cautionary tale Lipo fire

[fidspeed]

Just a warning to al lipo users (most of us now)
On of our local drivers (a senior experienced member) dropped in to see us last night with a tale of woe

he had placed his batteries on charge in a lipo sack in his kitchen ready for racing popped to fuel station to fill his road car came back to find his house on fire :thumbdown: .I have seen pictures it was a mess .Fire sevice estimated 15 more minutes and he would have been homeless insurance repairs will be thousands as the acrid smoke damage was extensive

the reason for the lipo fire is unknown it could have have been a faulty lipo or charger or charger setting or other other human error .We will never know and its not worth debating here IT HAPPENED!!
What we do know is he will never leave a lipo on charge unattended again and will ensure there in a lipo sack or pouch

regards dave Fid

[Aire valley]

That's almost unbelievable".:cry:..... and you say that the lipo was in a safe bag..? Probably never find out why, but would be really interesting to know..

[Jayk]

The error wasnt the fault itself, but leaving em charging unguarded.
The lipo bag probably did its job as a short term retardent, i dont know the safe usage of them or ip whatever but im guessing its not gonna put a fire out.

[fidspeed]

The error wasnt the fault itself, but leaving em charging unguarded.
The lipo bag probably did its job as a short term retardent, i dont know the safe usage of them or ip whatever but im guessing its not gonna put a fire out.

Yes you are quite correct it was just ,poor judgement at worst negligent at best, I wasn't wanting to start a debate, particularly just remind everyone how dangerous our particular use of lipos can be and what can result from being a little complacent at times or just momentarily "off guard"

Bee safe fellow racers having seen the photos I wouldn't wish that on anyone (self inflicicted and possibly preventable though it was)

dave fid

[OneKiwi]

IT happened at EOS as well

https://scontent-b-ams.xx.fbcdn.net/hphotos-prn2/t1.0-9/1982188_10152105155974900_739519881_n.jpg

[mark christopher]

Hi Dave out of curiosity can you find out which charger was used?

[mattr]

I really really really really worry about people who think a Lipo sack is a suitable alternative to actually supervising your high discharge lipos during charging.

Guy I work with left his 6s cell charging in the garage while he went to pick his daughter up from nursery.

Lost the entire contents of a double garage.

Maybe this should be a sticky.

[Chris56]

Thanks for the "heads-up". I agree blame or cause shouldn't really be debated here, simply that it happened and the consequences can be pretty bad.

Having witnessed a LIPO fire a week ago, I know tat LIPO bags will only contain the fire for 5 seconds max - long enough to grab it and throw it out of harms way but not long enough to prevent considerable damage being done.

I often charge LIPOs at home and never leave the house when I do so. Due to recent events im considering using an aluminium box to charge them in (with the bag also) so that I can at least leave the room in confidence.

[mattr]

FWIW Lipo powered hybrids use around 15-40 kilos of Lipo cells, most have a dedicated temperature management system to stop them getting too hot OR too cold) only the very smallest piggy back off the AC/cooling system, they also have custom designed charge/discharge management systems (rather than a stock, generic Chinese circuit board), they also sit inside 30-50 kilos of high strength steel or composite armoured casings with what can only be described as blast vents in case of Lipo failure.

Yet people still rely on a Lipo sack.

[zoaman]

Its probably a good wake up call to all of us who don't take charging lipos seriously enough. now ive seen that picture I will make sure I take even more care(time) when charging them.
thanx for the heads up.

[fidspeed]

Its probably a good wake up call to all of us who don't take charging lipos seriously enough. now ive seen that picture I will make sure I take even more care(time) when charging them.
thanx for the heads up.


thanks fellas for the positive response from all of you that's all it is a stark reminder of what can happen it doesn't matter whose fault it was whether its faulty equipment or user error /awareness thats too blame

all the victims probably thought it wouldn't happen to them IT DID !

I think some of us have become a tiny bit complacent with the advent of lipos and the benefits and not so aware of the drawbacks

In no way am I suggesting cells were any less dangerous or lipos are inherently dangerous

thanks to all who have read this thread and be safe as you can

regards dave

[MattW]

Dave, I think you're absolutely correct about complacency having slipped in. The thread the other week about the BRCA rule update proves that for me. So it's good to just remind people that these things aren't 100% safe (and let's be honest, very few things are).

I'll be honest and say that I'm actually surprised there haven't been more "big problems" in the last couple of years.

LiPo fires WILL happen guys, lets just "do the right things" and hopefully the damage can be minimised.

[SlowOne]

Thanks for the "heads-up". I agree blame or cause shouldn't really be debated here, simply that it happened and the consequences can be pretty bad.

Having witnessed a LIPO fire a week ago, I know tat LIPO bags will only contain the fire for 5 seconds max - long enough to grab it and throw it out of harms way but not long enough to prevent considerable damage being done.

I often charge LIPOs at home and never leave the house when I do so. Due to recent events im considering using an aluminium box to charge them in (with the bag also) so that I can at least leave the room in confidence.Do not grab a LiPo sack with a problem in it and throw it anywhere. This advice assumes that you can disconnect it from the charger, which is usually difficult, and that you have somewhere to throw it that is in any way 'safe'.

By the vast majority, LiPos are used indoors, so there is nowhere to throw them. Make sure that at every meeting there are at least two buckets of (preferably kiln dried) sand available in the pit area. If a LiPo gets a thermal runaway, douse it in sand immediately, and then leave it alone for at least 15 minutes.

This idea that you can pick up a sack with a LiPO in it undergoing thermal runaway and transport it anywhere has already badly burned one racer - don't do it. Make sure that your meeting has easy access to fire buckets filled at least 75% with sand and at the slightest sign of a LiPo in serious distress, dump the contents on it.

This is clearly what did not happen at the EOS meeting pictured in the thread, hence the large amount of damage.

Dave, I think you're absolutely correct about complacency having slipped in. The thread the other week about the BRCA rule update proves that for me. So it's good to just remind people that these things aren't 100% safe (and let's be honest, very few things are).

I'll be honest and say that I'm actually surprised there haven't been more "big problems" in the last couple of years.

LiPo fires WILL happen guys, lets just "do the right things" and hopefully the damage can be minimised.That last line is the key - LiPo fires are entirely predictable due to the inability of the industry to manage completely the manufacturing process. As the fires are inevitable, prepare for the inevitable.

A sack holds thing up for enough time to get the bucket of sand and douse the fire. Be prepared!

[mark christopher]

Best thing I have seen is the turnigy lipo bunker. http://www.hobbyking.com/hobbyking/store/__24647__turnigy_lipo_bunker_lipoly_safety_charge_ box.html

Slow one is not a fan, but I use one at home, it controls any potential fire better than a sack, but it does vent the fumes, I'm sure the guy in Dave's 1st post would rather have had a house full of fumes over the fire.

Some will follow this with its faults (slow one) but sack or bunker I know which I trust I'm not sure if this bunker is ok for BRCA use, defo worth while for home use.

https://www.youtube.com/watch?v=rusHrUSMmcw&feature=youtube_gdata_player

The biggest failure of a lipo sack is the failure to put the lipo in fully and fully seal the Velcro.

[Chris56]

I have looked at them.

Slowone - for the record I am not advocating throwing the sack, just highlighting what somebody did when they saw the flames.

[Origineelreclamebord]

Thanks for the heads up everyone. I'd like to add a story warning you that LiPos aren't even always safe in a state of rest. A fellow club member had one of his LiPo batteries burst at night after it had not been used for three weeks!

As far as my knowledge goes, the battery was neither under or overcharged when it went into storage and there were no prior signs that the battery might have been damaged. I do know he demands a lot of his batteries (the electronics he runs and his driving style) and that it was not a very new battery, but the fact that it happened makes it a statistic possibility.

It's probably a (way) less likely scenario that it happens with a LiPo in rest, but I would NEVER EVER recommend you to store your LiPos in the open or in a LiPo bag. I use an Ammo Box to store my batteries, you could also use a small safe of course.

Speaking of the LiPo fires themselves, Lithium is an alkali metal. It reacts heavily to water (especially as temperatures elevate), but it cannot burn without any oxygen. However, the batteries may contain oxide materials, and in a fire may supply themselves with (limited) amounts of oxygen.

Anyway, what's important to know is that water won't extinguish the fire (and may in fact fuel a stronger reaction), smothering helps but may not instantly stop the fire (because of oxides in the battery), and lowering the temperature will decrease the speed of the reaction. And of course lastly, if you can contain the fire inside something (an ammo box, safe or something else), you can give yourself time to get away or cool the container (to try and reduce the severity of the reaction).

[/tobys]

So, whats the consensus on how to store Lipos? The realization that they can, in rare and unfortunate circumstances, spontaneously combust is enough for me to reconsider my current storage and handling.

Airtight, metal container for storage?
Where does this get stored, as we are told that they shouldn't be anywhere too cold (which rules out storing outside)?
Lipo pouch whenever connected to charger as a common sense approach to safety, rather than just to appease the race director (!)
Correct/Safest way to dispose of old lipos?
etc
etc

I think there is lots of good info/advice to be shared/discussed.

[Neil Skull]

Thanks for sharing Fidspeed,
I hope anyone thinking of leaving their lipo unattended will think twice!!
I don't leave any phone or laptop or anything on charge unsupervised! I wont even leave my phone on charge overnight! Thats wheter lipo or not! its just not worth the risk.

[Neil Skull]

I have never heard of a lipo igniting in storage before!!! that's worrying!
I know they can swell and fail if left in cold garage or hot tin shed.

I keep my lipos in an aluminium field box under the stairs away from heat extremes.

http://www.rcmodelcentre.co.uk/Aluminium-Field-Box/prod_5228.html

[mark christopher]

If your that worried I defo would not store multi lipo in one container if one goes,you will have one hell of a chain reaction, also not in case sealed box, your them making a bomb. Something has to give under this pressure created.

Me I'll take appropriate care but I'm not going to loose any sleep.

[fidspeed]

Thanks for all the input fellas

i guess what we are learning from this is we all need to be a bit less complacent than we have been and maybe take a few more precautions

lipo accidents are maybe a bit more frequent than we thought and "airing" them here should help awareness

We dont need a debate on lipos/sack/bunkers/pouches and their various merits and shortcomings .

lets just be a bit more vigilant even watching our "pit neighbours "lipo charging while we happen to be racing or marshalling

regards dave

[SlowOne]

I have looked at them.

Slowone - for the record I am not advocating throwing the sack, just highlighting what somebody did when they saw the flames.Sorry - it's always difficult to interpret what people say on a post! Yes, best advice is don't do that!

Anyway, what's important to know is that water won't extinguish the fire (and may in fact fuel a stronger reaction), smothering helps but may not instantly stop the fire (because of oxides in the battery), and lowering the temperature will decrease the speed of the reaction. And of course lastly, if you can contain the fire inside something (an ammo box, safe or something else), you can give yourself time to get away or cool the container (to try and reduce the severity of the reaction).The only extinguisher that will work on a LiPo fire is a copper powder one, but these are as rare as hens teeth. Excluding the oxygen is the key, and containing the shower of hot ashes. That is why sand is your friend.

So, whats the consensus on how to store Lipos? The realization that they can, in rare and unfortunate circumstances, spontaneously combust is enough for me to reconsider my current storage and handling.

Airtight, metal container for storage?
Where does this get stored, as we are told that they shouldn't be anywhere too cold (which rules out storing outside)?
Lipo pouch whenever connected to charger as a common sense approach to safety, rather than just to appease the race director (!)
Correct/Safest way to dispose of old lipos?
etc
etc

I think there is lots of good info/advice to be shared/discussed.My suggestion would be to put the LiPos in a metal container, preferably steel, with vents to let the gases out so the lid doesn't come off as the gasses from the LiPo expand. If you are concerned about having that resting on a non-concrete floor, then put the container onto a large ceramic tile. Ceramic is a great insulator. HTH :)

(Also, check your charger. When disconnected and re-connected, does it default to the same charge settings you used last time? Some don't! Try every way of inadvertently disconnecting your charger, and then reconnect it and check the settings. If it doesn't go back to your usual LiPo settings, stick a big note on it saying CHECK SETTINGS to remind you.)

[andrewc]

My RC stuff currently lives in my garage; is there a recommended temp range for storage?

I never leave mine unattended when charging or discharging, but am a little surprised to hear one has burst just sitting in storage.

Am I correct that a FIRE can only occur during charge or discharge?

[Mike Haswell]

Am I correct that a FIRE can only occur during charge or discharge?

You would be incorrect on that - just because you aren't charging or discharging doesn't mean there isn't anything going on. A recent case at the Snowbirds saw a pack go up even though it had finished its discharge - was still hooked up to the charger though. Temperature fluctuations can make things happen too. I had a pack which had a slight bit of swelling and then one warm day I found that it had swelled further and popped the cause whilst not in use!

When we first started using lipos I read up on a few cases of lipo fires and one involved a bloke's plane going up in flames in his garage overnight. What they reckoned happened in that case was that the temperature had dropped overnight and that some condensation had caused the pack to short out.

[dale]

My RC stuff currently lives in my garage; is there a recommended temp range for storage?

I never leave mine unattended when charging or discharging, but am a little surprised to hear one has burst just sitting in storage.

Am I correct that a FIRE can only occur during charge or discharge?

Lipos don't like to be too hot or too cold, so the garage is pretty bad due to the temperature extremes and fluctuations. As Mike notes above a change in temperature can cause issues.

In the house in an ammo box is a safe storage solution while keeping the temperature stable.

[SlowOne]

My RC stuff currently lives in my garage; is there a recommended temp range for storage?

I never leave mine unattended when charging or discharging, but am a little surprised to hear one has burst just sitting in storage.

Am I correct that a FIRE can only occur during charge or discharge?A fire is the unavoidable outcome of the pack fault allowing anode and cathode to touch each other creating a short circuit. It is more vigorous the higher the charge in the cell, but it is not something limited to it being on charge or discharge.

Above a range of 70°C to 90°C the Li-ion graphite anodes will start to self-heat. At about 130°C the separators will start to melt at which point the positive and negative electrodes will touch causing a short circuit. Now the temperature rises very quickly, the heat cannot be dissipated and the positive electrode burns releasing more oxygen that feeds the fire that results.

For fully charged cells, these temperatures can reach in excess of 600°C (1,110°F); case temperatures for lithium-iron phosphate cells are generally lower. The temperature rise is driven by reactions of the electrodes with electrolyte and release of stored energy.

Depending upon the environment around the cell, the cell vent gases may ignite. The gases are not “self-igniting.” There must be sufficient oxygen in the surrounding environment to sustain combustion of hydrocarbons and there must be a competent ignition source to ignite the vent gases. A burning cell would be a good ignition source.

The issue is that once something goes seriously wrong, the inevitable result is a thermal runaway. Cell puffing is also a cell failure, but it is non-energetic - nothing happens catastrophically.

I hope some information makes people more aware. This is not intended to scare anyone, just make people aware of the situation so they can take whatever action they need to for the risks they want to avoid. Judging by the posts above, peeps are aware and take steps to avoid risk. :thumbsup: HTH :)

[maineyak]

Worrying about my lipo pack sat in me transmitter now.....:cry:

[beale]

You would be very unlucky if you had a problem at those levels of discharge, do you remove it to charge? And between events? I have had a lipo puff from being left fully charged for 2 weeks due to a DNF, that's when I started storing them storage charged in a lipo sack.
After reading this thread have bought a steel electrical cabinet as a home charge/storage bunker

[suparajicon]

Thanks for sharing Fidspeed,
I hope anyone thinking of leaving their lipo unattended will think twice!!
I don't leave any phone or laptop or anything on charge unsupervised! I wont even leave my phone on charge overnight! Thats wheter lipo or not! its just not worth the risk.

I agree with you.

[Danny]

Useful to be reminded that Lipos need a fairly large amount of respect with the way they are charged and stored. Someones already asked what the charger was and id be interested to know more bout the routines of these failed Lipos, like what kind of amps/C were they being charged at usually? What % was left in them during storage? And what approximate temperature were they stored at and for how long?

[beale]

Just been looking at the specs of the elangears Elan R used in the EOS pic, it isn't capable of rates I would of expected problems, but a highly discharged race cell then instantly put on a 15A charge could be.
Obviously there is component failure, poor connections ect to add as possible causes

[SlowOne]

Useful to be reminded that Lipos need a fairly large amount of respect with the way they are charged and stored. Someones already asked what the charger was and id be interested to know more bout the routines of these failed Lipos, like what kind of amps/C were they being charged at usually? What % was left in them during storage? And what approximate temperature were they stored at and for how long?In the two LiPo fires I have sat next to :wtf: the charge rates were close to 1C. The issue with chargers is that some may default to an NiMh program when switched off, or disconnected inadvertently (power loss, fuse blown, etc.)

The temperature and storage state are not relevant to the issues. It is what has happened inside the cell that allows the anode and cathode the touch and short out. This can be caused by the growth of crystals known as dendrites. This is most common if a deep discharge happens, but age also comes into it. Dendrites are hard metal crystals that bridge the anode and cathode causing a short.

The most common fault is that during manufacturing the chemical parts of the manufacture are not easy to control. For any number of reasons there can be a fault inherent to the cell and there is nothing you can do about it. once the separators (about 70 microns thick, or half the thickness of a human hair) are hot and start to melt, there is nothing you can do to stop the inevitable.

In any given week over 1000 people are racing LiPo in the UK - it is probably five times that across the world? They charge their cells four times, say. That's 20,000 charges a week, over a million a year. I think I may be conservative on that, but if it's about right then we have maybe five or seven incidents factually recorded over three years - or about a one in 400,000 chance it might be you. I suspect the odds are longer than that.

Sensible precautions are the order of the day. Trying to find the exact conditions that lead to a failure is futile - the source of the faults that lead to catastrophic failure are seeded in the manufacturing process and you have no idea if they are there or not.

1C charge and discharge, store between 5C and 30C in a sack and/or metal container (steel is best) at the recommended storage charge - good advice to follow. HTH :)

[Danny]

Epic post SlowOne, cheers for clearing that one up!