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#221
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Is the 787 a failure ?
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| The letter from the NTSB signals tension between the agency | and Boeing. This is not good for Boeing, as it tries to | mitigate damage to the image of its high-efficiency 787 -- | that is, once officials clear the plane to fly. | | The main complaint from the agency appears to be that | Boeing representatives provided "their own analysis and | conclusions regarding an ongoing NTSB investigation," | according to Kelly Nantel, a safety board representative. | | Boeing representative Marc Birtel, meanwhile, responded to | the NTSB criticism -- saying the company officials | "received the correspondence, and remain fully committed to | support the NTSB and other regulatory authorities in their | investigations into the cause of the 787 battery incidents." | | In a related story from Reuters, Japan's Civil Aviation | Bureau said on Friday that, despite optimistic predictions | by Boeing, no test flight of the grounded 787 Dreamliner | has been scheduled yet. | ... http://money.msn.com/top-stocks/post.aspx?post=78e5846c-37f3-4e7f-a6d0-e07cdf584ce1 --bks |
#222
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Is the 787 a failure ?
On Fri, 22 Mar 2013 18:07:26 -0400, "Jim Wilkins"
wrote: "Daryl" wrote in message ... And you have NEVER seen an accidental leaking of an AGM battery. Now just admit it. Those that can: Do. Those that can't: Teach Daryl And those that are absolutely worthless, administrate. Stop trying to change your own conditions. I've seen one that HAD ruptured, but I wasn't watching when it happened. jsw |
#223
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Is the 787 a failure ?
On 3/22/2013 6:09 PM, GunnerAsch wrote:
On Fri, 22 Mar 2013 18:07:26 -0400, "Jim Wilkins" wrote: "Daryl" wrote in message ... And you have NEVER seen an accidental leaking of an AGM battery. Now just admit it. Those that can: Do. Those that can't: Teach Daryl And those that are absolutely worthless, administrate. I was stationed with a newly awarded BS in Electronics once. He was a 2 striper. He lorded over all the "Unclean and Uneducated" masses pretty hard. I finally shut him up by saying that he was an idiot before he was educated and now he was an ajumicated Idjit. The one that laughed the hardest at that was a buck sgt who was previously a Cornell University Professor who had joined the circus to get away. The Prof had a Masters and was one paper away from his PHD but you couldn't tell it. He was an alright person, really salt. We finally bugged, griped, threatened, etc. to get him to turn his paper in that he had already completed and he went back to Cornell with a full Professorship with his PHD. Daryl |
#224
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Is the 787 a failure ?
On Fri, 22 Mar 2013 17:50:57 -0600, Daryl
wrote: On 3/22/2013 4:16 PM, wrote: On Fri, 22 Mar 2013 15:16:58 -0600, Daryl wrote: On 3/22/2013 2:59 PM, Jim Wilkins wrote: wrote in message ... VERY common problem on "A Piece of Crap" UPS systems (as well as some cheaper ones) but when they split they don't leak. The acid in an AGM battery is Absorbed in the Glass Mat. jsw No, the Glass Matt just keeps it from sloshing around. You break open that case and the solution will leak out post haste. And you have NEVER seen an accidental leaking of an AGM battery. Now just admit it. Those that can: Do. Those that can't: Teach Daryl They are also called "starved electrolyte" batteries - and even when fractured they do not "leak". They are very similar in that respect to the older "gell cell" Totally different internal makeup between the two. Like many, you are confusing the two and thinking the internal makeup is similar. They aren't. I'm not confusing them. I know the difference - and I have some experience with both gel and AGM batteries in UPS units over a 20 year history, as well as flooded cell deep discharge batteries in EV use - going back that far as well, plus "gel" experience in wheelchair batteries and the old "cyclons" I have yet to see fluid leak from an AGM battery but I'll admit I've never smashed a good fresh one. Smashed a few dead ones - and they are just "damp" "starved electrolyte" batteries have a fiberglass mat of almost felt consistency which is wet with acid to about 95% capacity - so if the case is broken there is NO free electrolyte to leak out. This is why they are not considered hazardous and do not require hazardous labeling, and can be shipped by air. The AGM must be kept upright since it does have free liquid in it. Baloney. A valve regulated recombinent gas absorbed electrolyte battery can be mounted, charged, and discharged in any position. What you see when it's case is bulged is from the Hydrogen and Oxygen being unable to be vented due to excessive overcharging or the vent hole is plugged up. Like the old style Lead Acid, when it vents, it burns off the H2O breaking it up to Hydrogen and Oxygen Gasses. When you open one up that has done this, what is left is the other parts of the liquid in the form of solids or actually, powder. The Plates are still lead. Wrong. In an AGM (recombinent gas absorbed electrolyte) battery the oxygen and hydrogen are catalytically recombined and never vented under normal conditions. In extreme overcharge, water vapout pressure can bulge the case if the valves don't vent and the battery boils dry - which can also bulge the case. You might use a lot of the batteries, but you don't understand them very well. This one, like the unsealed lead acids can form Sulphates on the plates which shorten the life of the battery because of running them below 50%. The good news is the desulphators work offered with low amperage may recover them to almost new condition when that happens. And AGM batteries are virtually imune to sulphation When you need a battery that cannot be kept in an upright position, you choose the Gel Cel. In this battery, the Sulfuric Acid is mixed with Silica Fume and it makes it into a gel. The Plates are of a Calcium makeup and are not lead. Again, Baloney. They are calcium doped lead. The calcium is used in gell and flooded acid batteries to harden the lead and strengthen the plate without the excessive gassing and corrosion, and self discharge of the 3% antimony alloy of a "conventional" battery. Some batteries use a "conventional" positive and a calcium negative grid - with the lead paste and lead sulphate paste caked to the grid, and some use calcium alloy grids for both (more expensive). A calcium/calcium battery does not gas much and is used in sealed recombinent (maintenance free) batteries. With AGM the plates are supported by the glass mat, and in many cases no calcium or antimony is required. Pure lead thin film AGM batteries are state of the art for telecom and medical equipment use. They give the highest power density per unit volume of any lead based battery technology. They will beat any gel battery hands down - but they do not come cheap. They can put out insane current, and can be fast charged without damage. Odyssey batteries are thin plate pure lead AGM batteries. We use them in recreation aircraft use almost exclusively. People confuse the AGM with the Gel Cel all the time. If you want the best, longest lasting UPS battery, get rid of the AGM and go with the Gel Cel. They cost more but last much longer. An AGM battery can stand much higher charge and discharge than the rather fragile and fussy Gel Cell, which is why gell cells are virtually extinct in small to medium UPS units and MOST other applications. Gell and flooded acid batteries both require about 115% of their rated output in charge - ie - a 100 ah battery requires 115ah of charge (when new - they can get as bad as 125% and still function). AGM batteries are down around 102%. This means a LOT less heat in AGM applications compared to gel. (all that extra wasted 13% power is shed as heat) For long slow discharge, in a device with the proper charge controller for Gel use, the Gel is still a (reasonably) good solution. For heavy loads, not so good. For high charge rates, not so good. For mobile high vibration use, not so good - and they DO require a specially programmed charger. Do NOT charge gel batteries with a normal flooded acid or agm charger. A pure lead AGM battery is almost always a better choice. |
#225
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Is the 787 a failure ?
wrote in message
... For long slow discharge, in a device with the proper charge controller for Gel use, the Gel is still a (reasonably) good solution. For heavy loads, not so good. For high charge rates, not so good. For mobile high vibration use, not so good - and they DO require a specially programmed charger. Do NOT charge gel batteries with a normal flooded acid or agm charger. A pure lead AGM battery is almost always a better choice. Good advice. While searching for a comparison of flooded, AGM and gel float voltages I found this: http://www.windsun.com/Batteries/Battery_FAQ.htm I charge all types except NiCd and NiMH with a lab supply, and use it to temporarily recover old NiCd tool packs that have dropped to zero and won't charge on an automatic charger, and to reform old electrolytics. Lead-acids reveal their state of charge by the increasing voltage needed to force a constant current into them. I get the endpoint topping or float voltage from the maker's data sheet, or for flooded cells by measuring the specific gravity and watching for bubbles in all cells. I've noticed that the fully charged and endpoint voltages are about 0.2V different for two identical SLA31 batteries bought a year apart. The cause could be manufacturing differences in the plates, or variations in the volume or concentration of the acid. jsw |
#226
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Is the 787 a failure ?
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#227
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Is the 787 a failure ?
"Michael A. Terrell" wrote in message
... wrote: VERY common problem on "A Piece of Crap" UPS systems (as well as some cheaper ones) but when they split they don't leak. Their battery float voltage can be adjusted, if you don't mind fussing with them and know what to set it to. http://www.jjoseph.org/notes/apc_sma..._float_voltage they are designed to recharge quickly so they are ready for the next minor outage. That way they can use a smaller battery and sell them at a price that most users can afford. I have small, cheap Conext and Newpoint UPSs that take half a day to recharge after a run time test. IIRC they draw about 25W from the AC line when fully discharged. jsw |
#228
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Is the 787 a failure ?
On Sun, 24 Mar 2013 03:04:41 -0400, "Michael A. Terrell"
wrote: wrote: VERY common problem on "A Piece of Crap" UPS systems (as well as some cheaper ones) but when they split they don't leak. they are designed to recharge quickly so they are ready for the next minor outage. That way they can use a smaller battery and sell them at a price that most users can afford. Yes, but MANY other brands that sell to the same market - at the same or similar price point, have less of a problem. |
#229
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Is the 787 a failure ?
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#230
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Is the 787 a failure ?
Jim Wilkins wrote: "Michael A. Terrell" wrote in message ... wrote: VERY common problem on "A Piece of Crap" UPS systems (as well as some cheaper ones) but when they split they don't leak. Their battery float voltage can be adjusted, if you don't mind fussing with them and know what to set it to. http://www.jjoseph.org/notes/apc_sma..._float_voltage I get five year life out of the steel cased APC UPS without modifications, and I have only bought one new. that was 14 years ago. Since then I have accumulated dozens of free units that work when you replace the battery. I have small, cheap Conext and Newpoint UPSs that take half a day to recharge after a run time test. IIRC they draw about 25W from the AC line when fully discharged. -- Politicians should only get paid if the budget is balanced, and there is enough left over to pay them. Sometimes Friday is just the fifth Monday of the week. |
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