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Posted

these are not lipo batteries.  they are using LiFe PO4  that don't tend to explode or burn like the lithium ion or lithium polymers did / do.  

The ones that are shown above also have built in changers so they will balance the cells and they are meant to be used in powersports applications.  If is works in a bike or snogo it will be fine in our birds running 2 strokes.

:BC:

 

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Posted

these are not lipo batteries.  they are using LiFe PO4  that don't tend to explode or burn like the lithium ion or lithium polymers did / do.  

The ones that are shown above also have built in changers so they will balance the cells and they are meant to be used in powersports applications.  If is works in a bike or snogo it will be fine in our birds running 2 strokes.

:BC:

 

Are you referring to the battery in the video? The battery in the video is indeed a Lipo. https://en.wikipedia.org/wiki/Lithium_polymer_battery

 

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these are not lipo batteries.  they are using LiFe PO4  that don't tend to explode or burn like the lithium ion or lithium polymers did / do.  

The ones that are shown above also have built in changers so they will balance the cells and they are meant to be used in powersports applications.  If is works in a bike or snogo it will be fine in our birds running 2 strokes.

:BC:

 

Are you referring to the battery in the video? The battery in the video is indeed a Lipo. https://en.wikipedia.org/wiki/Lithium_polymer_battery

 

You might want to go back and actually watch the video and see what it says on the battery when he opens the case....  LiFe PO4

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Posted

these are not lipo batteries.  they are using LiFe PO4  that don't tend to explode or burn like the lithium ion or lithium polymers did / do.  

The ones that are shown above also have built in changers so they will balance the cells and they are meant to be used in powersports applications.  If is works in a bike or snogo it will be fine in our birds running 2 strokes.

:BC:

 

Are you referring to the battery in the video? The battery in the video is indeed a Lipo. https://en.wikipedia.org/wiki/Lithium_polymer_battery

 

You might want to go back and actually watch the video and see what it says on the battery when he opens the case....  LiFe PO4

If you take the "Fe" and the "4" out of the info on the battery you get "LiPO" and that's why I included a link to the Lithium polymer battery. Lipo is a common abbreviation for Lithium Polymer batteries. And yes I did see it in the video and instantly recognized it as an RC hobby battery. The title of the video even states it's a Lithium battery. He also mentions a protective case for the battery. He flies RC so he has played with these batteries like many of us in the RC world. Yes the device has a built in charger but he's not using it. Nowhere in the video did he plug in an adapter to the charging port on the device. He snipped off the original electronics that may or may not have been designed to prevent charging from an electrical system. I can't see the component names or I may be able to back engineer what he snipped off. I do know with a direct feed to his airplane charging system his power pack will be getting constantly charged from the alternator charging system. At the very least I'd put a cheap charging bag around the whole unit such as one of these: https://www.banggood.com/search/protective-battery-charging-bag.html

 

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Posted

these are not lipo batteries.  they are using LiFe PO4  that don't tend to explode or burn like the lithium ion or lithium polymers did / do.  

The ones that are shown above also have built in changers so they will balance the cells and they are meant to be used in powersports applications.  If is works in a bike or snogo it will be fine in our birds running 2 strokes.

:BC:

 

Are you referring to the battery in the video? The battery in the video is indeed a Lipo. https://en.wikipedia.org/wiki/Lithium_polymer_battery

 

You might want to go back and actually watch the video and see what it says on the battery when he opens the case....  LiFe PO4

https://en.wikipedia.org/wiki/Lithium_iron_phosphate_battery

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Posted

My point is the chemistry is different.  To call and treat a LiFe as a lithium ion or lithium polymer is not correct.  That is my point.  You call an apple and apple and an orange and orange.

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Safety[edit]

One important advantage over other lithium-ion chemistries is thermal and chemical stability, which improves battery safety.[13]LiFePO
4
is an intrinsically safer cathode material than LiCoO
2
and manganese spinel, through omission of the cobalt, with its negative resistance versus increasing-heat property potentially encouraging thermal runaway. The FePO bond is stronger than the CoO bond, so that when abused, (short-circuited, overheated, etc.) the oxygen atoms are much harder to remove. This stabilization of the redox energies also helps fast ion migration.[14]

As lithium migrates out of the cathode in a LiCoO
2
cell, the CoO
2
undergoes non-linear expansion that affects the structural integrity of the cell. The fully lithiated and unlithiated states of LiFePO
4
are structurally similar which means that LiFePO
4
cells are more structurally stable than LiCoO
2
cells.[citation needed]

No lithium remains in the cathode of a fully charged LiFePO
4
cell—in a LiCoO
2
cell, approximately 50% remains in the cathode. LiFePO
4
is highly resilient during oxygen loss, which typically results in an exothermic reaction in other lithium cells.[7]

As a result, lithium iron phosphate cells are much harder to ignite in the event of mishandling (especially during charge) although any fully charged battery can only dissipate overcharge energy as heat. Therefore, failure of the battery through misuse is still possible. It is commonly accepted that LiFePO
4
battery does not decompose at high temperatures.[13] The difference between LFP and the LiPo battery cells commonly used in the aeromodelling hobby is particularly notable.[cita

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Posted

My point is the chemistry is different.  To call and treat a LiFe as a lithium ion or lithium polymer is not correct.  That is my point.  You call an apple and apple and an orange and orange.

I'll give you it's a slightly different compound that's less of a fire hazard than other lithium battery compounds but it's still not a battery that can't catch on fire from extended over charging. He's got that setup to charge at lead acid battery voltages and rates. Fix that as I mentioned earlier and it might be worth a shot. The fire proof bags are so cheap and light weight that I don't see any reason to experiment without one. Unlike a car you can't pull over and pop the hood at first sign of smoke. Since many of the 2 strokes run without batteries just fine I think they show more promise over an engine that relies on a battery. Magneto systems would be another safe platform to test these with.

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Posted

My point is the chemistry is different.  To call and treat a LiFe as a lithium ion or lithium polymer is not correct.  That is my point.  You call an apple and apple and an orange and orange.

I'll give you it's a slightly different compound that's less of a fire hazard than other lithium battery compounds but it's still not a battery that can't catch on fire from extended over charging. He's got that setup to charge at lead acid battery voltages and rates. Fix that as I mentioned earlier and it might be worth a shot. The fire proof bags are so cheap and light weight that I don't see any reason to experiment without one. Unlike a car you can't pull over and pop the hood at first sign of smoke. Since many of the 2 strokes run without batteries just fine I think they show more promise over an engine that relies on a battery. Magneto systems would be another safe platform to test these with.

It would take serious abuse to make a LiFe PO4 battery catch on fire.  They will melt down, but I've seen no reports of one catching on fire.  A combination of chemistry, and a usually less dense and more robust construction  keeps the thermal overload below the combustion point.  LiPO batteries are extremely dense, only a thin layer of a polymer separates the elements, and as AKFlyer pointed out, the chemistry is prone to thermal runaway.  A little damage or thermal overload and all the layers/cells short together and release the stored energy quickly.

That said, any device/chemical that is sufficiently energy dense is dangerous.  We only think gasoline is relatively safe because we've had 100 years to find all the ways it isn't and engineering solutions for the problems.

Mark

 

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Since we r on the battery subject, Anyone ever heard a batter squeal? I have a super start battery in both planes, i have alot of trouble with them going dead over time so installed disconnect switchs, 

anyway when i crank my planes and when u have to crank it a bit more cause motor is cold, the battery stats SQEALING, took me a bit to find out what the hell it was. Parts store is worthless for help, hardly any good parts guys anymore.

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Posted

When you pull a lot of amperage out of a battery, there are a lot of chemical and thermal changes in the battery going on.  The squealing is likely a place in the battery that electrolyte gets forced through when this is going on.  Probably not a good thing, but if it hasn't quit yet, I probably wouldn't worry about it.

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Posted

Those of us that fly RC charge our batteries in fire proof containers for a very good reason. I'm not saying NOT to use a Lipo battery but if I did I'd be putting it in a fireproof battery container. They have battery charging bags that are cheap and light and you could fashion a protective case easy enough. The charging system on a normal car or airplane is not designed for the special requirements needed to properly charge and maintain a Lipo. If the charging system is altered for a Lipo battery and a fire proof box added you might end up with a safe and reliable system.

No way would I put one in my plane!!! A fire is one of the worst things that can happen in the air!!!

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Posted

When you pull a lot of amperage out of a battery, there are a lot of chemical and thermal changes in the battery going on.  The squealing is likely a place in the battery that electrolyte gets forced through when this is going on.  Probably not a good thing, but if it hasn't quit yet, I probably wouldn't worry about it.

Those chemical changes from electricity going into a battery or coming out of a battery are further bottle necked by extreme cold or heat. Here's another link to the type of battery in the video with a proper way to charge it, prevent it from being over charged and monitor it.  https://youtu.be/bj7abaCrwvI  One important factor about this type of battery is they do not like cold weather at all!

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