My good friend Ivan had a li po fire which devastated his workshop
huge loss of engines , batteries , turbines,airframes RC & CL
even 3 expensive transmitters
Fire dept put out the fire and now the mess is like a bomb site

warning to us all, dont leave a li po on charge un attended.

Question :  Will one of the li po bags on sale now protect from
fire, for example would it be safe on a timber self with the lipo
inside on fire ?

Vincent

Vincent,
How about some details on what he was charging, what charger, what mode they were charging in, etc?  Knowing what went wrong would be a big help to the rest of us.
Thanks.

My understanding is that these things just blow sometimes, although errors in charging certainly increase the possibility for problems.

At home I charge mine under a big heavy flower pot, on a concrete floor, in a room next to my office.  So hopefully if it blows it won't immediately take down the shop, and I'll be there to do something about it.

Hi Tim,

Looks like you have a very safe charging environment. In the rare case that something goes wrong you will still be safe, stink from black smoke, but safe! If everyone followed your lead we would not have even the rare event that started this thread. :-)

Your statement "these things just blow sometimes" is a common misunderstanding. There are millions of these batteries in use throughout our little spaceship, without mishap when used/stored/transported properly. Like you eluded to, errors in charging are by far the most common cause of problems in our modeling use of LiPos. Overheating them is another problem as well as "any" opening of the thin protective casing (dents, cuts, etc.). Shorts are another problem. Continued use of a "puffed" battery is another problem. Poor packaging during storage and handling is another problem, etc.  But they do NOT just blow all by themselves, they need help, ...... usually from us humans. ;-)

Like Crist said, it is important to find out the facts. These will be a big help to all of us in our efforts to eliminate as many safety problems as possible. In FS the FAA has been very good at communicating details of all accidents to all CFI's so that we can train people to avoid the problems that cause these accidents. We should try to do the same in our area of aviation. :-)

 

Well said Tim. I agree with you 100%, even after taking all other precautions it is still worth the extra step of enclosing the batteries while charging.

RE: the dangers of wet systems, true how true. For the most part I think most wet modelers are very careful with their Alcohol or gas fluids. But like you said, they are playing with very powerful bombs. Accidents are very rare but they do happen. I still fly with gas in my IMAC planes (slowly converting them to E power ;-) and I have seen only one fire and also one jet crash and burn to ashes from burning JP-4.

I also have a very good friend that had his shop severely damaged by an explosion of the fumes from his glow fuel can. There was not a big fire, it seems that the explosion used up a lot of the available O2 in a pretty well sealed shop and there was not a lot left over for a big fire? That was their theory. My friend was not home at the time, his neighbor called the fire dept. The fire dept. along with the insurance investigator said that it appeared that his cat had knocked a large screw driver off his bench, the screwdriver arced across the 12V starter battery in his flight box, and this ignited the fumes from his not so perfectly sealed fuel can causing an explosion. Unfortunately, the cat was severally punished for it's misstep and did not survive the explosion/fire. ...... I have heard of several fires started by exposed 12V starter flight box batteries being arced causing a spark. I think cats being involved is still very rare. ;-)

So we are not alone in our potential dangers. And we haven't even started talking about fingers/hands in the prop problems with wet systems. I have three friends with serious injuries. One missing 1/2 of two fingers, one with disabling lacerations of the hand, and one with several large lacerations of the forearm. At one I was there to see all the blood and parts of flesh scattered about the pits.

At the NW CL contest this year there were three hand injuries that required medical attention. I am sure there are many more each year with wet system "systemic" safety problems.  So when the ECL critics point to our rare ECL safety issues, I am reminded of "those who live in glass houses ........." ;-)

Regards, 

 

Hi Dennis A.,

Thanks for the youtube. This is the same one that is shown on the LipoSack web site. Your right, it is compelling.

Their web site has a lot of info:          http://www.liposack.com/products.htm

I called the company many years ago and asked if they were using the Nomex fire safety material used by race car drivers. They said no, it was not good enough, it melted. They use an expensive aerospace material that can stand up to the high heat flames. This product is made here in the USA, using materials made in the USA. I do not trust the cheap imitations, I have been told that they burn through easily. IMHO the extra few $$ are well worth it for a safe, reliable product made here in the USA.

As I said before, I hope everyone gets the new LARGE version. It is really made for our ECL CLPA size batteries. It has the room inside to spread out the flames and debris without burning through. The smaller version is marginal for our size batteries.

I like their storage/transport bags too. They now have a link on their web site to a mfg. who makes a cool LiPoRack for charging.

After thousands of uneventful LiPo charges it is tempting to get complaisant at times. But then I think of the very small amount of effort and expense it takes to avert a potential disaster and I use my LiPoSack or one of my ceramic containers on EVERY charge. :-) .... something about "better safe than sorry". ;-)

Thanks again for the youtube link. I hope everyone watches it. :-)

Not quite prevention, but in the event of a fire what is the best extinguisher to use?

My guess is powder (as opposed to CO2, foam or water), but I'm no expert.

Excellent question.

I have a general purpose fire extinguisher on my tile covered charging table. You want the one that lists for: electrical, wood, etc.

The LiPos we use are really hybrid batteries, a combination of Lithium Polymer and Lithium Ion. This means that it is very difficult to put out the initial chemical fire because it brings it's own O2 to the event and is burning at around 1,400 degrees f. Fortunately this fire only lasts a very short time (in our ECL case usually 4 short fires in succession) because is burns up its own flammable material quickly and is done.

The fire extinguisher is there to insure that the fire does NOT spread to any surrounding materials, and if it does, to make sure they are extinguished ASAP.

Another item while your at home depot buying your extinguisher is to get an inexpensive portable "smoke detector" to place above your charging area.

Again, please keep in mind that this is an extremely rare event. Me, and my electric flying friends have 10s of thousands of charges between us without damaging anything. But the good news is that even this very rare event can be prevented with some simple and inexpensive measures. :-)

Thanks for your great question.

I think cats being involved is still very rare. ;-)

You can't trust cats, Rudy.  Here is Spencer plotting no good with the Bomber starting battery.