Anyone thinking Lipo is safe needs to think again

Sorry LFP et al, but this stuff simply isn't ready for prime time. This is (was) a 4s5ah 20C hard pack charged only to 16.2V (4.05v/cell) and set aside...never used. It only saw a few degrees C change in temp daily for the few weeks it sat there, and no direct sunlight, so I'm at a loss as to the cause. I'm just very lucky that it didn't spread to the other packs only inches away, and that the single pack didn't get hot enough to ignite the formica/particle board desk it sat on, or we would have surely lost our guest house that I use for ebike stuff and my office. Most of all, thank goodness it wasn't already mounted on a bike. People can evacuate, but a defenseless ebike can't escape a fire without its rider.

OMG John!

I've never heard of that happening. Some crazy impurity mfg defect in the cell?

I'm so sorry John! I'm glad it didn't burn your awesome guest house down.

What brand?
Life history?

More details, please.

I had a turnigy lipo go puffy on me once, at nominal voltage. No cycles on it, just bought it from HK 3 months ago and let it be.
Cut the bad cell out, and left it outside in the cold. It, slowly over time, expelled some magic smoke and then deflated. it has just sat there since, lookin' all soggy.

WTF???
Is is possibly john that the gauge that tells you its charged was reading low and you overcharged it with out knowing????

Arlo1 said:

WTF???
Is is possibly john that the gauge that tells you its charged was reading low and you overcharged it with out knowing????

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Hey Arlo... Are they these pack you attempt to buy on HK at 0.29$ per wh??

Doctorbass said:

Arlo1 said:

WTF???
Is is possibly john that the gauge that tells you its charged was reading low and you overcharged it with out knowing????

Click to expand...

Hey Arlo... Are they these pack you attempt to buy on HK at 0.29$ per wh??

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Yes, and the exact same pack I have 64 of... in various flammable places....

This could just be an annomally when some worker pushed the plastic covers together a little too roughly, and shorted a wire.

I worked in an engine rebuild place for 5 years, and one operator said they had a Caterpillar engine that blew-up after a few munutes operating, and it was brand new.

Glad nothing burnt, but might be explained once we invsetigate it.

liveforphysics said:

Doctorbass said:

Arlo1 said:

WTF???
Is is possibly john that the gauge that tells you its charged was reading low and you overcharged it with out knowing????

Click to expand...

Hey Arlo... Are they these pack you attempt to buy on HK at 0.29$ per wh??

Click to expand...

Yes, and the exact same pack I have 64 of... in various flammable places....

Click to expand...

Could it be the reason why they offer them at low price :lol: ...


they normally call that FIRE sale !!! :x

is that what we should call C grade cells

Doc

Doctorbass said:

Could it be the reason why they offer them at low price :lol: ...

they normally call that FIRE sale !!! :x

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Oh doc, you so punny

Anyway the hardcase seems like a bad idea IMHO.. can't tell if a cell is puffing or not! probably an odd dud with an internal short.. or bad wiring..

Shouldn't that be F grade for ..... FIRE!

I read this thread, then two minutes later got an email saying "The HobbyKing warehouse is exploding......"

John, did I read that right? The pack wasn't being charged or discharged at the time; it was just sat there disconnected from anything.

Nick

Tiberius said:

I read this thread, then two minutes later got an email saying "The HobbyKing warehouse is exploding......"

Nick

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Lol, I got that email too.

While I was at the factory and warehouse, I asked how many packs they had just explode/burn on the shelf. He said, "zero". I asked some workers and managers how many times they had seen packs burn/explode, they all said "zero" as well.

But, oddly, now that I think about it and look back through the pics, the hardcase packs were not seen anywhere at the factory I was at. Every brand/type (for so so many different RC brands), but no hardcases... I wonder if they farm them out to a different factory, and that's why they are so cheap.

liveforphysics said:

OMG John!

I've never heard of that happening. Some crazy impurity mfg defect in the cell?

I'm so sorry John! I'm glad it didn't burn your awesome guest house down.

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Nothing to be sorry about, I pretty much expected to lose at least a pack or two out of that group, and no real harm was done. I just never expected it while it just sat there.

Netronix,
I've got 15 of the Turnigy 20C hardpacks, 4s5ah. I've had them a little over a month, and all I did was bulk charge them 5 packs in series at a time to 81V with my ebike charger that I use for my 20s Konion packs. A day or 2 later I checked each pack for balance at the cell level, and all packs were fine at 4.04v to 4.06v per cell. That all took place in the first few days, and after everything seemed fine a week or so later, and I took them off the ceramic tile floor and put them on the desk where they sat out of the way, unused and untouched for several weeks since. It's rained a few times in the past week, so the humidity has changed a bit, but there definitely aren't any leaks in that room, so they didn't get wet. The only other change has been the daily change in temp, and it's been cooler than when Luke was down last year, so the range has been pretty typical with lows about 21°C (70°F) and highs of 26 or 27° (81F)

Tiberius said:

I read this thread, then two minutes later got an email saying "The HobbyKing warehouse is exploding......"

Click to expand...

I hope that's just a bad joke someone is playing.

John, did I read that right? The pack wasn't being charged or discharged at the time; it was just sat there disconnected from anything.

Nick

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The pack was just sitting there undisturbed, and not connected to anything.

Hm, OK.

Yeah i think you just had a freak accident like my Turnigy 20C pack. Luckily i caught it before i started using it. That happened to one pack out of 9. The other 8 are perfect, stay extremely well balanced too.

Not exactly confidence inspiring though.

I suppose it's hard for hobbyking to know whether or not a cell will fail like that months down the road. I wonder if the materials in these cells suffer of occasional impurities. Aside from the foil folding procedure, it's my understanding that these cells are generally made by machine.

I bet you your other packs will be just fine.
I won't advocate people buying these though. The lack of visual indicator that a cell is puffing makes these even more dangerous than normal lipo in my opinion.

This is such a coincidence, because I was just about to post a thread asking people to give real life examples of explosions/fires of Lipo that weren't caused intentionally.

The reason I was going to post it, was because until Lyen had his recent Lipo fire, I had actually not been aware of any member on this forum having a Lipo fire (excluding intentionally caused ones, or caused by things like use in an RC application, or puncturing the pack intentionally or trying to vent cells etc..).

As far as threads/posts I have read on this forum, there has been Lyen (who was using cheap Chinese Lipo, so I actually would discount that one), there was a guy once who said he was using a single parralel line of packs on a massively overpowered outboard motor on his boat, and he said the packs caught fire, but apart from that, I have never actually read of someone having a lipo fire that wasn't caused intentionally. This is now added to that limited list.

So, now we have a thread with this title, can anyone provide data on first hand (or verified) examples of someone having a lipo fire (quality Lipo that is, starting with Zippy and Turnigy as the base line), EXCLUDING, the following:
-Cheap Chinese Lipo
-Intentional abuse/destruction
-Massive over discharge or massive overbulk charge
-Radio Control applications

Maybe this should be a different thread, but the reason I am curious for people to start actually giving real life examples like John's, is that there is so much talk on this forum which reminds me of the hysteria with which people discuss drugs, ie "I once knew a guy, who smoked a doobie, and a month later he was selling his arse in the park for foils of crack, so that's what happens if you smoke weed", equates to "You need to shroud your lipo in a thick shell of steel on your bike, and charge in a concrete bunker, or you are a suicide bomber hell bent on death".

The fearful talk of lipo on this forum is what put me off lipo for so long, I felt like if I brought Lipo into my house I may as well start cooking meth in the kitchen for the danger I was putting my kids in.

But now John gets a brick of lipo to spontaneously combust on a shelf and it is like finding one of my bong buddies downtown in fishnets, and I am starting to take a hard look at my smoking habits

So can anyone chime in with more real life horror stories subject to the conditions above? Or is this the exception that proves the rule? And can I go back to my self deluded comfort? Afterall, I am a very good liar, and I am very gullible.....

The cells in the hard packs aren't loose at all, so I'd think any puffing cells would be even more visible since the pack would have to pop open to puff. This pack certainly did, and the puffing of that top cell is about as obvious as it gets.

Philistine,

On the bright side, I didn't see the actual event, and though it looks pretty black I don't think it actually caught fire, because that would have certainly spread to the adjacent packs that were within 1" either side of this one. Plus there's hardly a mark on the formica on the desk. I'm not even sure the bottom cell of that pack is toast.

That's very very wierd. The only logical thing I can think of causing it would be some kind of short, somehow the bullets contacting a mild conductor, that eventually overdischarged the pack.

Any chance of that? like a flaw in the plug covers?

I'm starting to think about where I can stash lipo I'm not using at the moment. Maybe I need an ouside lipo locker for the packs I'm storing till the next race. They are all on a fireplace hearth now, but it's crowded.

dogman said:

That's very very wierd. The only logical thing I can think of causing it would be some kind of short, somehow the bullets contacting a mild conductor, that eventually overdischarged the pack.

Any chance of that? like a flaw in the plug covers?

I'm starting to think about where I can stash lipo I'm not using at the moment. Maybe I need an ouside lipo locker for the packs I'm storing till the next race. They are all on a fireplace hearth now, but it's crowded.

Click to expand...

I'll try to do some forensics later today. I split the +/- on the connectors for easy series connections, but I inspected each of those as I went. There's no chance of a short at any of the connector ends, since all the connector ends including the balance taps were undisturbed even after the event. One of the mains was burned completely off at the pack end, so it's possible there was a short there.

A short as the actual cause seems remote to me though, unless some chemical/humidity/temp diff caused some slight puffing of a cell and the puffing created the fatal short.

I'm starting to think about where I can stash lipo I'm not using at the moment. Maybe I need an ouside lipo locker for the packs I'm storing till the next race. They are all on a fireplace hearth now, but it's crowded.

Click to expand...

That's a great idea. I'm going to store moth balled batteries in my fire place. I don't use it anyways.

Also, investigating fireproofing permanently mounted battery packs might be a good idea too....

Not because I think lipo or any battery properly treated is unsafe, but because in a long enough time span accidents and irregularities happen.

auraslip said:

I'm starting to think about where I can stash lipo I'm not using at the moment. Maybe I need an ouside lipo locker for the packs I'm storing till the next race. They are all on a fireplace hearth now, but it's crowded.

Click to expand...

That's a great idea. I'm going to store moth balled batteries in my fire place. I don't use it anyways.

Also, investigating fireproofing permanently mounted battery packs might be a good idea too....

Not because I think lipo or any battery properly treated is unsafe, but because in a long enough time span accidents and irregularities happen.

Click to expand...

We wrap our lipo's in adhesive backed fiberglass tape. Might not prevent a battery from combusting, but it will mitigate the impact, as well as prevent it from damaging nearby batteries.

http://www.amazon.com/CS-Hyde-Temperature-Fiberglass-Silicone/dp/B000REJN4S/ref=sr_1_4?s=industrial&ie=UTF8&qid=1304170040&sr=1-4

Not exactly the same tape we use, as it comes in 4 foot rolls for us and uses a different kind of fiberglass, but we have performed some light testing on it and found it would hold it's integrity for ~15-30 seconds with a propane bottle torch (3,600 Degrees F) before it fails, and up to a few seconds resistance with a oxy-acetylene torch (~6,300 Degrees F).

O-OH . my blood actually ran cold when i read this post. Ive always thought lipo fires are caused by "human " error.......................Good heads up for ALL lipo users, i store my lipo all over the freaking place, and im giving it to as many friends as possible now , better check up on that!!!!!

mike

edit can we get some more pics of the area? any particulate matter that would indicate smoke or fire eminating from the area?
as most of my lipo is taped to more lipo, i would be concerned how much heat came out and how fast. ...

Yikes !!..

Any smoke damage ? lingering smells etc ?

Pictures of a disection would be apreciated, specially at the circuit board end.... if there is anything of it left.. :|

Glad to hear the damage was minimal man.. scary shit. *looks over shoulder at desk full of various battery projects among messy desktop items....

Another possibility is something small and hard getting dropped on the top cell before the case was closed.
It wouldn't need to be vary big. With the vibration of air travel etc it could probably damage the cell. Especially if the cell went a little puffy. raising the preasure on a point contact. maybe even thermal cycling could do it.

I wouldn't condemn all LiPo just yet. So far I would say incidences like this are far lower than the bad Li-ion sony cells that got into various laptops.