A new worry for me- are Lipos safe?

[paul devereux]

Since starting the hobby a year ago, I've accumulated a few Lipos- 3s  2200s ( I disposed of one in a battery recycling bank as it got a bit too large and puffy to be used) and a few smaller ones for self-build projects (1 and 2 cells). I usually recharge on a coffee table, and store them wherever (usually one charged in my plane ready to take out the next morning. None of them are puffy or damaged, though I have learnt on this forum I have probably damaged their longevity by running them for 10 plus minutes per flight.

A work colleague has said Lipos are prone to spontaneously combust, and are a fire hazard? I find this hard to believe, as they can be delivered through the post without special precautions and there aren't warnings about this. What is the consensus- are Lipos safe or unsafe?

 

[aidan mcatamney]

Never leave them unattended while charging.  I got my house burned to the ground while charging a lipo battery in 2007.  .  Always charge them inside a fireproof bag or box.  

[Philip Lewis 3]

I'm of the mind that there are two schools of thought on this, those that don't realise how dangerous LiPO's CAN BE and those that are paranoid about them.

 

My (considerable) experience with a lot of high capacity high cell count LiPo's is that I can't see what would literally cause a LiPo to suddenly combust, there would have to be some outside circumstances.

 

In my experience LiPo fires are almost universally caused by misuse, charging at the wrong cell count, shorting out the terminals or whatever, I certainly having set fire to a small RX 500 mah pack by shorting the terminals wouldn't ever charge any in a house or for that matter anywhere where the fire would cause any damage other than to the LiPo or charging equipment myself.

 

I also always keep my LiPo's at storage charge only which at least would limit the potential energy release.

 

All batteries are potentially dangerous if misused inccorectly, a battery after all contains stored energy and if unreleased the wrong way can be dangerous.

 

IMHO you just need to be careful but not paranoid about them, having said that there is a container ship on fire due to a suspected electric car malfunction, not a LiPo but stil a lithium battery.  

[Phil Green]

10 minutes ago, Philip Lewis 3 said:

I'm of the mind that there are two schools of thought on this, those that don't realise how dangerous LiPO's CAN BE and those that are paranoid about them. 

 

So Philip if you feel that you're not paranoid about them, that leaves you in the first group 🙂

I agree there seem to be two schools of thought, but a different two - those who heed someone who has personally suffered greatly from a lipo fire, and those who completely dismiss the possibility simply because it hasnt happened to them  🙂

 

Yet...   🙂

 

[Allan Bennett]

I am not paranoid (I think), but I do take care with my LiPos.

 

• I store them at 50% charge or less -- usually the 25% or so charge that they finish at after a flight.
• I store them in a set of fire-resistant 'pigeon holes' constructed out of plasterboard (half-hour fire resistance).
• I always balance-charge them in fire-resistant LiPo sacks the day I'm going to use them.
• I keep a fire extinguisher not far from the charging station to deal with any spread of the fire (probably impossible to extinguish a burning LiPo itself).
• I transport them to the field in a fire-resistant carry bag.
• Any that are physically damaged or puffing excessively I discharge to zero volts with a car tail light bulb before disposing.

[Graham Bowers]

5 hours ago, Philip Lewis 3 said:

SNIP

My (considerable) experience with a lot of high capacity high cell count LiPo's is that I can't see what would literally cause a LiPo to suddenly combust, there would have to be some outside circumstances.

SNIP

The phenomena of lithium dendrite growth and the potential to cause internal short circuits between electrodes is  well documented, and not fully understood as far as I can tell. Since first becoming aware of this, I've read quite a bit. My understanding is that this wouldn't be noticed by the user, until a catastrophic event occurred, that would appear to be spontaneous.

 

Whilst not fully understood, it would seem "best practice" as we understand it offers mitigation, but not elimination of issues.

[GrumpyGnome]

@paul devereuxthere's another thread about this.....

 

https://forums.modelflying.co.uk/index.php?/topic/53013-who-has-first-hand-experienced-a-lipo-fire/&tab=comments#comment-960784

 

makes for interesting reading.

[leccyflyer]

7 hours ago, paul devereux said:

Since starting the hobby a year ago, I've accumulated a few Lipos- 3s  2200s ( I disposed of one in a battery recycling bank as it got a bit too large and puffy to be used) and a few smaller ones for self-build projects (1 and 2 cells). I usually recharge on a coffee table, and store them wherever (usually one charged in my plane ready to take out the next morning. None of them are puffy or damaged, though I have learnt on this forum I have probably damaged their longevity by running them for 10 plus minutes per flight.

A work colleague has said Lipos are prone to spontaneously combust, and are a fire hazard? I find this hard to believe, as they can be delivered through the post without special precautions and there aren't warnings about this. What is the consensus- are Lipos safe or unsafe?

 

There have been many threads discussing lipo safety on this forum most recently this one

 

https://forums.modelflying.co.uk/index.php?/topic/53013-who-has-first-hand-experienced-a-lipo-fire/&tab=comments#comment-960784 

 

 

and the definitive lipo fire safety thread has been running on RCG for more than 15 years. 

 

https://www.rcgroups.com/forums/showthread.php?719116-Lipo-Fires-Are-Real!!!!

 

I'm rather surprised that you aren't aware of the warnings, which are widely publicised regarding carriage and delivery of lithium polymer batteries, that the Royal Mail ask if your parcel contains batteries or other flammable articles when you go to the post office with it and that many RC retailers will only send lipos with a courier.

 

There has just been a report on BBC Radio news that a fire safety charity is campaigning for lithium ion battery fire safety certification to be mandatory and administered by an independent agency, rather than left to lithium battery manufacturers.

 

 

[GrumpyGnome]

There's a similar article on BBC News web site .....

[Brian Cooper]

To answer the original question in the thread title, NO, they are not 100% safe.  They are a fire risk. 

 

Treat them with respect, and don't charge them unattended. 

 

Most recharging goes without a hitch but it only has to go awry once to create a (flaming)  catastrophe. 

[leccyflyer]

Indeed and certainly don't ever keep a charged lipo in a model or charge a lipo in a model, thereby surrounding it with flammable material.

[PeterF]

BMFA battery safety booklet can be found at

https://britishmfa.sharepoint.com/sites/public/Handbook Update/Forms/AllItems.aspx?id=%2Fsites%2Fpublic%2FHandbook Update%2FHandbook%2C Gudiance %26 Codes of Practice&p=true&ga=1

 

Another cautionary thread on here.

https://forums.modelflying.co.uk/index.php?/topic/47237-charging-lipos-a-lesson-learned-the-hard-way-and-how-the-big-guff-met-its-end/

 

Join a club, you will get to know lots more information from interaction with other members and absorb knowledge just be being there.

[Jon H]

Given the nature of the outcome should one decide its had enough i lean towards paranoia when it comes to lipo's and treat each one like an unexploded bomb. Its a simple risk/reward sort of situation and i work on the basis that its better to be over cautious than burn the house down as there is no stopping it once it starts. 

 

 

 

 

[Learner]

London fire brigade saying that e bike fires are now causing call outs 1 in 2 days.

190 injured and 8 killed through fires caused by batteries is being reported.

I'm sure most probably caused by poor quality and abuse but a sobering thought.

[toto]

I must admit Paul, I'm a bit surprised that you never knew about the dangers of LIPO batteries. Conversations rage all over the hobby on forums and clubs almost on a daily basis.

 

I'll be honest, I'm a bit scared of using them and I must have around 20 of various types but go on the basis that just treating them with respect and being aware of the dangers will give you a reasonable chance, however, you could be one of the unlucky ones that fall foul of them and without apparent reason or misuse ..... end up with a bad experience.

 

I never leave them unattended whilst charging ..... usually always in the shed. I try to go on a self imposed ban on having them in the house. 

 

I dont like having fuel stored on the shed either but I am slowly coming to the opinion that it may be the lesser of the two necessary evils. I'll see how I get on with my glow models and of happy with them ..... and the mess and smell, may phase put lipo's where possible and only use them in specific circumstances for example my twin's where I think electric is the most operationally safest way to go in terms of engine 's cutting out etc.

 

Bottom line ..... treat them with care and respect, store them in explosion proof bags.

 

Toto

[David perry 1]

9 hours ago, aidan mcatamney said:

Never leave them unattended while charging.  I got my house burned to the ground while charging a lipo battery in 2007.  .  Always charge them inside a fireproof bag or box.  

Me too about 3 years ago.  Are they safe? Yes but treat them like primed bombs. 

 

Lipos are driving me back to glow.  

[Engine Doctor]

It was discussed at local model shop a few days ago. A club member came in saying he was getting rid of all of his eletric stuff  by order of SWMBO.  Apparently he broke the golden rule of charging indoors and unattended and badly smoke damaged his conservatory. Fortunately the battery was in a metal box do he was able to shut the lid and throw it out the door onto the lawn where it burnt itself out.

Take reasonable precautions and uou should be fine. Ive decided to store all of mine in a dry insulated box kept inside a metal dustbin from now on. We keep on hearing about these so called solid state safe batteries that dont catch fire but the sceptic in me thinks that manufacturers have invested so heavily in the current lithium batteries and anything new is bought up and buried for the future ?

[Nigel R]

10 hours ago, paul devereux said:

What is the consensus- are Lipos safe or unsafe?

 

Safe and unsafe.

 

Various things increase the risk of something going wrong. At some point, that means a battery would stop being safe and start being unsafe, and I can't tell you what that point is. Anyway, factors are:

 

Age.

Use pattern.

Charge state.

Exact chemistry type.

 

The internal degredation can be partially measured. With the right kit. Really, to predict when cells are going wrong, you need lifespan operating data, and we just don't do that because it requires specialist kit that can assess how cells perform and can track that against the same cell's performance history. Oddly enough, that's expensive to do.

 

One of the internal degredations (dendrite growth) can cause the 'spontaneous' combustion issues that have been reported. Doesn't even have to be actively charging. If there's enough of a short to raise the temperature inside (and that can take some time) to the point where combustion starts, then it's game over. Yes, that circumstance is unlikely, but, it does happen.

 

Point of note, big lipos have lots more stored energy, and lots more combustible material.

 

I will admit, this whole topic is one reason I stick to small stuff for electric flight. The smaller batteries are financially feasible to simply replace every few years. Newer batteries are by definition in better condition than older ones.

Edited July 27, 2023 by Nigel R

[Jon H]

Meanwhile in the North Sea....https://www.bbc.co.uk/news/world-europe-66310280 

 

An electric car is suspected as the cause of the fire and even if it wasnt you cant put the ship out now the electric cars are burning. 

[Cuban8]

I wouldn't worry too much about the storage of glow fuel. Keep it in the manner that the manufacturer suggests and use common sense. Glow fuel is far safer than highly volatile petrol and one rarely hears of fires happening at petrol filling stations despite the potential  either for someone to get it wrong when filling their vehicle or during delivery by tanker. Amazing really when one considers the millions of gallons of petrol that are sold to an often unwary public. 

I haven't tried it and don't suggest that anyone does out of idle curiosity, but I'd bet a tenner that a lighted ciggy dropped into a pot of glow fuel would see the ciggy extinguished and the glow fuel otherwise untouched.  Not what you get with petrol as its vapour mixed with air would ignite instantly..........witness petrol used as a barbecue or bonfire lighter. https://www.youtube.com/watch?v=BCXjlshi770  Quite an explosion apart from the fire!

I'm going to review my Lipo storage regime - I have them stored in metal boxes in my detached brick garage so not a risk to my main property. However, a fire in my garage would still be catastrophic and cause a lot of damage to equipment and tools etc.

I think a small separate storage unit not unlike which can be bought for garden tools is worth considering. I'm lucky enough to have plenty of room to site it out of harm's way and clear of other buildings.

Don't know, would welcome comments.

Edited July 27, 2023 by Cuban8

[Dickw]

It seems to me that the more recent Lipos don't burn as fiercely as the original versions did.

I had a Lipo fire in flight four years ago (long smoke trail was the give-away!) and managed to land the model safely, remove the wing (3 x bolts) and shake out the Lipo onto the ground. Only a couple of cells of the 10s battery had actually burnt, and the model was flying again the following week after replacing some burnt wiring.

Anyone know if the chemistry has changed to make them burn less fiercely?

 

Dick

ps it was a newish battery and the cause of the fire was probably a weak/dodgy cell in a pack that was being pushed beyond its normal rating.

[Nigel R]

53 minutes ago, toto said:

dont like having fuel stored on the shed either but I am slowly coming to the opinion that it may be the lesser of the two necessary evils.

 

I like having lots of lipos stored in the shed a lot less than I like storing a few gallons of glow.

[Nigel R]

9 minutes ago, Jon - Laser Engines said:

Meanwhile in the North Sea....https://www.bbc.co.uk/news/world-europe-66310280 

 

An electric car is suspected as the cause of the fire and even if it wasnt you cant put the ship out now the electric cars are burning. 

 

The irony is that automotive batteries do actually the kind of monitoring systems that I've mentioned, so once in use, they are now far safer than anything we do in hobby land. Plus they have a different style of cell and the rate they are charged and discharged at is much kinder to the cell. 

 

I seem to remember reading statistics that suggest electric cars now suffer fires less frequently than ICE cars.

[Cuban8]

2 minutes ago, Nigel R said:

 

The irony is that automotive batteries do actually the kind of monitoring systems that I've mentioned, so once in use, they are now far safer than anything we do in hobby land. Plus they have a different style of cell and the rate they are charged and discharged at is much kinder to the cell. 

 

I seem to remember reading statistics that suggest electric cars now suffer fires less frequently than ICE cars.

I wouldn't put very much faith in certain statistics when there is a very motivated and vocal lobby pushing a particular agenda.

[leccyflyer]

12 minutes ago, Cuban8 said:

I wouldn't worry too much about the storage of glow fuel. Keep it in the manner that the manufacturer suggests and use common sense. Glow fuel is far safer than highly volatile petrol and one rarely hears of fires happening at petrol filling stations despite the potential  either for someone to get it wrong when filling their vehicle or during delivery by tanker. Amazing really when one considers the millions of gallons of petrol that are sold to an often unwary public. 

I haven't tried it and don't suggest that anyone does out of idle curiosity, but I'd bet a tenner that a lighted ciggy dropped into a pot of glow fuel would see the ciggy extinguished and the glow fuel otherwise untouched.  Not what you get with petrol as its vapour mixed with air would ignite instantly..........witness petrol used as a barbecue or bonfire lighter. https://www.youtube.com/watch?v=BCXjlshi770

I'm going to review my Lipo storage regime - I have them stored in metal boxes in my detached brick garage so not a risk to my main property. However, a fire in my garage would still be catastrophic and cause a lot of damage to equipment and tools etc.

I think a small separate storage unit not unlike which can be bought for garden tools is worth considering. I'm lucky enough to have plenty of room to site it out of harm's way and clear of other buildings.

Don't know, would welcome comments.

If you have the space a separate, self contained storage container makes sense, but since the highest fire risk is still during charging, which would still need to be done in a place with a power supply and where the charging can be monitored. I'm considering adding such a container, outside my workshop, tucked away out of harm's way. If it were for year round use it would also need to be well insulated, to keep a reasonable temperature at all times. Storing lipos in a hot, enclosed, container in summer is just asking for trouble.