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Old Oct 14, 2003, 02:32 PM
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Baltimore Bwi Rr Stn, Maryland, United States
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RE: Ultimate Guide to Lithium Polymer Batteries

Now that the "Ultimate Guide to Lithium Polymer Batteries" has us scared to death (can we spell paranoia?) let us immediately puncture our Lithiums and throw them in salt water. If we don't do this we are going to die!!! Please don't misunderstand me! Lithiums are different from NiCDs and NIMH batteries and the misstreatment of Lithiums can be most devistating. If the temperature of a Lithium exceeds a certain point, a chemical reaction starts that can't be stopped. This leads to the possibility of fire. If Lithiums arn't abused and kept below this critical temperature they work just fine. The bottom line is don't abuse them and follow the manufactuer's instructions for charge and discharge.
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Old Oct 14, 2003, 03:05 PM
Just an average RC'er
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Laurel, Maryland USA
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I'll let someone else take this one... perhaps one of the people who had their car burned will chime in.

-Jim
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Old Oct 14, 2003, 03:16 PM
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Baltimore Bwi Rr Stn, Maryland, United States
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If Lithiums cause such devistation why aren't they outlawed? I just survived hurricane Isabel, are we going to have an ultimate guide to hurricanes? Bad stuff happens, much of it because people don't do what they are told (read and follow instructions). I stayed inside, as advised, during the hurricane and lived to tell about it.
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Old Oct 14, 2003, 03:17 PM
Random Flier
Oxford (UK) and Mtn View CA (USA)
Joined Nov 2002
1,409 Posts
Don't feed the troll...

Jim - thanks for your summary on Li battery usage recommendations. Can I suggest this also get added to the Ezone FAQ? This looks like it needs an update, and when I started this hobby found the FAQ to be very useful. Nowadays, of course, I fly almost exclusively Lithiums...
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Old Oct 14, 2003, 03:26 PM
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United States, FL, Casselberry
Joined Jul 2002
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There is a spectrum of attitudes toward these cells - from the paranoid to the cavalier.

I think the proper perspective is near the middle ground - more cautions that whanderson, and less paranoid than eliminating the cells.

Knowing that there can be serious problems when LiPoly cells are operated outside safe parameters is paramount, as is following appropriate precautions.

I use and am quite satisifed with my LiPoly batteries, but I understand that they can be hazardous under the right (wrong) conditions, so I make sure they are never charged unattended, always double check my settings and quarantine any pack that is subjected to crash loads before placing it in a vehicle or my home.

You milage may vary, but if you become complacent with these cells, experience has shown that can bite you.

Matt
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Old Oct 14, 2003, 04:31 PM
MKH
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Quote:
Originally posted by MattLarson29
There is a spectrum of attitudes toward these cells - from the paranoid to the cavalier. Matt
Absolutely correct, and the human factor will likely continue to cause most of the problems. I think the guide to lipolys is invaluable, but the skeptic in me knows that most lipoly users will not follow it closely. At least the information is out there, to be utilized, or ignored, as each user sees fit. Freedom is a wonderful, and dangerous thing.
Marcus
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Old Oct 14, 2003, 04:43 PM
DNA
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"The bottom line is don't abuse them and follow the manufactuer's instructions for charge and discharge."

There have been several reports of cells/packs that WERE being charged correctly and had not been abused, but still resulted in fires. Gary Wright's fire is a good example. There have been others as well. So your "bottom line" is meaningless.
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Old Oct 14, 2003, 07:22 PM
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In stating his opinion, I think whanderson covered all the bases, from pooh-poohing the tone of the Guide (paranoia) to issuing his own warning that LiPo failures can be devastating. That bottom line is especially interesting: If you never make a mistake by inadvertently abusing the cells, and if you always follow the manufacturer's instructions, you'll be fine. In other words, if you're perfect and never make mistakes, you won't have any problems with LiPos. Of course, that doesn't address the issue of a malfunction over which the user has no control, such as a glitching charger or unseen short in the cell.

The Guide represents a lot of input from a lot of people with a lot of lithium experience, as well as a lot of hard work from Jim McPherson. As such, I value it much more highly than the cursory opinion of any individual.
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Old Oct 15, 2003, 07:33 AM
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Baltimore Bwi Rr Stn, Maryland, United States
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It may appear my position on this subject is "cavalier." I assure you it is quite the opposite. Jim McPherson's guide is quite consistant with instructions provided by better LiPo manufacturers. It is the picture attached that causes me great concern. If lead acid, NiCds, or NIMH batteries are exposed to extreme laboratory conditions like the LiPo fire picture, they will also explode or catch fire. Where is the great concern on their care and feeding. I believe the intent of the message is honorable, but the way it is being presented causes unecessary fear. What is to prevent someone from taking this information and declaring LiPos a public hazard and having them outlawed? Don't scoff, look at what has been done to cigarettes.
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Old Oct 15, 2003, 08:19 AM
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Do you think it's better not to have a photo of what has happened to a fair number of LiPo packs when they have failed catastrophically? Then the optimists could imagine that LiPo catastrophic cell failure is nothing more than a puff of smoke, and pessimists could imagine a stick of dynamite detonating. The real truth lies somewhere in between, and is accurately depicted by the photo. Likewise, there'd be nothing wrong with showing photos of other types of cells failing as long as the photos accurately depict their typical failure modes.

As I said, I think you're trying to cover all the bases by repeating the guide's warning that lithium cells can be dangerous, but then using dramatic hyperbole that calls the whole Guide into question simply because you disagree with the inclusion of the photo.

Had you made a straightforward case in your first message for excluding the photo, this thread would have quickly focused on the issue you apparently intended to try to raise with all of the dramatic use of language about the Guide in general.
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Old Oct 15, 2003, 09:04 AM
St Charles Flyer
St Charles, IL
Joined Sep 2002
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It's clear, abuse LiPo packs and you eventually will have a very serious problem. It's not clear to me if you never abuse LiPo packs that you will NEVER have a very serious problem.

The photo of what happens to seriously abused LiPo cells demonstrated to me just how absolutely serious the results may be. It jumped my level of concern, and therefore my safe treatment of LiPo packs, a hunderd fold. I now know that I MUST be active in my safe use of LiPo packs.

I thank all the RCGroups contributors that brought this awareness to me and others.

STL
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Old Oct 15, 2003, 09:13 AM
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Whanderson ref your comment: "It is the picture attached that causes me great concern. If lead acid, NiCds, or NIMH batteries are exposed to extreme laboratory conditions like the LiPo fire picture, they will also explode or catch fire."

Extreme laboratory conditions? What is extreme about going off and leaving your charger do it's thing. Probably 99% of modelers put their batteries on charge and go off and leave them. I think your characterization of the experiment as "extreme laboratory conditions" is extreme. What was extreme about it? Do you think all the reported LiPo fires were the result of extreme laboratory conditions?

The bottom line is: These fires are happening with lipo cells. They are not happening with NiCd, NiMH or Pb acid cells. Sure there have been isolated incidents involving other cell chemistries but nothing like what is happening with the LiPcells. If that picture got your attention I say Bravo!, it did it's job.

hoppy
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Last edited by hoppy; Oct 15, 2003 at 09:29 AM.
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Old Oct 15, 2003, 10:07 AM
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Perth Westen Australia
Joined Jun 2003
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whanderson

"What is to prevent someone from taking this information and declaring LiPos a public hazard and having them outlawed? Don't scoff, look at what has been done to cigarettes."

Leaving aside the fact that cigarettes have killed or damaged the health of millions and we are yet to see a fatality from LiPoís, that cigarette manufacturers for decades covered up the adverse effects of cigarettes, there is of course nothing to prevent someone from taking this info and outlawing LiPoís generally.

Except the fact that they are used in a cell phones, and other consumer product and with protective circuits added are probably not much more of a hazard than PB, NiMh or NiCd. Also a fair amount of money is probably invested in production, money that would lobby against such a ban.

In most cases the producers of LiPoís for consumer products work on the basis that the principle of the Darwin Awards holds true. They try to make things foolproof (more to the point person proof). They will be able to show off their protection efforts and resist any such general ban.

But some fools who play with toy planes who buy cells with all the safety features and protections removed, who have no political clout, who burn their cars, houses and cause minor explosions etc are just the sort of targets that a politician or bureaucrat looking for a few political points in a bad election year would be happy to exploit by banning such dangerous practices or limiting the sale of product too that which incorporates protections which would effectively render the technology useless for our purposes.(1)

I am relatively new to electric flight and have gone from NiCd to NiMh to LiPoís in a short time, I would not willingly go backwards and I would rather not be dragged back because some politician or bureaucrat wants to be seen to be saving his constituency from dangerous toys. I do not want to and I do not want you to give them an excuse.

At the moment we are a small almost politically invisible group but burning and exploding things raises our visibility in an undesirable way.

The growing popularity of electric flight means that flyers unfamiliar with the hazards of LiPoís are reading rave reviews, by more experienced people, about this wonderful technology that lifts your flying to a new level. They want it and unless they know it can hurt them they will get it with out knowing how to handle it.

To achieve a balance and slow down the headlong dash into this technology, by those who have not yet educated themselve's on the downside of the technology, a dramatic illustration such as the flaming photo is required to restore the balance

In my view a degree of paranoia now which results in a healthy respect for these marvellous power sources will save us grief and possible intervention in the future.

Fly donít fry.




Note1
I do not know what % of the LiPo market electric RC product is but my suspicion is that it is a small % and if the regulators said no cells to be sold without protection then the LiPo producers would comply to protect the large volume markets.
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Old Oct 15, 2003, 11:15 AM
Space Coast USA
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Space Coast
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whanderson
I see you signed on just a few weeks ago and therefore probably have not been following the 2+ years of lipo development in the R/C arena. Please do a search for 'lipo fire' and see the problems that have occurred. In the beginning, some were very strong on promoting how safe these cells were and that this chemistry was no more or less dangerous than other battery chemistries. I think we all know different now.

Maybe these pictures should be added?

http://www.rcgroups.com/forums/showt...ght=lexus+fire
http://www.rcgroups.com/forums/showt...t=funtana+fire
http://www.rcgroups.com/forums/showt...ghlight=rocket
http://www.ikarus-modellbau.de/ubbth...b=5&o=&fpart=1
http://www.rcgroups.com/forums/showt...ight=lipo+fire
http://www.rcgroups.com/forums/showt...hreadid=160086
http://www.rcgroups.com/forums/showt...hreadid=160079
http://www.rcgroups.com/forums/showt...hreadid=160551

The damage is easy to see but no one had ever seen what an actual LiPo ignition looked like. Thanks to DNA, we can now appreciate the magnitude of the ignition and how these fires started.

hoppy
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Last edited by hoppy; Oct 17, 2003 at 01:34 PM.
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Old Oct 15, 2003, 01:51 PM
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Walled Lake, MI, USA
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>> if the regulators said no cells to be sold without protection then the LiPo producers would comply to protect the large volume markets.

And we would go back to our previous practice of buying surplus cell phone packs, ripping off the protection circuits and keep on flying.
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