (Reply 219): So as a summary: 100 destroyed batteries because of over-discharging indicate a poor charger design and a wrongly dimensioned battery. I missed where there were 100 destroyed batteries, only that those which had been discharged past a certain level had to be returned as their safety interlock had made them inoperable. |
Quoting AeroWesty (Reply 223): Quoting rheinwaldner (Reply 219): So as a summary: 100 destroyed batteries because of over-discharging indicate a poor charger design and a wrongly dimensioned battery. You have to go back and read the Seattle Times article. It wasn't 100 destroyed batteries because of over-discharging. Many, many were disabled simply due to mechanics disconnecting the batteries improperly. |
Quoting AeroWesty (Reply 252): Could it be that whatever the battery was used for on the ground triggered a chain of events that simply took some time to show up as a threat to the flight? |
Quoting PlanesNTrains (Reply 253): Essentially, "we don't know". |
Quoting rheinwaldner (Reply 262): These batteries are essentially dead. It is written in the article with those words. |
Quoting rheinwaldner (Reply 262): So the article basically confirms that the battery lacks capacity for the given demand. Demand should include easily possible cases of handling errors. And the second thing comfirmed by the article, is that the charging system is not up to the job if it lets run the battery into locked mode jusgt because a fuel gauge stays lit. The BMS must remove the load from the battery before that happens. |
Quoting rheinwaldner (Reply 262): Quoting RottenRay (Reply 222): Quoting rheinwaldner (Reply 219): So as a summary: 100 destroyed batteries because of over-discharging indicate a poor charger design and a wrongly dimensioned battery. I missed where there were 100 destroyed batteries, only that those which had been discharged past a certain level had to be returned as their safety interlock had made them inoperable. These batteries are essentially dead. It is written in the article with those words. |
Quoting tdscanuck (Reply 254): Quoting BoeingVista (Reply 236): This isn't what the article says, it say that "Most of the batteries were returned because they had run down so far that a low-voltage cutout was activated." it does not directly state why they ran down, so the question of why the batteries ran down is open. I said they discharged in service...I have no idea how that conflicts with what you're saying or what the articles are saying. If you run the battery down (regardless of how or why), the low-voltage cutout activates to protect the battery. You have to swap it out with a good battery on the airplane...the low-voltage battery isn't damaged (that's why the cutout is there in the first place), you just can't recharge in on the aircraft. You need to recharge it on a bench somewhere. Quoting BoeingVista (Reply 236): Also a "sensible' design would maybe stop the drain before the batteries became unusable? It does. When you replace a battery due to low-voltage cutout, you run through the CMM procedures *off the airplane* to release the interlock, test, and recharge the battery. Then you put it back in service. It's the "off the airplane" part that, by design, forces you to replace the battery in the aircraft. Quoting BoeingVista (Reply 236): Plus you say I assign all of the battery changes to failure, you seem to assign all the changes to inadverant discharge, what about the others or are you maintaining that there were no unexpected failures? No, I'm not assigning all the failures to inadvertent discharge. Some were honest to god failure (unknown cause or symptom), two caught fires (widely reported), and a bunch were discharged and shut down as designed. The accusation that you've repeatedly made is that there were 100+ replacements and that this should have informed the safety decisions around the 2 fires...that only makes sense if you're attaching those replacements to the same underlying cause as the fires. |
Quoting rheinwaldner (Reply 262): So the article basically confirms that the battery lacks capacity for the given demand. Demand should include easily possible cases of handling errors. And the second thing comfirmed by the article, is that the charging system is not up to the job if it lets run the battery into locked mode jusgt because a fuel gauge stays lit. The BMS must remove the load from the battery before that happens. |
Quoting rheinwaldner (Reply 262): These batteries are essentially dead. It is written in the article with those words. |
Quoting trex8 (Reply 255): Perhaps the issue is that the charging system on the two planes which had an incident were malfunctioning and the batteries were left in a dangerously under charged state where problems then arose. Also maybe they need to change the parameters as to what level it can be discharged to. |
Quoting FlyingAY (Reply 256): Thank you for taking the time to answer me. So what you are saying, this is not true what Seattle Times writes: "At that stage, the batteries, which cost about $16,000 each, are essentially dead and cannot be recharged." |
Quoting Shenzhen (Reply 259): I may be wrong, but I think position lights are powered from the 115 volt bus, not the 28 VDC (don't have a clue for the 787). I think main deck lighting isn't on the 28 VDC buss either (most airplanes) |
Quoting AeroWesty (Reply 267): Okay, this sure made me blink. In the LA Times article regarding Boeing's fourth-quarter earnings call with analysts: "Boeing expects earnings this year to be $5 to $5.20 per share, with revenue of $82 billion to $85 billion. The company expects “no significant financial impact” from the 787 ongoing grounding." Source: Boeing says it will find cause of 787 problems, defends batteries |
Quoting spacecadet (Reply 247): My guess as a project manager - because that's the only way I know to approach this - is that in the absence of a "smoking gun", you're going to see strengthened containment, additional software and/or hardware safeguards in the charging system, and a redesigned lithium ion battery. It's not going to be one thing; it's going to be all of them. Boeing is probably in fact working on this right now, because there's no point waiting. No system is perfect even if it is working as intended; this is a chance for Boeing to further improve the entire battery and charging system. If the investigation drags on, Boeing can go to the FAA and say "look, we've redesigned all this stuff, we can demonstrate its safety" and maybe that will be enough to get the grounding lifted. |
Quoting trex8 (Reply 271): What did you expect them to say?? They said similar with the 737NG production issues 15 yrs ago. |
Quoting AeroWesty (Reply 274): Knowing how expensive warranty refits can be, I was expecting Boeing would take some hit for the costs involved, and begin to estimate those costs now. |
Quoting PlanesNTrains (Reply 253): Which I think apply to the vast majority of the dialogue here. Essentially, "we don't know". That's why the aircraft are grounded. That some people seem to want to see it one way or another is really irrelevant as in the end, "we don't know". |
Quoting AeroWesty (Reply 274): Quoting trex8 (Reply 271):What did you expect them to say?? They said similar with the 737NG production issues 15 yrs ago. That was prior to Sarbanes-Oxley, which came into effect in 2002. Even though I'm on the record that I expect most of the costs of the grounding for the airlines would be covered by insurance, and not become Boeing's responsibility, I was expecting that there'd be some thought given to an allowance for the obvious engineering costs to isolate the battery problem and its correction in both delivered and undelivered airframes. Knowing how expensive warranty refits can be, I was expecting Boeing would take some hit for the costs involved, and begin to estimate those costs now. |
Quoting rheinwaldner (Reply 262): So the article basically confirms that the battery lacks capacity for the given demand. Demand should include easily possible cases of handling errors. |
Quoting rheinwaldner (Reply 262): And the second thing comfirmed by the article, is that the charging system is not up to the job if it lets run the battery into locked mode jusgt because a fuel gauge stays lit. The BMS must remove the load from the battery before that happens. |
Quoting rheinwaldner (Reply 262): No, wonder Boeing seems to be more sorry about the impact to their bottomline, than about what they have delivered in the first place. |
Quoting rheinwaldner (Reply 262): I bet that saying up to very recent times, that they "believe" in the sound design of the aircraft will be very embarrasing once the root cause and the resolution will be clear. Not anticipating that root cause will not appear to come across as very competent I fear. |
Quoting RottenRay (Reply 266): A reporter with limited knowledge, or Tom, who lives and breathes Boeing. |
Quoting RottenRay (Reply 266): The TL;DR version - DON'T ASSUME THEY'RE DEAD, they might just be in a locked-out self-protection mode until a bench test can be performed prior to recharging. |
Quoting Stitch (Reply 269): The batteries cannot be recharged on the plane. The batteries can be recharged outside the plane. |
Quoting SonomaFlyer (Reply 272): So this leads us back to the fact it appears to be an issue as to the batteries on the JAL and NH aircraft. *The charging system did what it's supposed to regarding over/under charging |
Quoting SonomaFlyer (Reply 272): *Airlines will need to have spare batteries at their various stations in case replacement is warranted. That should be easy at hubs (such as LAX or IAH for UA) but not at outlying stations such as LOS when UA begins service on the 787. |
Quoting SonomaFlyer (Reply 272): Given how much this a/c relies on electric power for so much of its operation, tremendous demands are put on the batteries from time to time. |
Quoting SonomaFlyer (Reply 272): You'd think all of this was part of the design of the battery itself and perhaps its robust enough but additional work is likely needed to provide some further safeguards against thermal run away and beefing up containment. |
Quoting max550 (Reply 273): In my very limited experience with hybrid and electric cars I've never seen a lithium ion battery like this with such large cells packed so closely together. |
Quoting rheinwaldner (Reply 219): So as a summary: 100 destroyed batteries because of over-discharging indicate a poor charger design and a wrongly dimensioned battery. |
Quoting tdscanuck (Reply 237): Replaced != destroyed. According to the articles, most were pulled for expiration (not destroyed) or the low-voltage interlock cutting in to *prevent* them being over-discharged and destroyed (also not destroyed). |
Quoting AeroWesty (Reply 267): "Boeing expects earnings this year to be $5 to $5.20 per share, with revenue of $82 billion to $85 billion. The company expects “no significant financial impact” from the 787 ongoing grounding." |
Quoting starrion (Reply 277): More that two years... then it would appear that SOX is mostly toothless. |
Quoting tdscanuck (Reply 270): Quoting trex8 (Reply 255): Perhaps the issue is that the charging system on the two planes which had an incident were malfunctioning and the batteries were left in a dangerously under charged state where problems then arose. Also maybe they need to change the parameters as to what level it can be discharged to. That's certainly a possibility, although I think the FAA/NTSB said they found no fault with the charger |
Quoting abba (Reply 279): No matter what (we do not need to spilt hair here) - is this indicative of a deeper design flaw? The designers not knowing precisely how much power the systems will need to draw from the batteries in normal operation? |
Quoting tdscanuck (Reply 284): It's possible that the field procedures take more time than expected, so they're not getting the airplane onto other power sources, in which case it's a design flaw but not one that could have been known in advance... |
Quoting JerseyFlyer (Reply 196): Intuitively this makes sense. An explanation from Boeing for their choice of eight large cells when presumably they discounted options comprising larger numbers of smaller cells would be of interest. |
Quoting AeroWesty (Reply 199): When you say "over discharge", is your meaning discharging too quickly or discharging below a certain value, or both? |
Quoting max550 (Reply 218): think he might be on to something. With about 2,400 Tesla Roadsters on the road I can't find a single report of a fire involving their li-ion battery. |
Quoting PlanesNTrains (Reply 253): That some people seem to want to see it one way or another is really irrelevant as in the end, "we don't know". |
Quoting abba (Reply 279): No matter what (we do not need to spilt hair here) - is this indicative of a deeper design flaw? The designers not knowing precisely how much power the systems will need to draw from the batteries in normal operation? |
Quoting AirlineCritic (Reply 276): Here's one theory. Batteries get bricked by the boatloads in the field, Boeing applies a software change to the shutdown safety limit to reduce the bricking, no one realizes that under some special conditions that new limit is actually not conservative enough, ANA and JAL happen to hit those special conditions and their batteries burn. |
Quoting AirlineCritic (Reply 276): Boeing applies a software change to the shutdown safety limit to reduce the bricking, |
Quoting rcair1 (Reply 286): Intuition is not always right. Perfect example - "intuitively" a quad should be more reliable than a twin. But - what we see populating the skys is a bunch of large twins. What you have is 2 big engines instead of 4 smaller ones. Reliability is one of the factors driving that. That may or may not translate to LiIon cells perfectly, but it is not intuitive. |
Quoting tdscanuck (Reply 237): The electrical system *is* designed to cut off the power before the battery drops that low. That's why they have to replace the battery if they run it down .I feel like this is going in circles...people demand that the system cut off the battery to prevent over-discharge, then complain when the over-discharge protection does its job and results in the battery being replaced. |
Quoting Shenzhen (Reply 264): If the battery no longer provides any power to the airplane because it turned itself off doesn't mean it is dead at the component level, but certainly when looking at the overall airplane system, as it no longer provides power to the airplane. example.... was late today because my battery died. Oh, how did you get here? I charged it. |
Quoting scbriml (Reply 265): It is clear that batteries in this state are unusable, but not damaged. They can easily be returned to service, but have to be removed from the plane to do so. |
Quoting RottenRay (Reply 266): The TL;DR version - DON'T ASSUME THEY'RE DEAD, they might just be in a locked-out self-protection mode until a bench test can be performed prior to recharging. |
Quote: Boeing officials said the need to replace the batteries also suggested that safeguards were activated to prevent overheating and keep the drained batteries from being recharged. Company officials said the batteries can drain too deeply if left on without being connected to power sources. Trying to recharge such batteries could generate excessive heat, so safety mechanisms lock out any attempts to do that. |
Quote: Kelly Nantel, a spokeswoman for the National Transportation Safety Board, said investigators had only recently heard that there had been “numerous issues with the use of these batteries” on 787s. She said the board had asked Boeing, All Nippon and other airlines for information about the problems. “That will absolutely be part of the investigation,” she said. |