There are some theads about car flashlights, but I think this topic is not very well covered.
First of all what you can image. I’m looking for a flashlight to be in a small emergency pouch in the car. May be there for eons without being used.
I think there are many that look pretty good, the most common concern being that the baterries will be left in the car for a long time. I think something like the Convoy T4 our similar would be fine.
=> My real concern
Summer is coming and I live in the east of Spain. Here summers are nothing like (I dunno) in Arizona or something like that, but we can get up to 42 degrees Celsius (worse case, we don’t use to get to 40) and the car can get pretty toasty in the sun.
Do you think the flashlight and the batteries will be ok in those conditions?
Would AA be better than Li-Ion batteries like 14650 if they are going to be in the heat?
The car has to be in the sun BTW, no way to avoid it and all cars do arroud here.
I was thinking if throwing in the car a Boruit V3 I have too, but this concern about the heat and the battery is making me rethink it.
If you don’t mind cracking open the windows, there are visors/guards that mount on the outside right above the windows which can shield from rain. Also, those old school windshield reflectors/thermal blockers can help lower the temperature in your car, and they come in all cool colors and designs now.
Also, use lithium primaries, they’re reported to take up to 60C.
I chose the Skilhunt H150 for my car because it can use AA Eneloop and AA ultimate Lithium (not rechargeable).
It also works with 14500 LiIon, so i keep all 3 battery types in the car kit during winter, and they all still work in Spring.
In summer the LiIon seems to get drained by the heat, so I dont keep it in the car for that half of the year.
Eneloop holds charge better in summer car heat. The floor of the cargo area of my white station wagon, parked in full sun, as well as the glovebox, gets to about 110F. The inside ceiling can get to 135F.
AA ultimate Lithium has the longest storage life and tolerates heat best, but they are more expensive to use than rechargeable Eneloop.
I rotate my rechageable batteries with freshly recharged ones, twice a year, on April 1 and Oct 1. Winter temps are about 10F, summer temps about 95F.
40°C in the shadows means 60+++ in the sun and this is rapidly approaching “unsafe” territory for LiIons. At the very least you’ll have to expect them losing capacity permanently + rapidly, esp. when they are at (or close to) 100% charge.
I started keeping many 18650 based lights in the vehicles back in 2016. I used to check the batteries every 6 months. In recent years some of them get checked approximately every 2 years. Whether the lights and batteries are in the vehicles or in the house it’s not good to store batteries fully charged. So they’re typically at 4.0 volts in the vehicles.
You never know what or how long the “emergency” will last. If you have to leave the vehicle or look down a dark road with no lights 100m or more you’ll be glad you have an 18650 sized light or two.
If your idea of an emergency is having to look under the seat then yeah go ahead stick with aa.
Most high performance liion cells are rated to 80C max temperature these days, but storing cells at elevated temperatures and at full charge will shorten their lifespan and capacity faster. Keeping them at <4.1V will help to improve the situation.
NiMH cells can offgas when subjected to high heat or high discharge rates, ballooning the switch boot of the flashlight. Poking the boot with a needle would probably prevent that from being an issue.
I’ve kept AA/AAA Li primary cells in flashlights in cars for years in Texas . Also not Arizona, but consistently much hotter than Europe. No issues whatsoever.
I function check these lights ~annually but otherwise never use them - they’re for emergencies in any situation where I don’t happen to have my work backpack or luggage, which sport a flashlight or several as a matter of course.
Correct, an insulated lunch bag or such and under the seat, it is the coolest place and be careful about under the driver’s seat because a sudden braking can cause things to go under the pedals.
For lights and radios that never get used but that I want for emergencies I keep the batteries separate, it makes it easier to grab them for annual recharging and switching out.
My thinking is that if circumstances have me fumbling for a light in the glove compartment or a bag - probably in the dark - I don’t want the process to be any more involved than tightening the tailcap to unlock. Emergency radio, on the other hand, remains in its sealed packaging since that’s going to be a more considered activation process.
I personally feel a bit more comfortable with NiMH (Eneloops) for something rarely used and stored inside a hot car. But for long runtime and temporary max brightness I wish there were more current options in this category:
I’m in Australia and we can get temps up to 45 C . One car is outside 24/7 and used to have a dash cam with a lithium pouch cell in it. I discovered the pouch battery was rather rotund and not very healthy. So I wouldn’t store lithium ion batteries in a car, make do with alkaline or NiMh. At least you know they can’t cause much damage (well, apart from alkalines leaking!)
Might not be the answer anyone’s looking for, but I don’t carry any lights in the car at all. Too easy to be forgotten about, not even the “once yearly check-up / maintenance” that people crow about.
I just always carry a light in my pocket or bag, and those lights are used regularly and are always charged. No unfortunate “surprises” once you need it and find that it’s dead.
To me, it’s just easier to carry 1-2 lights that are always maintained, than to try to squirrel away dozens of shtf lights and try to maintain them… or even remember where all of them are hidden.
Has there ever been a thread where somebody had a problem with a lithium ion battery in a flashlight in a car here? We are not talking about pouch cells.
For those that are worried about it I would suggest you read through all of the comments made by mooch in this thread that I’m going to link.
It wasn’t a flashlight, but I had a Li-ion jump starter in my car fail. It has been in there for a few years and indicated it was at 100% charge last fall. But not when I needed it during the winter, the voltage had dropped to 4. Fortunately I bought it at Costco and got my money back. And more fortunately, I had a set of jumper cables I could use to start the other car. The one I had was replaced with something like this:
A jump starter is a whole different kettle of fishies and variables.
Edit,
Most/all? of them are using pouch batteries with four in series to get up to 16 plus volts. Many of the older ones only used three batteries in series to get up just over 12 volts. Maybe some of the cheaper ones still use three batteries??
I’ve had three different ones. The one I currently have goes to 16.35V at 100%. I store it in the vehicle at 96% which is more like 16.05V.
The first one I had would shut off at about 16.0V.
I don’t know if the manufacturer intentionally set the cutoff point low. That one just had four bars to show the battery status. I stored it at about 15.6V. I gave that one away to someone that needed it.
I don’t remember the numbers on the one that’s in my wife’s vehicle but they are written down on the device and again I store it a little bit under 100%.
The question is more about a single cylindrical lithium ion cell in a flashlight subjected to 55 or 60C heat whether it’s in a vehicle or elsewhere and any problems.
I’ve found it prudent to bring my noco jumper inside if I plan to be away from my vehicle for longer than 8 hours, or to (as others have mentioned) put it in a well-sealed thermally insulated bag or box. Otherwise, I generally don’t leave any lights I care about in the car. Tiny AAA lights ftw?