Overblown Concerns Over Li-ion Batteries Stored in Cars

Normal midday temperature is about 32-35 Celsius (up to 95 Fahrenheit) in the open over here in Malaysia, and sometimes it can hit up to 37-38 Celsius.
But bear in mind that this kind of temperature is throughout the year.

I’ve keep flashlight using 2x CR123 batteries inside my glovebox ever since I own my 1st car back in 2004, from Surefire E2e, Pelican M6 LED and now Fenix P3D without any problem. I also have a pair of new CR123 as spare in the glovebox too.
Recently this year I used to keep Jetbeam C8 powered by 18650 cell, with rechargeable USB but revert to the Fenix as the USB cable that comes with the Jetbeam started to deform when left inside the car.

That sounds plenty hot enough to to heat up the interior of a parked car. Park in the sun, and roll up the windows. You might not be cooking bacon, but you could still fry your buns.

My own choice mirrors yours. I would use lithium primaries.

The thing for me is that my car light is just an emergency light. I want to put it in my vehicle and forget about it. If I used Li-ion for the car light, I would want to carry that light with me when I parked on a hot, sunny day. That's a hassle I don't need.

We can argue this to no end and there will always be at least two camps involved. But the empirical evidence shows that within reason, LIon cells can be very safe and almost always are. Going from safe to unsafe can be a very long-distance jump which once begun might not be stoppable and that is worth considerable thought.

People learning to fly commercially are told that you start out with two bags; one is your luck and the second your experience. You can’t tell how much the first bag holds so you focus on filling the second one because if what you need is not in one of those bags when you need it, it’s all over for you. Don’t waste the first bag being stupid.

Above all don’t bash others who see things differently. Especially that.

Phil

Depends on the car and where the car is parked:
if you have a 100k$ car parked in a 700k$ house where you live with your whole family and a potential fire can destroy everything…it’s a bad idea

If you have a 500$ car parked on the other side of the street and you need a good flashlight in your car everyday, it’s another story.

As an emergency light which you actually never use, a flashlight with some lithium primaries or eneloops is the best bet. No risk and In case you need light you have a nice working light. That is why I have no 18650s in any car.

Actually your reasoning is completely backwards and shows classist misunderstanding bias: the people with the $100k car and $700k house have car insurance, good house insurance and good health insurance, whereas the guy with the $500 car has insufficient insurance for his house or family probably (if he has any) and would suffer more by such a fire :stuck_out_tongue:

But still, either extreme or anywhere in between, I would recommend against doing it. And using Lithium primaries is still better.

Don’t rely on the assumption that your car, home, and fire insurance are going to pay for losses.
Not that anyone would be intentionally careless because they’re insured — right?

If the insurer’s lawyers can argue you were careless, or used something wrong, or used non-brand-name equipment, you may not be covered for losses that they can attribute to lithium-ion batteries — remember this isn’t about what you did, it’s about what they can claim you might have done.

There is a LOT of expertise being dedicated to denying claims for fires attributed to lithium-ion problems.
Here’s a discussion of how the lawyer-them-away approach to claims is done, by lawyers who do that kind of work:

It always comes down to the same thing:

Do ya feel lucky? Do ya?

If an 18650 vents or even explodes due to heat in the car, this means that the car was already burning beforehand and the additional damage caused by the exploding cell is negligible.

And the guy measuring 1000°F (538°C) on the bezel of his flashlight should get himself a decent thermometer and some education how to use it.

Why don’t you think? What do you think instead?

I read what you posted in #22, though I don’t see how the linked FAA document relates to the topic of this thread. But according to that document, Litium metal primaries are a lot more dangerous than Lithium Ion rechargeables - in case they are set on fire, somehow.

Any decent 18650 can tolerate 80°C, it’s the usual temperature limit for high current discharge. 60°C even for extended periods (weeks) will age the cells, but is not dangerous. I.e., above 80°C (176°F) one could start being concerned about battery safety. 80°C in the glove box. Go figure.

80C is hot but not impossible to reach in the central/southwest and even if they don’t vent or fail catastrophically they will degrade. At that temperature, cell failure becomes more likely to cause a fire. Autos are made of combustible materials exclusive of the papers and whatnot also kept in glove boxes. Were talking about EDC’s left in the vehicle day in day out. This is all about risk assessment. There is risk, less for some, more for others, but saying there is no risk at all is wishful thinking. Some will get away with skirting the grey edge of caution and some will prefer not to. Even good cells can develop faults and bad cells come preloaded so eventually Murphy will have his carbeque.

The report provides the results of tests conducted under various conditions. However, I could find no documentation of any actual events. Moreover, while the test results were provided, the testing protocols were not discussed. So, we don’t know how the fires were started - all we know is the aftermath of the fires.

If the tests show that it can happen then sooner or later it probably will and might have already. Documentation might be hard to find since it would be hard to tell from the remaining slag pile whether cell rupture started the fire or happened during the fire. Also, to find it they would have to be looking for it, how often do carbeques get a forensic study before being sent to a scrap dealer. We’re not discussing legislation here but whether it not it’s advisable or whether the risk is overblown. It might be minimal but it’s not zero.

http://www.researchgate.net/profile/Qingsong_Wang4/publication/257224404_ChemInform_Abstract_Thermal_Runaway_Caused_Fire_and_Explosion_of_Lithium_Ion_Battery/links/54cf7bc10cf29ca810fe2f30.pdf

cited in http://www.researchgate.net/publication/229047548_Capacity_fade_of_Sony_18650_cells_cycled_at_elevated_temperatures_Part_II.\_Capacity_fade_analysis

see also http://www.ul.com/global/documents/newscience/whitepapers/firesafety/FS_Safety%20Issues%20for%20Lithium-Ion%20Batteries_10-12.pdf

These problems appear to suggest the cheap vaper equipment industry may need some attention.

Isn’t that the point of all this discussion? How minimal or real the risk is?

I mean the risk of you catching a serious disease from handling doorknobs might be substantially greater than the risk of a Li-ion fire, but that doesn’t mean that you wash your hands every time you open a door.

Or does it? :evil:

And as to the tests, what do they really prove unless we know what the test parameters were! I would be more inclined to be concerned if the test conditions were closer to, say, 150 degrees F, than if the test conditions were conducted at 300 degrees F. And I would be less inclined to give the report much credence if an external ignition source was used to propagate the combustions.

You got me. I haven’t the foggiest notion of why I brought up the FAA report to begin with. :wink:

I just think it unwise to give it an AOK thumbs up. Regardless of how complete our knowledge base or understanding of any tests or their outcomes people will read this and say “these guys said it’s fine so I’m gonna do it”. Blowing off test data or standardized recommendations for no better reason than you don’t agree with it is small reason to suggest someone else stick their neck in the noose. The risk may be small but how small? Plane crash, struck by lightning, random gun violence, heart attack? At what level of risk does one begin to take precautions? It’s an individual decision and there’s not enough data to be informed but it’s pretty easy to err on the cautious side for the time being. There are far more vapers than flashaholics so I have no doubt that failure mode testing of single cell high current devices exposed to excessive temperatures will be forthcoming.

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.