wheels 543 Posted February 9, 2017 Share Posted February 9, 2017 Doesn't give a whole lot of confidence of improvements of the design now does it. 1 Quote Link to post Share on other sites
Dtwo 157 Posted February 9, 2017 Share Posted February 9, 2017 Hmmm, seems more of a comment about correct waste disposal than battery design. I don't have any personal knowledge about the relevant standards of their waste disposal regime but I would suspect.... rather sh*t? Quote Link to post Share on other sites
erice 732 Posted February 9, 2017 Share Posted February 9, 2017 all here for those really interested https://www.youtube.com/watch?v=a5W19Spmw8Q https://www.cnet.com/news/samsung-galaxy-note-7-return-exchange-faq/ but basically some samsung galaxy note 7 owners had their lithium batteries go into thermal runaway + burn in a cloud of toxic smoke samsung first blamed a bad batch of batteries tried to recall + replaced them but then other batches started burning so new batteries were produced but some of them also randomly burned in people's pockets and bag, so now the design has been blamed all G7 phones have a worldwide recall and owners are sent a fire-proof bag to put into a fireproof box to be put into a normal box and returned to samsung i'm guessing this recent factory fire is where these boxes were unpacked and the phones stacked up for disassembly and recycling and while waiting for that 1 of the batteries burned and set off the others just showing how misunderstood lithium batteries are and this isn't limited to samsung and phone batteries iphone battery - "don't pry the battery but pull the plastic tab on the battery" https://youtu.be/JFt3WoPyloU?t=34 new tesla lithium car batteries are still burning and even virtually cost-no-object 787 dreamliner batteries have done their best to torch the plane it may only be a small percentage but until they know what's happening rather than making educated guesses lithium house batteries won't be going into my boat Quote Link to post Share on other sites
Battleship 100 Posted February 9, 2017 Share Posted February 9, 2017 The batteries sold for house banks use different technology to the lithium batteries that Tesla and cell phone manufacturers use. Lifepo4 is a lot safer than lithium ion and a lot more forgiving to abuse. http://www.epectec.com/batteries/lithium-battery-technologies.html I know of a boat that had it's lead acid batteries catch fire after running them too dry so they are not immune either. Quote Link to post Share on other sites
Beccara 25 Posted February 10, 2017 Share Posted February 10, 2017 Lifepo4 don't flame during puncture just smoke and it's quite a low thermal reaction too. There's too many different chemistries to just look at a "Lithium Fire" Quote Link to post Share on other sites
Beccara 25 Posted February 10, 2017 Share Posted February 10, 2017 Oh and even with the exploded lithium chem's you can still protect/contain - Just like you should vent a FLA battery you should also ensure any large energy source be it battery or fuel Quote Link to post Share on other sites
wheels 543 Posted February 11, 2017 Share Posted February 11, 2017 The LiPo's used by the likes of Solar Companies are a completely different Beast to that kind of Li batteries used to Cell Phones KM. Not that there hasn't been problems in the earlier days, but it is uncommon for the newer ones to cause a problem. Quote Link to post Share on other sites
Beccara 25 Posted February 13, 2017 Share Posted February 13, 2017 Well the first video I posted was a LifePo4 which is what most boat/marine/RV packs will be of, Either DIY or purpose built like Victron but they just smoke out, Internal heat gets up near 200c but external there is no fire or ignition. Dead shorts are the same as well. In my experience the biggest danger from a bank of LiFePo4's being punctured or dead short is the gas expansion. These banks are often in tight spaces and little thought is given to where the gas from the PRV will go so you can/do see panels blown out/doors blasted off their hinges FLA's do much the same but rather than smoke spray acid out and create hydrogen gas, Not as fun to watch but really batteries are box's of angry pixies wanting to escape - They are all dangerous in accidents Quote Link to post Share on other sites
too_tall 15 Posted February 13, 2017 Author Share Posted February 13, 2017 The reality is that batteries contain a lot of energy, and when that becomes uncontrolled, it ends poorly. Quote Link to post Share on other sites
Black Panther 1,568 Posted February 13, 2017 Share Posted February 13, 2017 WTF are you on about? Rottflmao. Quote Link to post Share on other sites
wheels 543 Posted February 14, 2017 Share Posted February 14, 2017 I've just redone aviation law and 95% of the words used in that are acronyms so I'm quite surprised Great, please translate whatever the heck it is my Wife speaks please. Most of the time I just stare blankly and wonder why the heck I bother asking how her day was Re the Batteries, i am trying to think of why anyone would be Puncturing, at least unintentionally, a bank of LiPo's. Quote Link to post Share on other sites
erice 732 Posted February 14, 2017 Share Posted February 14, 2017 spear-gun goes off hey it happens just ask the fish about the waters around marine reserves Quote Link to post Share on other sites
Beccara 25 Posted February 14, 2017 Share Posted February 14, 2017 Ok so seems I've kicked a nest here, My bad. Who here knows about the Samsung Note 7 fires? For those of you that don't it was a new cellphone that got released Aug 2015 and started to catch on fire while charging, It took a long while to figure out but in the end it was battery defect in manafacturing Here we can clearly see what the issue is, A mechanical issue lead to an electrical one and in the case of cellphone batteries you have a problem known as thermal run away where the hotspot around an internal/external fault which cause a chemical reaction in the surrounding area producing heat which in turn creates a chemical reaction in an even bigger area etc etc - This almost always ends up in a fire outside the battery It's worth noting at this point aswell that pretty much all failure modes of Lithium batteries are "Dead Shorts", The above Samsung Note 7 problem is a dead short, a puncture through the battery is a dead short in that the puncture breaks down the barrier between the cathode and anode allowing for high current, Because this breakdown isn't clean it's high resistance and resistance generates heat: The puncture causes a "dead short" the dead short creates heat internally and burn's off the material around it. In a consumer lithium polymer battery this causes a fire because of thermal runaway, In lifepo4 this causes smoke/gas generation but no fire. As for why you would puncture your battery? You wouldn't but mechanical damage/defects create the same outcome - External damage from denting it/deforming the exterior case can create the same issue as hitting it with a nailgun, You break down the barrier between the "plates" and out come the angry pixies Here's a really good video showing an external dead short on a lifepo4 battery pack: It shows off nicely the PRV or pressure relief valve - The gas shooting up from the top comes from an engineered weak link that's meant to fail first, Then the battery case fails entirely due to the expansion of the battery material. At the end they just dead short a single cell and end up melting a bolt and not much else This video also shows a drop in 12v battery replacement with lithium pack + BMS As too_tall said, Any battery is dangerious - it's storing a large amount of energy, Lead Acid feels safe because we're used to it Congrats KN on passing Av Law, Are/Have you going to redo CPL Met? Is it still a prick of a test? Quote Link to post Share on other sites
Beccara 25 Posted February 15, 2017 Share Posted February 15, 2017 Nice, CPL is worth it if you can get past the BS chaff crap in the exams, Human factors is awesome in CPL but crap in PPL, Flight is kinda meh in both but i've heard many, many times CPL Met is the hardest in the world Quote Link to post Share on other sites
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