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Old Nov 05, 2010, 06:25 PM
like a rock!
gravityKills's Avatar
Finland
Joined Oct 2007
2,473 Posts
just guessing... it could be the two healthy cells causing a reverse voltage of 4.7 V over the broken cell.
Call the voodoo doctor.
Or the fire brigade.
Heck, Ghostbusters

References for the above claims would be highly appreciated.
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Old Nov 06, 2010, 03:38 AM
Boffin
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Victoria, BC, Canada
Joined Apr 2001
3,400 Posts
The plating work I referred to was back in the '70's through early '90's and I don't think any of it is online, though I have a vague recollection that Buchmann referred to it on his website. NASA was looking at Li use in satellites and Moli had a lot of internal work.
My point about the F was that the smoke can kill you whether or not is contaminated with a small quantity of toxin.

Rick.
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Old Nov 06, 2010, 08:43 AM
Space Coast USA
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Space Coast
Joined Oct 2000
21,164 Posts
Sometimes the message gets lost in the details.

IMO, the bottom line.
1. There is no Lithium metal in Lithium-ion-polymer batteries under normal use.
2. The smoke released during burning is more toxic than normal wood burning smoke.
3. Water, sand and some other materials are recommended in most MSDS's for fighting a lithium polymer battery fires. (See the MSDS's for details - post #905)
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Old Nov 07, 2010, 01:57 AM
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USA, MD, Frederick
Joined Jan 2010
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What makes me wary about using water:

*Possible formation of hydrogen fluoride (HF) and phosphorous oxides during fire. LiPF 6 salt contained in the electrolyte releases hydrogen fluoride (HF) in contact with water. Upon contact with moisture, including tissue, hydrogen fluoride immediately converts to hydrofluoric acid, which is highly corrosive and toxic, and requires immediate medical attention. Poisoning can occur readily through exposure of skin or eyes, or when inhaled or swallowed. Symptoms of exposure to hydrofluoric acid may not be immediately evident. HF interferes with nerve function, meaning that burns may not initially be painful. Accidental exposures can go unnoticed, delaying treatment and increasing the extent and seriousness of the injury.
*During water application, caution is advised as burning pieces of flammable particles may be ejected from the fire.

So water may be fine if you're outside, but in an enclosed area like a garage, maybe not so.
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Old Nov 13, 2010, 02:16 AM
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United States, UT, Salina
Joined Apr 2003
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The percentages are so tiny, less than getting aids from unprotected sexual contact.

Yet such great hype about them.
Can you factor in the real odds?
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Old Nov 13, 2010, 08:52 AM
Space Coast USA
hoppy's Avatar
Space Coast
Joined Oct 2000
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Quote:
Originally Posted by Bilbobaker View Post
The percentages are so tiny, less than getting aids from unprotected sexual contact.

Yet such great hype about them.
Can you factor in the real odds?
What are the percentages?
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Old Nov 13, 2010, 11:54 AM
like a rock!
gravityKills's Avatar
Finland
Joined Oct 2007
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On this site you'll find a couple of hundreds of reports about burned models, workshops, cars and houses. But I agree, they are statistically insignificant
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Old Nov 13, 2010, 12:23 PM
characters welcome!
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United States, CA, Bear Valley Springs
Joined Feb 2000
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Quote:
Originally Posted by gravityKills View Post
On this site you'll find a couple of hundreds of reports about burned models, workshops, cars and houses. But I agree, they are statistically insignificant
That's just this site and those that were reported. You don't think there's one or two more that we don''t know about?

I just don't get it. We have insurance when we drive (mostly) and for our homes in case of fire or other damage but some don't give a rip when it comes to insuring oneself from a known hazard by simply using an inexpensive, proper containment proven to manage the risk.

mw
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Old Nov 13, 2010, 01:52 PM
Things that do fly
Magic k2's Avatar
In my house ;-) The uk
Joined Dec 2008
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Quote:
Originally Posted by Mark Wood View Post
That's just this site and those that were reported. You don't think there's one or two more that we don''t know about?

I just don't get it. We have insurance when we drive (mostly) and for our homes in case of fire or other damage but some don't give a rip when it comes to insuring oneself from a known hazard by simply using an inexpensive, proper containment proven to manage the risk.

mw
Yep i would love to know how many lipos have gone pop fizzz,lots of people on rc groups that dont even know of this thread and lots more on other web groups also.
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Old Nov 13, 2010, 08:48 PM
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USA, KY, Florence
Joined Aug 2007
3,078 Posts
FYI:- don't try this at home.

I charged up 3 2200-3s packs that were getting weak and hung them in a tree.

I shot them with a .22.

A little smoke, some strange looking gas came out but no fire. I had my 85 year old mom video taping in case it was spectacular, but it was a dud. The video tape is not worthy of uploading.

On another note: Try to avoid hooking them up in parallell.
In the ESmart-600 some guys were taking 4 2200 3 s packs and hooking them in 2 series, 2 parallel. One of the packs was not charged, and all 4 packs caught on fire in the air, resulting in a spectacular crash.
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Old Nov 13, 2010, 10:23 PM
Got Another Prop?
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United States, VA, Hampton
Joined Aug 2006
590 Posts
I witnessed yet another LiPo fire recently at the “Electrics over Tidewater” event. A pilot was demonstrating a helicopter with a borrowed helicopter while the crowd kept shouting, lower, Lower LOWER!!!

The crowd’s wish was granted and the helicopter did that all too familiar chicken dance.

The battery was immediately, unplugged, removed and inspected with no apparent damage. Minutes later someone noticed the pack was beginning to swell and the LiPo was placed onto a large gravel clearing. Many watch as the cell continued to swell, smoke, catch fire and slowly caused the neighboring cell to react to the heat. This pack developed into a rather lengthy chain reaction that progressed with each cell independently puffing, smoking and then burning. The entire process lasted in excess of 30-minutes and this was NOT your typical “Smoke-Poof” LiPo fire.

The EOT event director captured the below photos shortly after the pack was tossed onto the gravel.

My respect and awareness of LiPo Fires has leaped to a higher level.
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Old Nov 13, 2010, 11:35 PM
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USA, KY, Florence
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The gas that comes out is wierd and toxic. Try not to breath it.
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Old Nov 14, 2010, 12:03 AM
The "Foaminator"
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United States, CA, Los Angeles
Joined Mar 2007
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Quote:
Originally Posted by WadesRC View Post
I witnessed yet another LiPo fire recently at the “Electrics over Tidewater” event. A pilot was demonstrating a helicopter with a borrowed helicopter while the crowd kept shouting, lower, Lower LOWER!!!

The crowd’s wish was granted and the helicopter did that all too familiar chicken dance.

The battery was immediately, unplugged, removed and inspected with no apparent damage. Minutes later someone noticed the pack was beginning to swell and the LiPo was placed onto a large gravel clearing. Many watch as the cell continued to swell, smoke, catch fire and slowly caused the neighboring cell to react to the heat. This pack developed into a rather lengthy chain reaction that progressed with each cell independently puffing, smoking and then burning. The entire process lasted in excess of 30-minutes and this was NOT your typical “Smoke-Poof” LiPo fire.

The EOT event director captured the below photos shortly after the pack was toss onto the gravel.

My respect and awareness of LiPo Fires has leaped to a higher level.
Which goes to show no matter how little the cash, keep an eye on them for at least 30 minuets to an hour before assuming there OK!.
I have seen the same thing happen.
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Old Nov 14, 2010, 02:15 AM
like a rock!
gravityKills's Avatar
Finland
Joined Oct 2007
2,473 Posts
yea, the smoke is something I really don't want inside my apartment / car / lungs. It clings to clothes etc, you can still smell it after days.

one of the chaps at our field has a blowpipe with metal darts that easily punch through the whole pack. That has become the favourite method of LiPo disposal, lately Just stay upwind.
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Old Nov 18, 2010, 07:43 PM
-_-
E-MO's Avatar
United States, CA, Oakland
Joined Sep 2005
828 Posts
I just received an order of three 7.4 5K 30C lipos fresh out of the package should I treat these as a loaded gun in my house or only after a charge has been put on them?
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