EMERGENCY SAFETY ALERT

[Dino Spadaccini]

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

[Matthew]

Dino

Thanks for the heads up. How many people use these types in there nitro heli?

[Buzzin Brian]

This is the reason I choose to stay away from them. Can they be used relativly safely? Yes. But to me there are to many variables for me to even go there. I will just fast charge if neened, and stay with Nicads. But that is me.

[Matthew]

I get about 3 flights out of my packs before I need to recharge. Plus I like the time in between to sit and BS with the other guys or watch them fly. What fun would it be if I had to sit there and wait for my heli go up in flame(if you saw the vid. it only took a few seconds for the Lithium battery to go nuclear) and I didn't get any BS done in the processes. Or better yet, one of the plank guys do the touch and no go into the weeds at the end of the runway.

[Sar]

I can do about 5 flights safely on the 4000mAh but I usually recharge around three. I've thought about using LiPoly. I like the technology, but stay away from it because I've had some big crashes in the past that probably would have ripped open a LiPoly.

[Spitfire_mk5]

I'm a LiIon (duralite) convert. yes they require a bit of saftey but its the price for the far superior performance.

Plus they can be handled safely look at your cellphone/pda/laptop and try not to crash as much :P

[Matthew]

Yea, but I don't fly my cell/laptop/(don't have a pda) around. At least not yet. I think your right though Spitfire there is danger in all things we do. Diligence and safe operation is what is needed. The AMA is, I think, just trying to give some of the less serious few a wake up.

[Tom Fiddler]

I believe Mongo is on to something here.
While I don't believe Lipo's are any more dangerous than a quart of gas
You have to remember that the AMA seems to make more decisions based on insurance liability than what is best for the hobby.
Just read the presidents column every month. All he talks about is insurance.
People fear what they don't understand. Get educated about Lipo's, Pay ATTENTION to what you are doing and you wan't have a problem.
I remember when 30% nitro was crazy talk, and who would need a 90 size engine?

[WillJames]

Thanks for the reality check Tom! Your right. Know what you use, practice it safely. Yea you may have to read the directions or ask it on HF. :)

I sure LOVE my duralites!! For a guy who now rarely gets to go flying, I just charge when I get home from flying, and then they sit there still fully charged and ready for a LONG time, I fly when I can. :D

[MicroMan]

Are there any alternatives to LiPos in the electric arena.

[DebianDog]

Are there any alternatives to LiPos in the electric arena.

Well you CAN run Nicads or Lithium but it will be less power and in the case of Lithium more expensive. Not an electric "pro" so maybe other could shead some more light on this.

[Tonystott]

Are there any alternatives to LiPos in the electric arena.
Not for a Trex. But seriously, the doomsayers have exaggerated the risks with LiPos. Provided you are diligent in following the correct procedures, they are perfectly safe.

My safeguards are not too onerous...

Only use the charger for LiPos. This rules out the possibility of using a setting for other types of cells. Use a separate charger for other types.

If charging different size/configuration LiPo packs, charge the smallest ones first (most accidents happen because the pack on charge is smaller (either less cells andor lower capacity) than the settings so it gets overcharged)

Place the pack in a fireproof container while charging (I use an old steel saucepan on a non-flammable surface, with nothing flammable above)

Double check settings before connecting to the power source

Balance the packs often (I actually only ever charge through the balancer)

If you want to be super-safe, a clever idea is to get a large ziplock plastic bag, fill it with dry sand, and place it over the fireproof container. Should the unthinkable happen and a pack ignites, the plastic will melt and the fire will be smothered by the sand)

The above suggestions are probably not any more complex than those that should be followed when handling liquid fuel....

[askman]

and we are seeing new safer options like A123M1 and Emoli. I am moving to A123M1 cells for most of my e-heli. they are almost as safe as nicad/nihm and close to lipo in performance at some weight penalty.

[Cryofix]

and we are seeing new safer options like A123M1 and Emoli. I am moving to A123M1 cells for most of my e-heli. they are almost as safe as nicad/nihm and close to lipo in performance at some weight penalty.


I was just about to say that, I feel the future is going to be in these batteries and Lipos will be phased out becasue of slight saftey concerns and price.

However, the problem does not fall on the batteries a the saftey concern it falls mainly on the chargers and the people that use them, more specificlly the all in one charges, if you leave Li-Po on a Ni-* charge you run a serious risk of fire, or if you do not pay attention to your batteries and then charge them.


Other than those 2 things there is not many other issues you should be concerned with with lipos, as they are allowd to be sold so someone thought they would be safe enough for the mass market.


99% Lipo safey is being informed about the battery itself, and obeying the warnings

[MeSSoR]

oke..so the lipo is safe when handeled with caution,

what if you leave a lipo for like 5 months or longer? like on a holiday..you won't be able to charge it...

will it die or burn from not being charged when empty.. just wondering.

Dennis



( Most Dumb questions are the ones that aren't asked :lol: )

[Pinecone]

Lipos have very low self discharge rates. A couple of sties I have looked at mention long term storage at about 1.2 charge.

Also, lipos can lose capacity through sheer age, without even being used or abused.

[kgfly]

oke..so the lipo is safe when handeled with caution,

what if you leave a lipo for like 5 months or longer? like on a holiday..you won't be able to charge it...

will it die or burn from not being charged when empty.. just wondering.

Dennis


Nope, it's perfectly safe to leave a lipo on the shelf for months on end. It won't go thermo and start a fire, although for peace of mind they should always be stored in a fire-proof container (eg saucepan, flower pot, pyrex casserole, ammo box etc).

Don't leave it discharged for months on end or it may fall below a rechargable level. For optimal long-term (ie more than a few weeks) storage charge to approx 70% capacity before placing it in storage.

[6victor6]

If you want to be super-safe, a clever idea is to get a large ziplock plastic bag, fill it with dry sand, and place it over the fireproof container. Should the unthinkable happen and a pack ignites, the plastic will melt and the fire will be smothered by the sand)


That is a great idea!...

[Pinecone]

Long term storage is typically 3.8 - 3.85 volts per cell. And that is what you will typically find new packs at.

There is a video of using a concrete block with a bag of sand over it. It worked well. But since the smoke and fume is pretty nasty, you shoud charge damaged packs outside anyway, so who cares if the jet of flame shoots up?

[Chris Blom]

Good information here.One question, what kind of fire extinguisher should you have on hand in case of a lithium ion battery fire.Was it a class 'D' fire extinguisher?Also for charging a lithium battery there is a "Liposack" battery bag that you charge the batteries in that contains the battery fire should it occur. It is sold by RC Hover.

[kgfly]

Or you can make your own "lipo sack" from a typical kitchen fire blanket sold at hardware stores. In either case they will contain the fire but not the smoke.

[uluaz]

I wonder if eventually the TSA and/or FAA will eventually ban large Lipo packs on airline flights.

[Chris Blom]

Just a note,to put out a Lithium Ion Battery fire use class D fire extinguisher [metal/sand] .There are a variety of class D extinguishers available, however, for use at flying sites where lithium fires may happen, only two of the types should be used: powered copper metal or graphite-based powders.- March 2007 issue of the AMA Insider,AMA's National Newsletter.

[Trooper Sam]

Where the heck do you buy one of those? It sure ain't at Costco. :)

[Chris Blom]

Trooper Sam- I will have to look into where you buy a class D fire extinguisher.