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Lithium Ion Phosphate Batteries – to use or not to use?


horsefeathers

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Latest email from RAA includes this from Technical

 

Message from Technical

 

Lithium Ion Phosphate Batteries – to use or not to use?

 

An article in next months’ Sport Pilot magazine covers the issue of whether or not to use Lithium Ion batteries in light aircraft powered by Rotax or Jabiru engines. Both manufactures advise against the use of these batteries and that aircraft owners should only being going in accordance with the requirements detailed in the manufactures handbook for their specific aircraft.

 

I am concerned that Tech Manager does not know the difference between Lithium ION and Lithium IRON Phosphate batteries. Following manufacturers handbook is obviously the correct thing to do, but posting confusing tech advice is less than helpful

 

 

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Lithium ion

Lithium IRON Phosphate batteries are a subset of Lithium Ion batteries. The ones causing all the problems are called "Lithium Ion" batteries in the form of "Lithium Cobalt Oxide". To avoid confusion LiFePo4 should really be called Lithium Ferrous Cobalt rather than Lithium Iron Phosphorous

 

 

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Lithium IRON Phosphate batteries are a subset of Lithium Ion batteries. The ones causing all the problems are called "Lithium Ion" batteries in the form of "Lithium Cobalt Oxide". To avoid confusion LiFePo4 should really be called Lithium Ferrous Cobalt rather than Lithium Iron Phosphorous

Let's try that again. LiFePo4 is the good one and should be called Lithium Ferrous so that it doesn't sound the same as Lithium Ion. Anyway, Kyle got in a nutshell.

 

 

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I've had LiPo's in models for at least ten years and they DON'T go poof, well none of mine have. I've had dozens for years.

 

Even so, I haven't put them in my plane but have put in a LiFePO4 which has saved about 5 kg and it now starts even better than with the Odyssey.

 

5kg weight saving gives safety benefits for anybody who thinks safety is the most important thing in life.

 

Personally, I've had a gutful of "safety". I like the way it takes off faster and climbs a bit better.

 

 

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Bruce I have to disagree. I have seen this with my own eyes as I was there 30 mins after this happened and I took these photos. I removed all Lipoly batteries from my turbine models after this incident and have only ever charged the Lipoly batteries outside the model and in the open away from anything that can catch fire. I use them in electric RC models and thats all. My jets are all powered by LiFE batteries and 98% of other jet guys are the same.

 

This is a mate of mine who had a beautiful Avonds F15 with a Simjet 16kg thrust turbine in it. It had only 1 Lipoly battery in it and it was used for the fuel pump battery. The night before its maiden flight all the nicad batteries and the 1 Lipoly battery were being changed. The brand new Futaba transmitter just happened to be sitting on the top of the model as well. The transmitter was a new MZ some $3000 worth and the model was worth around $20,000. The one Lipoly which was a new battery and had been previously charged as the engine had been run several times before to test all the systems etc so it wasnt as if it hadnt been used before. My mate put it on charge and went into his house to have tea...after he had tea about 45 mins later he went back out to the shed and this is what greeted him. In the ashes you can see what is left of the turbine and also you can even see the outlines of the transmitter sticks.

 

Can you imagine if this happened inflight while you are in the aircraft. It is a 4000 deg magnesium style fire

 

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Those pictures I posted on RCUniverse thread many years ago. It was the start of a lot of people around the world getting them out of their models when charging them so it would not happen to them. I just checked the old post it was done on 18/3/2009

 

 

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I can remember Maj. going on about those batteries about two years ago yes two (2) ago and how he sent a letter into the tech.department regarding such.

 

Well I have to say they are not real quick on getting the information to the members or was he ignored?

 

KP.

 

 

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The RAA article unfortunately confused the two type of Li batts. They called a Lithium Iron Phosphate battery a Lithium ION Phosphate. Pity, that is one article that should have been technically correct.

 

 

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I think Maj meant well but he didn't fully understand that there are 3 different types of "lithium" battery.

 

Personally, I find it very hard to cope with authority where their great power is not matched by equal technical competence.

 

Referring to that RAAus article confusing battery types, it illustrates how you get better technical stuff on this forum than from RAAus and CASA put together.

 

In the meantime, my prize for telling me how to set a LiFePO4 on fire, using any means at all, has never had a contender. Certainly not from RAAus or CASA.

 

 

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The RAA article unfortunately confused the two type of Li batts. They called a Lithium Iron Phosphate battery a Lithium ION Phosphate. Pity, that is one article that should have been technically correct.

Major thread drift, but relevant. I'm currently writing a POH for my home-built Jodel and I need help with the section on "In case of fire..."

So far I have: Shut off fuel, close cowl flaps (to cut off airflow) and flood engine bay with fire extinguisher.

 

Perhaps David, with your unique qualifications you could venture some suggestions. I've read of pilots who have dived to pick up airspeed to "blow out" an engine bay fire. Aside from VNE considerations, is this tactic worth considering?

 

 

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Major thread drift, but relevant. I'm currently writing a POH for my home-built Jodel and I need help with the section on "In case of fire..."So far I have: Shut off fuel, close cowl flaps (to cut off airflow) and flood engine bay with fire extinguisher.

Perhaps David, with your unique qualifications you could venture some suggestions. I've read of pilots who have dived to pick up airspeed to "blow out" an engine bay fire. Aside from VNE considerations, is this tactic worth considering?

Fire is one of the most terrifying things in an aircraft.

Kill the 'Master' electrical switch as well Lyle. If you don't have one fit one and make sure it disconnects the alternator as well or modify the alternator and kill the excitation circuit which will kill the alternator output. Electrical fires are likely and the Master switch is an essential safety device.

 

If you have an engine extinguisher make sure the engine compartment is sealed (cowl flaps closed) and Fuel and electrics 'off' before you dump it. Remember dilution of extinguishing agents ocurrs rapidly at speed; you will need a large amount well dispersed around the engine. Use it wisely. It may be your first defense, but I wouldn't hang my hat on it working unless the design is good.

 

A dive with the cowl flaps open and fuel and electrics off may work to extinguish the fire as a last resort. A rapid side slipping decent even past Vne would be my choice if the fire was established; side slipping will tend to keep the heat off the fire wall. If there is no fuel or power it seems reasonable that you could have a good chance of getting it out. In any case there will be little left of the aircraft if the fire is established at altitude so Vne wouldn't rate too much unless I got the fire out then I would care about speed.

 

Then you have to find a suitable landing spot ....

 

Just some loose thoughts on the matter. No one really knows what would happen other than it would be a very unpleasant experience.

 

 

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Try to remove combustibles from the fire area. Fuel pumps off and selector off. It could be oil also from a busted pipe so consider stopping engine rotation

 

Electrical Isolate/ If you know it's electrical after isolating you may choose to troubleshoot depending on what reliable indications you have of what is happening.

 

Main aim often is to get on the ground quickly but don't crash as you are already on fire. I personally doubt you will ever blow a fire out by diving. It might have worked with old rotaries or you suffer pain for less time from being burned alive.

 

To prepare your POH reference as many similar types as yours and adopt what is appropriate. Nev

 

 

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Old Koreelah, did you notice your discrepancy about the cowl flaps? If you are going to blow out the fire then they should be open as David says.

 

IF it is a fuel fire, shutting off the fuel valve and letting lots of air blow through will put it out. But there are other possibilities as Nev says.

 

 

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Old Koreelah, did you notice your discrepancy about the cowl flaps? If you are going to blow out the fire then they should be open as David says...

Bruce it was a case of either close them and use extinguisher, or open them and dive. Which should come first, given that the extinguisher has a limited supply of retardant?

 

 

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If you can seal an area from oxygen the retardant works better. This would entail slow flight and well sealed cowl gills. Engine areas are divided into zones. The one the engine is in is not regarded as sealed or really able to be. (with Pistons, a jet is fairly well sealed). Sometimes the accessories compartment is more manageable. (pistons)

 

By the way if you have certain kinds of engine fire on start up. (pistons) where Fuel puddles in the exhaust and catches fire you continue to try to start the engine and burn and blow away the excess fuel. Nev

 

 

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