REGARDING: AMA Safety Committee Announcement - Lithium Battery Hazard

[dogon1013]

I just recieved this announcment from the AMA:

EMERGENCY SAFETY ALERT

Lithium Battery Fires
Lithium batteries are becoming very popular for powering the control and power systems in our models. This is true because of their very high energy density (amp-hrs/wt. ratio) compared to NiCads or other batteries. With high energy comes increased risk in their use. The, principal, risk is FIRE which can result from improper charging, crash damage, or shorting the batteries. All vendors of these batteries warn their customers of this danger and recommend extreme caution in their use. In spite of this many fires have occurred as a result of the use of Lithium Polymer batteries, resulting in loss of models, automobiles, and other property. Homes and garages and workshops have also burned. A lithium battery fire is very hot (several thousand degrees) and is an excellent initiator for ancillary (resulting) fires. Fire occurs due to contact between Lithium and oxygen in the air. It does not need any other source of ignition, or fuel to start, and burns almost explosively.

These batteries must be used in a manner that precludes ancillary fire. The following is recommended:


Store, and charge, in a fireproof container; never in your model.

Charge in a protected area devoid of combustibles. Always stand watch over the charging process. Never leave the charging process unattended.

In the event of damage from crashes, etc, carefully remove to a safe place for at least a half hour to observe. Physically damaged cells could erupt into flame, and, after sufficient time to ensure safety, should be discarded in accordance with the instructions which came with the batteries. Never attempt to charge a cell with physical damage, regardless of how slight.

Always use chargers designed for the specific purpose, preferably having a fixed setting for your particular pack. Many fires occur in using selectable/adjustable chargers improperly set. Never attempt to charge Lithium cells with a charger which is not, specifically, designed for charging Lithium cells. Never use chargers designed for Nickel Cadmium batteries.

Use charging systems that monitor and control the charge state of each cell in the pack. Unbalanced cells can lead to disaster if it permits overcharge of a single cell in the pack. If the batteries show any sign of swelling, discontinue charging, and remove them to a safe place outside as they could erupt into flames.

Most important: NEVER PLUG IN A BATTERY AND LEAVE IT TO CHARGE UNATTENDED OVERNIGHT. Serious fires have resulted from this practice.

Do not attempt to make your own battery packs from individual cells.

These batteries CANNOT be handled and charged casually such as has been the practice for years with other types of batteries. The consequence of this practice can be very serious resulting in major property damage and/ or personal harm

Safety Committee
Academy of Model Aeronautics

5161 E Memorial Drive
Muncie, IN 47302

[dogon1013]

Below is the E-mail that I sent in response, What are your thoughts on the matter?

To whom it may concern,

I believe your statements are blown WAY out of proportion and will result in scaring people instead of informing them.

Lithium batteries have been in use for many many years in cell phones, laptop computers, and many other places. (In fact you probably have one in your cell-phone right now) It is improper to target Lithium batteries exclusively, any battery (lead acid, Nicd, Nimh, and even drycell) can result in a fire if not used properly. In fact they all have warning labels on them explaining this.

Please do not aim this warning at only lithium batteries, It suggests that they are much more dangerous than other batteries, which is not the case. I appreciate your warning and you make appropriate suggestions, but PLEASE RE-SEND YOUR WARNING stating that ALL BATTERIES CAN CAUSE FIRES WHEN IMPROPERLY USED, NOT JUST LITHIUM BATTERIES. To ignore all other battery types in your warning gives the impression that all other battery types will-not, or are less-likely to, cause fires. This is totally un-true and unsafe.


CONCERNED MEMBER, and avid Lithium battery user (in cell-phones, and laptops, and PDA's and RC planes)

[jpv11]

Toby,

I also received this email. What concerned me most is the following:

"Use charging systems that monitor and control the charge state of each cell in the pack. Unbalanced cells can lead to disaster if it permits overcharge of a single cell in the pack. "

Does this mean that all chargers that do not monitor each cell are unsafe? I was unaware of this issue with a single cell. For instance, I know many of us use the Hobbico II to charge LiPos. Is this safe or not? If not, why do they sell the charger for use with LiPos? I don't remember the directions stating "for use with lithium ions, unless one cell in a pack is unbalanced, in which case this charger will start a fire of several thousand degrees and burn down Orlando." but maybe I just missed that part. It doesn't really matter to me, because I had decided to buy a Triton (am I correct in assuming it monitors individual cells?), but if the information in the AMA letter is correct, it seems to me highly irresponsible of the manufacturer to sell a product that doesn't monitor individual cells. I mean, if I drop my cell phone the next time I plug in the charger I don't expect the phone to burst into flames and burn down my house if the battery has been damaged.

Another thing I found interesting was this statement "Store, and charge, in a fireproof container; never in your model." yet in the same letter they state that "A lithium battery fire is very hot (several thousand degrees)". What fireproof container can withstand several thousand degrees? For instance, a quick web search turned up several fire proof lock boxes, but they were rated at 1700 degrees. Anyway, I'd be interested to hear what you (and others) think of this.


John V.

[ctdahle]

I think as LiPo's become more common, their use will trickle down from the tinkerers and tweakers who understand exactly how the work and how to use them, to average schmucks who just want to plug them in and fly without thinking about it.

I think the LiPo safety warnings are similar to the warnings to use a chicken stick or starter rather than your fingers to start an IC engine, you often can get away with it, but you can also suffer a hell of a cut or lose a finger.

LiPo's are still too pricey and have too much of a smell of black magic for me and what I am flying, but I am likely to be the first guy around here to try them out. I guess when I do start experimenting with them, I'd rather start from the overly safe side and take precautions that are not necessary, than start without any precautions and learn by burning up planes and houses.

[dogon1013]

There has been MUCH more discussion of the safety "warning" in the power systems area of RC groups, if you have more concerns or questions regarding Lipo's check it out here:

http://www.rcgroups.com/forums/showthread.php?t=223587

I guess it is very different at our field than other places. i would say at least 50% of the people that fly at our field own and use Lipo batteries, One of them did burn his vehicle in a charging related fire about a year ago. No fires have been started at the field that i know of, there have been some smoldering packs though.

Lipo packs are more sensative to over-current than Nicd and Nimh packs. but are they more dangerous, probably not.

The thing that really bothers me about the AMA warning is that they do not seem to understand Lipo's at all, and are just putting a blanket warning out that is nearlly impossible to follow.

Are you going to stop charging your cell-phones over night because of this warning? according to the AMA you should charge your cell-phone in a fire-safe box, while watching over it, and never overnight. If you drop your cell-phone you should immediatly remove the battery and watch it for an hour, then discard it. This is just impracticle, and idiotic, and it really makes the AMA look bad.

[J_R]

The alert sent by the AMA was written by Don Lowe, chairman of the AMA Safety Committee. He wrote it in conjunction with Fred Marks. Fred is the FM in FMA Direct.

The first responses to the Alert were pretty much negative, from the guys that DO understand Li technology. What appeared on all of the net groups, since the first hours, makes it clear that not everyone was aware of the potential hazzards involved with the technology.

If it saves some houses or cars, it has more than fullfilled it's function, IMHO.

As to phone, computer, and camera batteries, etc. that is part of the point. Commercial units have built in circuts to protect from over charging. A thermistior is engineered into each pack and each pack has a special charger designed for it. Something that will not happen in our very small part of the Li-Poly market. It's just not financially fesible to make a charger for every configuration we dream up, and as a result, we need to understand the basics and potential consequences of ignoring those basics. Education is the answer and the Alert pointed out the need for that education.

[dogon1013]

good points J_R

I guess i take it for granted that we have very Lipo educated members at our "club". Information is always good, i just worry about mis-information and exageration.

What about the Lithium and oxygen combining in the air statement. As far as i understood it there is no pure lithium metal in these batteries (it is combined with some other material, kind of like the sodium in Salt). and therefore the lithium won't be the cause of the fire, like it is suggested in the AMA statement.

[J_R]

I'm not a battery expert, but, I had a little college chemistery. WITH HEAT Li will plate out of the battery and when combined with O2 will burn. Remember that when you overcharge any battery (or even a single cell) the overcharge produces heat, and thus the problem. There are some good articles, some written by Fred Marks on Red Schoefield's RC battery clinic site. I have not been on the site in a while, but IIRC Marks addresses your question.

http://www.rcbatteryclinic.com/

[Hal Ray]

J_R I'm always glad to see you reply to something here.

I think that most of us would have liked it better if the AMA had used a bigger pool of experts then just the one.

HRH

[J_R]

This all started to come to a head at the Toledo show. I now know that Don Lowe talked to Red Schoefield as well, in the preparation of the alert. There may very well have been others. Marks was the only one mentioned to me initally.

[FHHuber]

Where is having a safety officer harmful?

Its fairly simple to make a safety container for charging LiPos. See the battery forum. A common crock-pot works. The ceramic is fire-proof and will contain the battery so it can't jump somewhere.

Since you can pick up a crock pot at a garage sale for as little as 20 cents... (more often about $2) Its not asking too much to have the guys charging LiPos to stick them in a pot.

*********

Does it NEED to be a rule? YES! most guys that use the LiPos don't see the logic and are starting to have batteries burst causing cars to catch fire...

Maybe all you need is the club to buy 4 or 5 crock pots from garage sales so the pots are available at the field and then require the E-flyers to use them.

It wouldn't take anything other than watching that wmv file to convince me that its pretty dumb NOT to put the LiPo where it can't cause a fire if it bursts. But then I am much smarter than the average modeler.


_____________________________

starting with the simulator will HELP. But it won't replace getting some in-person assistance while learning. It will let you practice making the same mistakes all day but you won’t crash your rc plane.


Edit:too much crack-pot

[J_R]

Where is having a safety officer harmful?

Its fairly simple to make a safety container for charging LiPos. See the battery forum. A common crack-pot works. The ceramic is fire-proof and will contain the battery so it can't jump somewhere.

Since you can pick up a crack pot at a garage sale for as little as 20 cents... (more often about $2) Its not asking too much to have the guys charging LiPos to stick them in a pot.

*********

Does it NEED to be a rule? YES! most guys that use the LiPos don't see the logic and are starting to have batteries burst causing cars to catch fire...

Maybe all you need is the club to buy 4 or 5 crack pots from garage sales so the pots are available at the field and then require the E-flyers to use them.

It wouldn't take anything other than watching that wmv file to convince me that its pretty dumb NOT to put the LiPo where it can't cause a fire if it bursts. But then I am much smarter than the average modeler.


_____________________________

starting with the simulator will HELP. But it won't replace getting some in-person assistance while learning. It will let you practice making the same mistakes all day but you won’t crash your rc plane.


????????? I think that is a crock.

[FHHuber]

JR

Thanks for pointing that out. Sometimes I just have to many tpoys. I will fix. I apologize for the inconvenience.


_____________________________

starting with the simulator will HELP. But it won't replace getting some in-person assistance while learning. It will let you practice making the same mistakes all day but you won’t crash your rc plane.

[sinbad]

It all comes down to the 1C rate or higher for charging. I charge all my LiPo s on a Triton using the 100ma.rate. Sure it's an overnight charge just like we charge our radios so what's the big deal? Any fast charge creates heat and heat no matter what type battery is harmful (warping or shorting out the plates in the battery).Never fast charge a battery thats hot after a deep discharge,- R/C car batteries really get hot. Have a few extra packs and slow charge after use and you will get long use from them. I have e-mailed Thunder Power (LiPo)and they said if you aren't in a big hurry slow charging is the way to go.
Sinbad

[pda4you]

I charge all my LiPo s on a Triton using the 100ma.rate. Sure it's an overnight charge just like we charge our radios so what's the big deal?

ACtually I think unattended charging is dangerous - do you sit there all night with your packs?

You would be better off to do 1C and stay with the battery.

Mike

[sinbad]

Mike,
Being retired allows me to charge during the day while in the shop so it's not an issue for me. I don't think any of my battery packs took longer than 4 hours to recharge,I guess mainly because I never get them so low that the ESC shuts down the motor once the pack gets to the cutoff point. Monitoring is essential if you use the 1C rate or higher. I just like the safety factor that 100ma gives me. Something would really be wrong if I had a problem with this slow rate.
Sinbad

[50+AirYears]

In the course of my job, I get to work with most of the technologies at a different level than I do as a modeler. Any of the types of batteries can start a fire. I even had a 3.5 amp lead acid gell cell blow up during a low current trickle charge. Sent chunks of metal over a twenty foot radius. The Lithium manufacturers have been sending out warnings about the potential fire hazard since they started making them available. Lithium batteries are less forgiving of mishandling than most of the others.

Just a few days ago, there was a news story on TV about a youngirl who was badly burned when her cell phone battery ignited. It was turned off and in her pants pocket at the time. The battery was completly destroyed.

The warning needs to be taken seriously. Lithium ignites violently when in contact with oxygen. All thats needed is to pay attention when charging, don't charge in the model or put the cells on a flammable surface while charging, and when you are getting ready to charge, look the pack over for dents, scratches to the case, or bulges. All batteries generate pressure inside during charging, and scratches, dents, and bulges are signs of weaknesses in the case that could split open under pressure. And a split case means oxygen gets in. Remember, just because something hasen't happened doesn't mean it isn't going to, it just means it might be getting ready to. Any battery charging has it's hazards, lithium battery charging is just a bit more unforgiving.

If you like them, use them. Just pay the right amount of attention to what your doing with them. The AMA is not crying wolf.

[Flying kevin]

hahah that be funny if you crash your plane and the whole thing caught on fire by a battery instead of a fuel tank and engine explosions.

Kevin