US69 Posted October 7, 2016 Share Posted October 7, 2016 1 hour ago, Rehab1 said: i better think about once more if i will Change my V3 to Li-Po's... Link to comment Share on other sites More sharing options...
xebeche Posted October 7, 2016 Share Posted October 7, 2016 29 minutes ago, KingSong69 said: i better think about once more if i will Change my V3 to Li-Po's... Maybe if you intend to use it as some kind of rocket boost for a brief moment Link to comment Share on other sites More sharing options...
Keith Posted October 7, 2016 Share Posted October 7, 2016 I'm very anti LiPo sacks, I think they give a totally false sense of security. As you will be aware, model aircraft crash, sometimes at 3 figure speeds and many are powered by very fragile soft cased LiPo's. One very important rule of thumb is: If you crash, do not put the LiPo into your car until you have monitored it for at least 30 minutes. Last year (I wish I could find the article) one modeller, placed is well concertinered LiPo into a LiPo sack and then put the wreckage into his car - he lost the car. I've also seen people put LiPo's into LiPo sacks and charge them in their car. By definition, because they are (or were) flying they are in a bloody great big field, how difficult is it to charge a pack, or leave a damaged pack out in the open air? IMHO, LiPo sacks cannot completely contain what can be a serious amount of heat and flame and I'm seeing way too many people substituting a LiPo sack for common sense. Personally I use army ammo boxes, insulated inside and with a number of small 1/16th inch holes drill into the lids under the handles (to stop rain getting in) so they don't become a pressure cooker bomb if one or more does go up. I would still never put a damaged pack in or charge a pack inside the box. Link to comment Share on other sites More sharing options...
Rehab1 Posted October 7, 2016 Share Posted October 7, 2016 32 minutes ago, Keith said: Personally I use army ammo boxes, insulated inside and with a number of small 1/16th inch holes drill into the lids under the handles (to stop rain getting in) so they don't become a pressure cooker bomb if one or more does go up. I would still never put a damaged pack in or charge a pack inside the box. Excellent idea! How did you gauge how many 1/16" holes to drill to allow the gases to escape? Link to comment Share on other sites More sharing options...
Keith Posted October 7, 2016 Share Posted October 7, 2016 29 minutes ago, Rehab1 said: Excellent idea! How did you gauge how many 1/16" holes to drill to allow the gases to escape? I would love to say that I applied Boyles Law, but since I'd have absolutely no idea what temperature the inside would reach, let alone exactly how much gas would be produced I actually stuck a wet finger in the air and drilled 4 holes on the basis that ammo boxes are damn tough cookies anyway with very well clamped lids so as long as there is some pressure relief it ought to be enough. I think a bigger concern, if there were no holes, would probably be unwittingly opening one some time after a cell had gone off and getting the lid in your face. By the way, I've never actually been able, in more than 10 years use, personally to get a LiPo to ignite. If I get one where a cell, usually only one, has puffed up and gone high resistance I usually make the pack safe to dispose of it by banging a 6" nail through it (outdoors of course) and then, when it stops fizzing and venting steam I drop it in salt water for a day. It is then completely inert. I could,and should, simply drop it in the salt water so it discharges, without using the nail at all, but where's the fun in that :-) Link to comment Share on other sites More sharing options...
Rehab1 Posted October 7, 2016 Share Posted October 7, 2016 2 hours ago, Keith said: If I get one where a cell, usually only one, has puffed up and gone high resistance I usually make the pack safe to dispose of it by banging a 6" nail through it (outdoors of course) and then, when it stops fizzing and venting steam I drop it in salt water for a day. It is then completely inert. Do you perform 'Keith's LiPo Disposal' process on a tree stump? What about drilling another hole on the lid of your ammo box (you plug it with bubble gum afterwards) and then drive the nail directly through the lid into the battery? I get rid of 4 and 8 foot fluorescent tubes using a similar method where I slide the fluorescent tubes into a PVC pipe with pre-drilled vent holes. I then cap the ends and drive a nail through the pvc pipe into the glass tube. KaBoom... I then just take off an end cap and empty the contents into a bag or box. Yah...I know...Al Gore would smack me Link to comment Share on other sites More sharing options...
US69 Posted October 8, 2016 Share Posted October 8, 2016 i just accidently found the reason, why the FAA has forbidden Lithium batteries on passenger flights and why this is not just a "stupid regulation": http://avherald.com/h?article=4307772e/0006&opt=0 Other articles also state that this crash is the main reason for safty regulations on lithium ionen batteries... Link to comment Share on other sites More sharing options...
RobertLong Posted October 9, 2016 Share Posted October 9, 2016 On 2015/12/12 at 3:27 AM, MarkoMarjamaa said: It would be right time respectful chinese manufacturers create some kind of certificate for safe batteries. Real certificate, not a copied one. If they want to keep their markets. Seems this a problem mostly with hoverboards and the reason might be, people buy the cheapest hoverboards not thinking about quality. Agree,every sellers and Manufacturer should keep every product sale and good quality,in order to get long-term business relationship,that's really important. We have enough products in stock in Germany and Italy warehouse to satisfy all our Europe customers. www.gooodhoverboard.com Robert: ranpasales@gmail.com Link to comment Share on other sites More sharing options...
tjcooper Posted October 21, 2016 Share Posted October 21, 2016 @Keith I have been doing LiPo batteries for over 20 years now (I was at Sony when first LiPo were put in various consumer products). I have personally had two LiPo packs go off in my pocket. Luckily I felt the swell and heat and got them out of pocket before they went to flames.....which they did do and a photographer at our flying field caught on film (yes, the old mylar and silver stuff). Anyway, look on rc-groups and search for keywords LiPo and "vent and flame". Hundreds of posts. What you are looking for is the video on early user who made a 50mm Army Ammo can carrier. He cut a 3 inch hole in unit and put Stainless Steel flex pipe to vent the smoke and flames outside of his station wagon. So before he put system into operation, he decided to test out blowing up a single 3S 2200 maH pack (very expensive in those days). When the pack went to "vent and flames" there was enough force to blow the lid off the locked ammo can. That convinced him there is no safe way to sustain a fire. The video he captured is very convincing. With the new planes that need 6S at 12000 maH, that would burn the car to the ground in a matter of seconds. So don't think a metal ammo can will do much. What is needed is an open vessel that is covered on 5 sides. The open side directs the flame and smoke to an open environment. That is why I charge all my batteries in a chafing dish in the garage. I have had two packs go up on me. The dish stops the fire from spreading and the heat from melting everything around it. But the ash and cinders will cover over the whole garage. Serious cleanup job. I have videos I made in the early days of a LiPo in a fish tank full of water. The LiPo goes to flames and the plastic sack melts. The LiPo produces its own O2 and so the burning continues even under water. New LiPo batteries are much safer than the old ones. But everyone should treat them as a hand grenade with the pin barely in the hole. tjcooper Link to comment Share on other sites More sharing options...
tjcooper Posted October 21, 2016 Share Posted October 21, 2016 d@KingSong69 If you look at the FAA and IATA final reports on the Dabai UPS crash, they put the final blame on "pilot error". they had almost 15 minutes since fire was detected until they crashed. The biggest problem was that they could not find the spare O2 supply and the First Officer had set his mask wrong that let in smoke so he could not breath. All that said, the start of the fire was never properly determined because the vessel was burnt to crisp. That is why all the LiPo batteries, which were not in the areas where the fire started, were burned and opened. They were incinerated after the crash. There is evidence that some LiPo batteries were "smuggled" into the region where fire started. there is also evidence that fertilizer and other flammable items were located in the region where the fire first started. So bottom line, we do not have "smoking gun" proof that LiPo started the fire. And that is in the final report. But the danger of LiPo is real and it COULD HAVE BEEN the source. China has 4 main factories that make over a BILLION LiPo batteries a year. There only reported fires for LiPo's going up have come from accidents where fork lift tractors have collided and broken packs. So "spontaneous" fires of LiPo are rather rare....but they do happen under stressful circumstances. So three things come out of this. Much better packaging is needed. Much better thermal detection in the cargo planes is needed. And specialized fire containment systems are needed. We have done this for year with the transport of liquid Hydrogen. They have some really good detection and prevention mechanisms. We need to do the same thing for LiPo. But we should not say "they are totally dangerous and we can never use them again". tjcooper Link to comment Share on other sites More sharing options...
US69 Posted October 21, 2016 Share Posted October 21, 2016 1 minute ago, tjcooper said: d@KingSong69 If you look at the FAA and IATA final reports on the Dabai UPS crash, they put the final blame on "pilot error". they had almost 15 minutes since fire was detected until they crashed. The biggest problem was that they could not find the spare O2 supply and the First Officer had set his mask wrong that let in smoke so he could not breath. All that said, the start of the fire was never properly determined because the vessel was burnt to crisp. That is why all the LiPo batteries, which were not in the areas where the fire started, were burned and opened. They were incinerated after the crash. There is evidence that some LiPo batteries were "smuggled" into the region where fire started. there is also evidence that fertilizer and other flammable items were located in the region where the fire first started. So bottom line, we do not have "smoking gun" proof that LiPo started the fire. And that is in the final report. But the danger of LiPo is real and it COULD HAVE BEEN the source. China has 4 main factories that make over a BILLION LiPo batteries a year. There only reported fires for LiPo's going up have come from accidents where fork lift tractors have collided and broken packs. So "spontaneous" fires of LiPo are rather rare....but they do happen under stressful circumstances. So three things come out of this. Much better packaging is needed. Much better thermal detection in the cargo planes is needed. And specialized fire containment systems are needed. We have done this for year with the transport of liquid Hydrogen. They have some really good detection and prevention mechanisms. We need to do the same thing for LiPo. But we should not say "they are totally dangerous and we can never use them again". tjcooper ...i never said that we should not use them? The arguing was more if it is just a "stupid buroecratic regulation"...or a regulation that makes sense! And where the regulations because of Lithium Ionen batterie come frome, because of that accident there were installed... Even if in that case it is not a hundred procent clear what started the fire... There also have been the worldwide shutdown of the Boing dreamliner...after 3 or 4 problems/smoke/fire with its Lithium Ionen batterie. so i think its just proved to say, that there is a reason for li Ion regulation. Link to comment Share on other sites More sharing options...
MarkoMarjamaa Posted October 25, 2016 Share Posted October 25, 2016 "clever" way to circumvent regulations. Link to comment Share on other sites More sharing options...
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