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The real dangers of Lithium Ion batteries.......


Guest Maj Millard

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Interesting pic of that model fire, but no prize for the chemistry sain.

 

You could do an identical chemical equation for sodium, that is, 2Na +2 H2O = 2NaOH +H2+heat

 

Now common salt is nearly half by weight sodium, but that doesn't mean that common salt is flammable even if mixed with water. All my friends who are going on cruise ships would notice if the ocean caught fire.

 

In batteries and in the sea, lithium and sodium respectively are in ionic form and this is quite different to metallic form.

 

 

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Bruce, you display a lack of knowledge of the combustible nature of sea-water. This is in fact a known problem: see: http://www.thegoonshow.net/scripts_show.asp?title=s07e21_insurance_the_white_mans_burden

 

SEAGOON:

 

You mean you're offering me free of charge the deeds to the English channel?

 

GRYTPYPE:

 

He heard you Moriarty.

 

MORIARTY:

 

Do you accept the English channel then, le channel englais?

 

SEAGOON:

 

Yes. I only hope I can live up to it.

 

GRYTPYPE:

 

I'm sure you can Neddie. However, one slight formality Neddie. For your own protection of course, the jokal style of protection, you must insure it lad.

 

SEAGOON:

 

Insure it against what?

 

GRYTPYPE:

 

Fire Neddie

 

MORIARTY:

 

Yes, fire Neddie. And fortunately for vous we happen to be strolling insurance agents of no fixed percentage.

 

I think we ought all to realise that changing to a Li-whatever battery might be an insurance risk...

 

 

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At the very least....ignoring everything else you need to be damn sure you have "Authority" to make the change. If its 24, or used online for training then unless your aircraft OEM allows, in writing, the substitution of Li(anything) for the current Battery then you probably don't have the authority to change it......

 

I seem to recall that J refused to allow 10ply tyres as a replacement for the standard 6 ply......if they wont do that then good luck with a Battery chemistry change!!!

 

Andy

 

 

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I know, how about a chemistry that will eat away at your aircraft should the case split, produces combustible gasses when charging and discharging, is loaded with toxic materials, can have internal shorts that cause cells to fail, do not like cold weather, will go flat all on their own in a couple of months, can boil dry if overcharged, and will fail completely if discharged to lower than 50-60% of their capacity repeatedly? Sound familiar???

 

We are used to dealing with lead acid batteries and have come to accept their limitations and safety issues.

 

With LiFePO batteries we have a safer solution. As stated they are disposable without causing environmental hazard, their electrolyte is stable and non toxic and will not eat through your metalwork, they release no combustible gasses while charging and discharging, are relatively immune from the low temperature issues, due to their low internal resistance heat up less than other types of batteries for the same load applied, and have a depth of discharge down to 20% before needing to be recharged allowing a safety margin for "engine out/alternator out" gliding with all the fast glass panels people have these days, AND THEY WILL NOT SUSTAIN A FIRE under any circumstances.

 

Just because you are not familiar with them, does not mean they are a bad idea.

 

As a side note, most of you are sitting with a Li ION battery inches from your crown jewels as we speak......but you have come to accept that as "normal". Would you really go digging around in your pocket looking for a burning lump of lithium quickly enough to prevent injury?

 

 

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  • 5 months later...

Since leaving the master ON and damaging a battery, I have put in a buzzer to sound if the master is ON while the mags are OFF, and I have also put in a digital voltmeter on the panel. Now, as soon as the new battery has recovered from starting I turn off the master switch ( this is always well before takeoff) and isolate the battery in flight from any draw or any charging current. There are a few big capacitors between the positive and negative rails, and the alternator thinks these are the battery and so does the radio etc.

 

The new LiFePO4 battery is showing no signs of puffing up ( 7 months use).

 

Now that the fire-ban season is ending, I'm going to the farm to try to set the old LiFePO4 on fire or at least fuming.

 

Here's what I plan:

 

1. Charge it up and do a dead short. I'm not sure how to do this safely... suggestions welcome.

 

2. hang it on a fence and shoot it.

 

3. stab it with a blade on a stick.

 

4. Put it in a hot bonfire, possibly in a tin can, to see if it smokes a lot.

 

What I expect to happen from no 4 is that the plastic will melt and wet goo will ooze out but not catch fire.

 

Any ideas of what might be a good test of the fire risk of this battery? And yes I am willing to spend the time to try to prove they are safe.

 

 

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Guest Maj Millard

Bruce,

 

You may test all you like, however actual in- flight service testing in this country alone has already given us one fatality (WA), and at least one very lucky escape with a cockpi full of very toxic white smoke and two very lucky occupants (SE Qld).

 

The standard charging systems on most of our engines are simply not comparable with these batteries.

 

 

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You should deliberately overcharge it, and if that produces no faults, deplete it with a continuous starter motor load.

 

If the battery has the cell monitoring wires available, a voltage check of each would be useful. They become hazardous if the cell voltages get out of range during overdischarge or overcharge, thats why most systems, both Lipo and LiFeP04 are said to require cell balancing during operation or cell conditioning at least periodically.

 

We've had a large Lipo pack built recently for an offroad EV and installed a BMS (Battery management System) in the battery case for this. the prototype battery has run perfectly well without any BMS or conditioning system applied and cell voltages are still perfectly matched.

 

https://app.ntsb.gov/investigations/2013/boeing_787/UL/NTSB_Presentation_at_UL_Battery_Summit.pdf

 

yes this is just the ordinary Lipo system not LiFeP04 which is a safer type of lipo battery which you have. so the things to test for is its ability to fail through overcharge or overdischarge which would be common with a Jabiru regulator/ dynamo system if BMS is not used

 

and whether a battery meltdown is bad enough to make a fibreglass fire take hold

 

leave the guns and knives tests to mythbusters

 

 

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I plan to use a LifePo4 battery in my Jab., and have changed over to the CAMit alternator which has a proper regulator and (as far as I am aware) does not suffer the spikes of the standard Jab. system. I believe that will also give me better voltage regulation for running the iPad, as well as the harmonic balancing it affords, so I see it as a win/win all around.

 

 

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I used an Antigravity for years. No issues. Now I use an EarthX; Inbuilt BMS. Not cheap though. I certainly had to have a lighter battery for W and B or add weight else where.

 

I am very specific about how I treat the battery. It is disconnected when not in use to prevent any parasitic drain.... Though the BMS would disconnect if it went under voltage.

 

The EarthX have been used extensively in Snow mobiles (same rotax charging system) and the Alaskan State troopers fit all theirs with them.

 

 

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Half an hour with Mr Google searching for explosion/fire/smoke/toxic/fumes etc + Lipo/Lithium polymer/Lithium Ion etc and then searching for explosion/fire/smoke/toxic/fumes etc + LifePO4/Lithium Phosphate/Lithium Iron/Lithium ferrophosphate etc - and then filtering the results to get rid of the content from those who don't know the difference between them ... for me produced hundreds, or perhaps thousands, of 'events' on Lipo/Lithium Ion and exactly zero 'events' for LifePO4/Lithium Phosphate/Lithium Iron. I couldn't find a single reported fire, smoke, explosion or other 'event' for a LifePO4 battery/accumulator on the entire internet, can anyone else find any?

 

That tells me something about the real-life operational dangers of each type especially considering that the LifePO4s are used in competition motorsports and so are presumably of as small capacity as possible and therefore working hard during cranking, use and charging, and are also subject to regular impact trauma, vibration and g/acceleration forces, whereas Lipos are predominantly used well within their supposed capacity on electronic devices without high-drain periods or significant shock events and they still have a large percentage of failures. In high-drain usage such as RC models Lipo failures become even more prevalent and destructive.

 

To resist change from lead-acid batteries just because those have been used for decades, and only because LifePO4/Lithiumferrophosphate batteries have a name (though not chemistry) that is a little similar to Lithium Ion, with respect, suggests to me that some people might have a rather Luddite attitude toward advancement. Add that the LifePO4s provide a massive improvement in power and energy density/weight and that they don't have a dangerous or corrosive electrolyte such as lead-acids do, and you'd be missing some terrific benefits that could be gained by changing to a new product.

 

A search for 'lithium iron phosphate dangers' (that's iron, not ion!) brings up loads of informative and helpful articles from industry sources, like this one -

 

The LiFePO4 batteries are the safest type of Lithium batteries as they will not overheat, and even if punctured they will not catch on fire. The cathode material in LiFePO4 batteries is not hazardous, and so poses no negative health hazards or environmental hazards. Due to the oxygen being bonded tightly to the molecule, there is no danger of the battery erupting into flames like there is with Lithium-Ion. The chemistry is so stable that ...

 

 

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Personal experience.

 

LiFePO4 battery (Shorai brand) installed approx 18 months ago in my Shadow Streak, when I installed a new blue head Rotax 582.

 

Connected using standard Rotax regulator.

 

Just completed 100 engine hours - thus 100 battery hours.

 

Zero problems, cranks the engine in the middle of a cold winter's morning with no problems.

 

Temperature of battery after an hours flight is not even warm to the touch.

 

Your mileage may vary....

 

 

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  • 9 months later...

I,m thinking of putting the hobby king zippy flight max lifepo4 (see attached pic) as a replacement to my odyssey. At $125 and 1kg. The price and weight and various advantages make it an attractive choice. I would like to hear from members that are using this battery, specifically, in a Jabiru 230D, how they have physically installed this battery and their experience in using this type of battery and any other helpful comments that I should be aware of. Cheers

 

image.png.d16652f91a917185edf874144a6d9ea5.png

 

 

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As I said above....I have consistently used Lifepo batteries in aircraft for a number of years. They were of the brands Antigravity and EarthX. I have used all variants of LiPo/Lifepo4 etc in hobby use for RC aircraft for many years as well. I have had no issues with the brands I used in my aircraft but (given my experience with RC hobby batteries) would not recommend using the RC variants because you really need do need something to act as a shut off in low or high voltage or balancing cells type situations. The EarthX has a BMS inbuilt for that purpose. The best option IMHO.

 

Unless weight is an issue (my issue) I do not think they are worth the expense/risk. If you must use one then choose the EarthX brand - very expensive but built for purpose.

 

 

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