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Safety Alert!!

I just received the following alert from the AMA Safety Committee in Muncie... I would hope ALL users of Li-Poly batteries give it special attention.

Bill Fulmer LM AMA 4305 AVP-Louisiana

========================= 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
Reply to
Bill Fulmer
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Yes, persons who mishandle Li-Poly batteries are a fire risk. Yes, Li-Poly batteries cannot be handled like nicads or nimhs.

On the other hand, how in the world do the millions of people using cell phones with Li-Poly batteries make it through the day? Any battery technology can be dangerous if misused. Lead-acid will explode. Nicads will explode. Nickle Metal Hydride will make you sterile. (That's a joke, son.)

The problem with such sensationalism is people will become numb to it and not learn.

-- Dave Thompson

Reply to
Dave Thompson

Dave.. There was no sensationalism implied OR intended in my post.

The cold, hard fact is, as stated, Li-Poly batteries must be treated properly or they can cause serious injury to persons and/or property.

A short time back I posted a link to a film clip of a Li-Po battery being purposely overcharged to demonstrate the disasterous consequences that could occur...

Battery technology is rapidly changing, and the electric power systems are truly amazing in their scope... It's incumbent upon the user to learn about and keep abreast of the technological changes in our sport/hobby...

Cheers,

Bill

Reply to
Bill Fulmer

: On the other hand, how in the world do the millions of people using cell : phones with Li-Poly batteries make it through the day? Any battery : technology can be dangerous if misused. Lead-acid will explode. Nicads : will explode. Nickle Metal Hydride will make you sterile. (That's a joke, : son.)

One important thing that was maybe not sufficiently emphasized in the AMA article was the need to balance the packs. Cell phones typically use single cells - no need to balance. Laptops have built-in electronics to charge each cell individually. Only model fliers build serial packs and then charge them in that format. Only recently have the packs with possibility to charge individual cells appeared. Just as with other chemistry cells, repeated charge-discharge cycles in series will unbalance the pack, and this may eventually lead to some cells overcharging. Thus balancing the pack by charging individual cells, OR THE WHOLE PACK PARALLEL is required on regular basis. I've seen people use special connectors to their packs providing a pin for each terminal of each cell. With these, you can use mating connectors, in the speed controller to build the pack into serial format, in the charger to connect all cells parallel. Neat!

-Tapio-

Reply to
tapio.linkosalo

Store in a fireproof container? Why? I would think it's just as inert and harmless as my laptop and cell phone when it's not being charged or discharged.

Reply to
Frank

Yes, that is true, but cell phones come with safety circuitry that high power applications do not.

Overcharging cells or shorting them or damaging them leads to puffed up packs that pop and can cacth fire and burn fiercely.

From scanning the ezone, several planes and chargers have been destroyed by fire, one family car, and not a few workbenches. Most of these have been down to identifiable user error or pack damage, but one or two remain unexplained.

Therefore although I too find the safety-nazi approach of the AMA a little irritating, they are trying to make a real and valid point.

I suggest anyone who is concerned get the real facts from the ezone

formatting link
in the batteries and charges forum.

The basic fact is these packs WILL pop and burn if accidentally abused. The contents are NOT lithium metal - thats not the issue - but a fairly inflammable organic electrolyte. Not quite Napalm, but you get the picture.

Reply to
The Natural Philosopher

Mmm. Do you fly your laptop into the ground at 50mph? Having removed its safety protection circuitry first?

Reply to
The Natural Philosopher

Reply to
Frank

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