In practice, that’s another story. :nerd_face:
And what I do in practice may be identical to what you do, namely rely on primaries.
But that has entirely to do with the pragmatic reasons listed in the OP: energy loss, shortened lifetimes, and expense of Li-ion cells. (I didn’t list cold weather, because I don’t spend much time on Mauna Kea!)
Quite possibly. Most of the time i do carry lights and li-ion cells with me in my truck. I also carry half a dozen 10-cell power tool packs, a practice I’m unlikely to discontinue however I’m aware of the concern and during heat waves remove the lights and take precautions with the packs. I’m simply counciling prudence, awareness, and continued observation of reality.
Thanks, Hank, for doing the research.
The first link goes to a broad sweeping overview of safety specifications and the like, offering no insight as to quantifying the risks.
The second link talks about the affects of high temperatures on the storage capacities of cells. Again, nothing to sink one’s teeth into on the subject of this discussion.
The third link “Thermal runaway caused fire and explosion of lithium ion battery” is a lot more interesting. However, it raises more questions than it answers. Thermal runaway is a stated risk at 130-150 degrees centigrade. Standards call for batteries to pass heating tests of 130 degrees centigrade. Oven baking tests cited in the report were conducted at temperatures of 150 degrees centigrade.
a. What happens below 130 degrees C? Is it relatively safe and that’s why there’s no testing of lower temperatures?
b. What were the results of the oven baking tests conducted at 150 degrees C?
We don’t know. This report was based on culling other research reports. To find the answers, we would have to read the original reports.
So, it looks like you’re right, Hank.
It always boils down to the same thing…
Do ya feel lucky? Do ya?
UN and UL requires cells tested to have long term stability at 70-75C. Above that point long term exposure(2 days) leads to self heating and thermal runaway so it may be unlikely to happen since it’s hard to maintain that extreme overnight but we know there are plenty of fakes and poor quality cells around that might not pass that test. Good thing I already avoid close in parking at malls and 10k parking lots, you never know what’s in the next car over.
You did not answer MY questions. I’ve been following enough “discussions” where you were involved, here and on CPF, to know that any answer I post will be “deliberatley misunderstood”, not actually read, and any question not answered. It will be nothing but a waste of time.
Post any evidence for a cell “self-igniting” at a temperature that can be reached in a car, and we can start talking.
First, we state what temperature this should be. Of course you can drag in an example of a black car parked in the sahara in full sunlight with a black flashlight lying not in the glovebox, but under the windscreen. 80°C maybe? And we’re not talking about degradation or aging, but exploding or venting.
I haven’t seen enough evidence that the temperatures inside a vehicle during the hottest of summers can cause a realistic danger above and beyond the normal Li-ion dangers. I do believe that keeping cells in this environment and keeping them 100% charged will degrade a cell quicker over time but from my observations, I have decided to ignore. My biggest concern is over discharge.
I also do not recommend, to anyone I come in contact with, the use of Li-ions. Although if asked, I will give my opinion. I usually mention pipe bombs and overstate how dangerous they can be.
Wash hands after handling doorknobs?
That depends on where the doorknob is!
Understanding risk? You need to know details about construction, materials, and handling.
Badly made li-ion cells are readily available, and fake wrappers to disguises crap as good ones are cheap too.
I don’t advise other_people to be lucky. How would they follow that advice?
You may feel lucky, that’s your business.
Hey, store it in the glovebox and just don’t drive the car, that will avoid a whole different hazard: vibration:
http://www.sciencedirect.com/science/article/pii/S0378775315007648
Always be lucky, if you know how.
Hmmmm. Now, how would one try to have better luck?
They say good judgment comes from experience, and experience comes from bad judgment.
Or, you can study statistics and epidemiology and try to change your odds even for things you haven’t personally seen happen yet.
Hey, the Europeans have a regular conference on fires in vehicles. Perhaps they should be consulted on this?
I’m way past done on this thread.
Hank,
I started this thread asking for people’s opinions on the subject.
I was particularly interested in people sharing any experiences that they may have encountered or otherwise knew of.
I think anyone that has read this thread from start to finish has gained a better appreciation of the range of opinions about the risks.
Thank you!
I’m going to stay away from them the same reason I stay away from ultrafires. However, such batteries are used in Tesla, and they’ve proven to be remarkable vehicles without a disclaimer for ‘do not drive or park in hot places’.
What I notice most so far is that most people are solid with their opinions and have a basis for them which they believe is adequate to justify their actions. What I next notice is a lack of actual evidence of a case of major damage to a car which could be reasonably be believed to have been caused by a LIon and heat. Nothing even close to that. There’s too much of this happening right now for there to not be one reasonably believable case discovered by now.
If this were a legal case in the US under trial, you’d have to prove the damage beyond a reasonable doubt to win- a standard which most of us believe is good and fair. The possibility of damage isn’t enough to carry that case or a jury hearing it. Show your proof if you have it, and don’t argue that there is none on either side if you can’t, because with all the LIon power tools my career-cohorts and I carry there would surely have been at least a few fires by now, yet I’ve heard of none. With so many roughnecks and unenlightened hooligans doing this with apparent safety, then you cannot successfully argue that it is unsafe for us more careful ones without some proof which has at least equal validity in the eyes of a reasonable person. It is not that there is no danger- only a fool would posit that. It is not where the line between safe and unsafe is or how close you’re getting to it. It is certainly not going to apply to those dealing with extremes of heat or poorly made cells. It is only about whether this is safe for most of us. Which I think it is but I also think it’s getting close to that line where safety is lost. How close I can’t say- . Some of us are comfortable here and some are not, that’s all.
I don’t feel lucky, but I do feel safe and if I’m not then please educate me with proof and not preaching so that I can actually be as relatively safe as I feel I am now.
Phil
Samsung phones with Li-Ion have exploded, Samsung 'attempts to silence report of Galaxy S4 catching fire' after angry customer uploads Youtube video | Daily Mail Online
But I have not seen any cases in which one explodes in a flashlight, causing more damage, and destroying a car or killing a person. I also believe the issue is overblown, but I wouldn’t want to store flashlights in a state that they can be damaged because I am too lazy to take it out of a hot car. I don’t think it will hurt me, but it will damage the cell and perhaps make the flashlight unusable, while the items you describe are modular, and the cells are located outside the actual device.
Maybe a lot of people are mistaking caring for their items as worrying their own safety. I don’t think it will hurt me, but it will hurt the cell.
Sawmaster:
FYI, a civil case would be decided by a preponderence of evidence.
Notwithstanding that technicality, your other points are well taken. 
Further on down the article:
“In a separate incident, an Irish Samsung S3 owner claimed his handset burst into flames as he was driving his car. However, it was later discovered, following tests by the Fire Investigations UK (FIUK) team, that the phone had been previously placed in the microwave to remove water damage and this may have been the cause of the fire.”
OMG, can you imagine the snap-crackle-and-pop that was going on while the phone was being microwaved? 
:_( :Sp
. . . . .
Okay, let’s add that to our safety guidelines: When drying out any Li-ion cells, do NOT microwave them.
:evil:
You’re ignoring 4 different cases in which batteries have exploded without any warning.
Do you really want me to go over the details of the other cases and why they don’t apply to this discussion?
Yes. Like I said a lot of people are likely mistaking caring for their items as worrying their own safety. I don’t think they’re dangerous, but people like to take care of their products.
People can read your article and make up their own minds.
So you can’t really explain why they don’t apply?
I’m not out to convince anyone about the details. 0:)
Then I have no idea why you said this:
unless you just wanted to nitpick one poor case, and then retract it when you realized that it does apply, and degrading batteries are indeed dangerous.