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Ammo box

Lipo storage

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ken anderson.18/11/2018 09:48:05
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Holes it is then.....

ken anderson..... ne..1...holes dept.

supertigrefan18/11/2018 10:29:55
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The considerations are:

1. An unsealed container will allow the gases to escape into the compartment supporting breathable air, so in layman's terms the poisonous gases from a vented container will contaminate the air you are breathing in.

2. The heat produced by a decomposing Lithium Ion battery needs to be contained to prevent the spread of that fire.

3. Any damage caused by an explosive force inside the container needs to be minimised.

"Lithium-ion battery fires generate intense heat and considerable amounts of gas and smoke. Although the emission of toxic gases can be a larger threat than the heat, the knowledge of such emissions is limited."

**LINK**

My experience with 'abused' Ammo boxes is that they will contain a detonated Thunderflash…..that's an impressive feat.

The choice is your own.

Edited By supertigrefan on 18/11/2018 10:30:26

leccyflyer18/11/2018 12:04:35
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The emission of toxic gases might be a health risk, but the greater risk is the burning down of modeller's garages, sheds and houses, of which there are many recorded instances. That's the aim of the fire containment systems being discussed.

 

Edited By leccyflyer on 18/11/2018 12:17:09

Don Fry18/11/2018 12:54:11
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Posted by supertigrefan on 18/11/2018 10:29:55:

The considerations are:

1. An unsealed container will allow the gases to escape into the compartment supporting breathable air, so in layman's terms the poisonous gases from a vented container will contaminate the air you are breathing in.

2. The heat produced by a decomposing Lithium Ion battery needs to be contained to prevent the spread of that fire.

3. Any damage caused by an explosive force inside the container needs to be minimised.

"Lithium-ion battery fires generate intense heat and considerable amounts of gas and smoke. Although the emission of toxic gases can be a larger threat than the heat, the knowledge of such emissions is limited."

**LINK**

My experience with 'abused' Ammo boxes is that they will contain a detonated Thunderflash…..that's an impressive feat.

The choice is your own.

Edited By supertigrefan on 18/11/2018 10:30:26

A thunder flash is a grown up banger. Argue until you are happy, but trying to contain a fire in a sealed box not certified or designed to contain pressure is a very bad idea. The idea is to contain the fire while you take steps, in the opposite direction, at speed.

An ammo box and it's seal is designed to keep the rain out, and be tough enough to protect the contents from damage.

David Mellor18/11/2018 14:05:58
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To me, it seems that Don makes a good point.

Ammo boxes are intended to keep undesirable things out (rain, stray sparks) not to keep occurrences  like combustion/explosion from lipo "events" in.

The volume of gas and particulates (sooty smoke, in other words) from a lipo "event" is enormous and will build up a substantial pressure if containment within a sealed box is being considered.

So the problem isn't so much to do with the release of energy,  it is more to do with a change of state (liquid gel electrolytes to gas) accompanied by a release of heat.  

Containing the heat is relatively easy inside a steel box, box containing the gas pressure is more problematic.

Most likely outcome is that the rising gas pressure will rupture a sealed ammo box without much difficulty, making a rather loud bang in the process and scattering bits.

Thunder flashes are designed to make a bang, which they do by releasing a relatively small amount of energy  in a very short time-frame (fraction of a second), not to continually produce large volumes of gas and heat over a much, much longer time frame (many tens of seconds).  In this respect a lipo-event is much closer to a flare-event than to a thunder flash event.  It is significant that HM Coastguard use thin walled steel boxes with holes to contain flares - as JD8 reported earlier.

Most offshore and coastal yachts carry a range of flares in simple screw-top, wide-neck plastic jars which are sealed against salt-water ingress.  But when a flare fails and goes off accidentally inside the jar, the heat instantly melts away part of the jar and vents the efflux and some of the heat.  But you still need to think carefully how you store the jar itself (fire on a boat at sea being potentially catastrophic).  

Here's a very visual  illustration of why the approach of sealed containment - rather than venting - may prove difficult with a system (like an ammo box) which isn't designed to cope with the large volume of gas generated (and the consequent build up of pressure).  Also, consider that the venting gas also carries away some of the heat, which might ignite adjacent batteries within the box if not released ....

 

Edited By David Mellor on 18/11/2018 14:34:33

supertigrefan18/11/2018 14:12:20
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Posted by Don Fry on 18/11/2018 12:54:11:

A thunder flash is a grown up banger. Argue until you are happy, but trying to contain a fire in a sealed box not certified or designed to contain pressure is a very bad idea. The idea is to contain the fire while you take steps, in the opposite direction, at speed.

An ammo box and it's seal is designed to keep the rain out, and be tough enough to protect the contents from damage.

A couple of points:

To think of a Thunderflash as a grown up banger shows no appreciation of the energy produced by one.

I'm not "arguing" anything, I am presenting some considerations to make when selecting a suitable container. Each of us has different priorities to suit the environment, manner and way we transport our batteries, no single solution will meet of the concerns so a mixture of bag, safe and Ammo box would be the ideal.

So what is the design spec and certification of the ammunition containers being discussed? They extend to more than just keeping rain out and keeping the contents undamaged.

Seal it, vent it, keep it in a concrete bunker or do all three for all I care........do what you think is best, just consider what it is you feel you need to minimise. Like I said, the choice is your own.

supertigrefan18/11/2018 14:35:10
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David,

Yes an Ammo box is designed to keep bad stuff out but they are also designed to keep bad stuff in, that video you posted shows that firstly, you have to go some to start a battery fire and secondly, that a decomposing LiPO is much the same as a smoke bomb which a sealed Ammo box is more than capable of dealing with. What you're not considering is that the battery fire is a steady build up of pressure which will be released past the seal when it becomes critcal, the Thunderflash is an almost instant build up of pressure which distorts the box before the seal is able to release. The bottom line is that if you feel that a vented box is safe then vent it but if you're happy that a sealed box is not dangerous then seal it. I can't see what the issue is.

Edited By supertigrefan on 18/11/2018 14:37:25

Edited By supertigrefan on 18/11/2018 14:40:29

David Mellor18/11/2018 14:52:56
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I don't think there is an issue, just a bit of discussion.

As you say, each person decides what they think works best for them, based on what their understanding is.

For me, a good approach would be to use a regular ammo box with a seal to keep rain out, but have a couple of holes drilled at either end to vent any gas (and some heat).  A piece of duck tape over each hole would keep rain out, but pop off if the pressure built up in the box.

 

 

One thing that hasn't been mentioned is the probability of an "event" happening in the first place.

 

It seems to me that there may be a correlation between the physical condition the battery is in and its likelihood of "eventing" in storage.

 

Well maintained, properly cared-for and regularly checked (with a meter) batteries don't seem to "event" spontaneously in storage provided they are allowed to rest for 60 minutes beforehand.  It takes that long for the internal chemistry to equilibrate in response to internal temperature changes arising from discharging or charging.  Once that "golden hour" has passed, the chance of an event occurring in subsequent storage is essentially zero.

 

Most "events" - in fact all the events that I can find evidence of - occur within 60 minutes of either being charged or being used in the model.  Those events that don't fit this pattern seem to involve movement (such as as transport).  I can't find any examples of lipo "events" occurring to batteries that have been rested, checked then stored.

 

I think that the main concern it is over those batteries that have not been well looked after, are "puffed up" or have been previously damaged, dropped, impacted or abused in some way.  This can, of course, include brand new batteries out of the box, if they have been shipped with out-of-range voltages, are badly balanced from the factory, have been bashed in transit or behave oddly during initial charge.   

 

Based on what I've read, essentially all lipo "events" happen within less than 60 minutes of being charged or drained., rather than during extended periods of storage.  This seems to be particularly relevant if pre-existing damage has been caused but has gone unnoticed, or has been ignored, prior to use or re-charge.

 

Using a meter to check the physical condition of individual cell voltages and balance helps when identifying batteries at risk of "events" within that timeframe.  They will pin-point damage internally that you can't see externally, and any "dodgy" batteries should be stored away from good ones before being disposed of.

 

Edited By David Mellor on 18/11/2018 15:18:46

Edited By David Mellor on 18/11/2018 15:23:20

conrad taggart18/11/2018 21:07:27
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Ammo boxes and their various options shown here

https://www.youtube.com/watch?v=CnNId0mDnBo

C

Don Fry18/11/2018 21:15:59
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I have mulled over a response, or even thought why bother, but I have a major concern. There are beginners reading this, and misinformation on a public forum can cause serious grief.

I have a degree in Chemistry. In ancient times I was employed as a research chemist, employed by ICI, for a time, in the development of novel plastic explosives, for military use. I was briefed and trained in the storage and use of this stuff.

An ammunition box is, in this case, a NATO pattern box with a rubber seal. The basic design comes from America, and is a waterproof box what keeps bullets clean. American weapons are light, accurate, (expensive, delicate) and need good clean ammunition. Hence the rubber seal. Russian boxes are sealed sardine tins. Other nations use waxed/tarred cardboard, and nowadays, plastic. There is no intention to contain the content when burning starts. Why bother, a bit of galvanised tinplate ain't going to stop much. If you doubt me, look in Wikipedia. I checked today.

You have stated, in a gassing fire, the seal will release pressure. I would invite you to provide your measured source for this assertion. It was designed to be a moisture seal, and any other functionality is, I maintain, coincidental.

To keep lipo batteries in a sealed box without a proper vent is dangerous.

Furthermore, you have asserted that a thunderflash is contained when it goes off in a sealed ammo box. Now I admire your reflexes, light it, seal the box, scamper off, all in the five second fuse. ( and I have checked, it's the same 5 seconds today as it was in 1971). But, if it made a mark on your memory, and that seal did not vent pressure. The box bulged. Ring a bell?

And a thunderflash, is still a big banger, cardboard, 3 gram load, (and again, I have checked today, same as they ever were) and the same safety sheet I read today, says don't hold it when it goes off, you will get burnt. No mention of missing bits. That's a banger, and it bulged the box.

I repeat, to keep lipo batteries in a non vented box is dangerous. If your box explodes, as you say is your choice, but at least, just before your head restraint goes through your head, so will the thought, I told you.

Sorry about, the larger type, typed offline, and don't know how to re-size.

supertigrefan18/11/2018 22:42:27
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I hope you feel better now Don.

I wasn't going to respond either but rather than trawl the bible of Wiki for evidence I'll just fire from the hip.

I'm not posting to score points off anyone, I'm posting to put a different angle on the subject in response to a reply that was posted earlier just as I would hope to see\ hear when I post a question so that I can weigh up all opinions to come to a decision. You question my experience and reasoning.........crack on mate, I really couldn't give a monkeys', I've got nothing to prove to you, you're obviously very knowledgeable, intelligent and highly experienced in this area, it doesn't change the fact that a burning Lithium ion battery doesn't explode, it smoulders to a degree that just about any heavy duty container could deal with, even a pre-pubescent banger has more explosive force than a rapidly decomposing lithium ion battery.

One last thing: Wiki is a useful starting point but as you would know through your sourcing and referencing for your degree studies it is full of inaccuracies and unconfirmed sources, anybody can contribute and amend information on it. As a Bachelor in Chemistry I'm sure you are aware of that? Try finding the MOD spec and certification whilst you're there.....as the saying goes, if it's on Wiki, it must be true. Good luck. wink

Edited By supertigrefan on 18/11/2018 22:44:54

Edited By supertigrefan on 18/11/2018 22:46:55

Edited By supertigrefan on 18/11/2018 22:55:09

leccyflyer18/11/2018 23:19:34
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Skip to 6:09 and ignore the annoying antics of the fellers doing the test. The important thing to watch is the intensity of the venting with flames event. A little bit more than a gentle smoulder.

https://youtu.be/0nrsoMsEMNU
supertigrefan18/11/2018 23:33:06
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Who said "gentle" smouldering?

I've watched it and I stand by my statement that "just about any heavy duty container can handle that" if you feel that it couldn't then by all means exercise your right to vent your container, this is just going round in circles.

leccyflyer18/11/2018 23:53:47
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I personally know three people who have had lipo fires. One was lucky and got away with nothing worse than a slightly singed worktop. Another lost a bag full of batteries, but was able to throw the burning package out of the door.

The third one wasn't so lucky. He lost his entire garage, all his models and gear - fortunately his family were not harmed. Some years later he's rebuilt and continues tou use lipos - but you can bet that he takes the appropriate precautions now.

So you'll forgive me when folks who are clearly well informed on the topic and who take appropriate precautions are being told that they are wrong by someone who doesn't actually have any experience, or for that matter doesn't even use lipos and I point out that they are mistaken. Like a number of experienced users have pointed out, keeping, or worse still, charging, lipos in a sealed container is dangerous.

Stearman6519/11/2018 11:21:36
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My Ebay ammo box arrived this morning, well packed, bit dusty & sandy? Lid stiff to open, but very substantial. Rubber seal in lid, which I will remove, bargain at £9.50 inc' post.wink

**LINK**

a1.jpg

a2.jpg

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a4.jpg

Edited By Stearman65 on 19/11/2018 11:22:59

supertigrefan19/11/2018 17:37:17
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Posted by leccyflyer on 18/11/2018 23:53:47:

So you'll forgive me when folks who are clearly well informed on the topic and who take appropriate precautions are being told that they are wrong by someone who doesn't actually have any experience, or for that matter doesn't even use lipos and I point out that they are mistaken. Like a number of experienced users have pointed out, keeping, or worse still, charging, lipos in a sealed container is dangerous.

Who is saying they are wrong? Who mentioned charging LiPO's sealed? Definitely not me, you are making a lot of assumptions.

supertigrefan19/11/2018 17:40:53
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Posted by Stearman65 on 19/11/2018 11:21:36:

My Ebay ammo box arrived this morning, well packed, bit dusty & sandy? Lid stiff to open, but very substantial. Rubber seal in lid, which I will remove, bargain at £9.50 inc' post.wink

**LINK**

a1.jpg

a2.jpg

a3.jpg

a4.jpg

Edited By Stearman65 on 19/11/2018 11:22:59

That's a later, modified box, heavy isn't it.....not exactly galvanised tin plate.

Removing the seal will be lot easier than drilling it and will not turn it into a lithium blow torch.

Pete B - Moderator19/11/2018 18:34:34
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In a former existence, I was involved in the explosives world and partook of a number of demos of the effects of explosives for those who might not be aware of the dangers.

Using a typical 7.62mm type box, a detonator confined inside would seriously deform the box - a thunderflash usually launched the box to somewhere about 60 feet overhead. I'd be inclined to drill a couple of holes....

Pete

ken anderson.21/11/2018 10:01:04
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I've now joined the ammo box lads, this arrived this morning, its on the to do list(drill a couple of holes in it)

ammo box

ken anderson...ne...1..to do dept.

Stearman6521/11/2018 10:05:06
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Posted by ken anderson. on 21/11/2018 10:01:04:

I've now joined the ammo box lads, this arrived this morning, its on the to do list(drill a couple of holes in it)

ammo box

ken anderson...ne...1..to do dept.

Hi Ken why not just remove the gasket, drilling a hole could let rain water in if it's left in the open air.?

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