# Leaving flashlights with batteries in the car in the summer



## Advil (Mar 12, 2010)

Hey guys. I've been lurking around for a while and I've finally gotten a couple flashlights. I have a EDC bag that I keep a couple lights in, and a light in the glove box of my car. Texas summers get extremely hot and I'm worried about leaving my bag with lights and all in there during the day. I've been reading about batteries and I know that alkalines are definitely not an option. So I've been looking at non-rechargeable lithium (energizer) and Nimh (eneloops).

The energizer box says that they're very durable and can withstand up to 140ºF so that made me feel good about them being in the car, but I'd rather have rechargeables and was looking at replacing them with eneloops when the die. Will NiMh batteries survive this kind of heat? Will the flashlight even survive this?

I figure the lights themselves won't mind the heat since LED's get so hot anyway, I just don't want batteries exploding in my light/car/hand!

Thanks


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## Dioni (Mar 12, 2010)

Its a good question. I want to see the answers too!


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## OCD (Mar 12, 2010)

Peaked my interest!


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## JonN06 (Mar 12, 2010)

I'll jump in as an interested person that wants to know as well since i'm in oklahoma and currently have a single AA with alkalines chilling in the truck at this time. :laughing:


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## Flying Turtle (Mar 12, 2010)

I've got a couple old lights running alkalines in the car. Haven't had a problem yet, but I do check them maybe three times a month. Do that and make sure they aren't that old and I think it's okay. Lithium batteries, of course, are the ideal choice for hot or cold conditions.

Geoff


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## ampdude (Mar 13, 2010)

I always keep some primary lithium cells in the glovebox. I think if they're out of the sun, you should be okay.


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## Lynx_Arc (Mar 13, 2010)

typically I wouldn't leave expensive lights in a vehicle, a few cheap useful ones, occasionally taking better ones when you are going somewhere more than usual. I check my lights after each season, once in the spring and once in the fall as the drastic change in weather has ended. I recommend at least checking twice a year if you use alkaline batteries for both leakage and if the batteries are good. weak batteries should be removed immediately because when they are dead the chance of leakage increases tremendously IMO.


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## hoongern (Mar 13, 2010)

I am too in the search for good cells for the car. Do lithiums (i.e. CR123 or AAA Energizer Ultimate Lithiums) have a significantly shortened lifespan in hot conditions?

What I've been doing for now is using cheap alkalines, but I keep them out of the light in a separate small ziplock bag, so that if they leak, it won't damage the light. Of course, this requires extra time to use the light as you have to put in the cells first before turning it on, and taking them out when you're done.


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## don.gwapo (Mar 13, 2010)

Got two 2xD incans, 1xAA led using both alkaline in my car. I haven't encounter any problems of them since I put them in my car and it's been more than a year now. I checked them once a month for battery leakage but they still in good shape. Not to mention the car is always under the sun from work or house.


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## march.brown (Mar 13, 2010)

I keep a couple of torches in the car ... I have a Saiko SA-8 (Li-Ion 18650) in the glove compartment and a Zhongsheng (3AAA Hybrio LSD) in the door pocket ... They are checked about once a month or so and I will charge the cells as and when necessary ... I will probably charge them up about twice a year, maybe just before Winter and Summer.

If the car gets too warm then the self-discharge rate will increase, so I might have to consider charging twice in the Summer just to be certain.

I always have my EDC with me though, just in case.
.


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## Mr Happy (Mar 13, 2010)

The answer could be Eneloops. Take a look at this thread:

Eneloops Left In Car For 1 Year - Results


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## Dioni (Mar 13, 2010)

Mr Happy said:


> The answer could be Eneloops. Take a look at this thread:
> 
> Eneloops Left In Car For 1 Year - Results


 
Thanks for the link. Great infos there.


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## fizzwinkus (Mar 13, 2010)

I was curious if anyone had experience with cr123s (primaries) in a texas summer? i've got an m2sc4 in the glove compartment and have been thinking about that a lot lately.


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## Robin24k (Mar 14, 2010)

If the battery is going to be subjected to harsh conditions, I would go with lithium primary. There's no need to use NiMH when the light won't be used often and it will be stored for long periods of time. Assuming you have your EDC, the glovebox light shouldn't be used often, so the rechargeables won't be used to their full potential 

I would just check up on the voltage of the primaries every year or so to make sure they still have a charge, or maybe even swap them into your EDC and put a fresh set in the car.


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## march.brown (Jun 12, 2010)

*Keeping batteries in the car.*

Today , I did some measurements of the temperatures inside the car with a temperature in the shade of 69.8F (21C).

The car was left in the sun with all the windows closed for just over two hours with the sun shining on the black dashboard top.

The temperatures were taken with an infrared thermometer which I know is accurate to within a couple of degrees at 100C.

The dashboard top measured 149.0F (65C).
A glasses case in the top of the glove-box measured 124.5F (51.4C).
A torch (Trustfire F20) in the bottom of the glove-box measured 111.5F (44.2C)

Bear in mind that the outside air temperature in the shade was only 69.8F (21C) ... The interior heats up way beyond what I thought I would measure.

On a hot day , say in the eighties , who knows what the temperatures would be.

As it is , the bottom of the glove-box is already near the maximum temperature quoted for Lithium cells ... I might have to put a storage bin under one of the front seats to keep a torch in , unless someone has a better hiding place that would be cooler ... It would be preferable to have the torches ready to hand rather than being kept in with the spare wheel under the boot floor.
.


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## StarHalo (Jun 12, 2010)

*Re: Keeping batteries in the car.*



march.brown said:


> On a hot day , say in the eighties , who knows what the temperatures would be.



Near boiling: http://www.randomuseless.info/318ti/temperature/temperature.html

The popular myth is that the space under the seat is the coolest accessable area in the cabin, but I've never seen it measured.

And as always;* General rule of thumb - no rechargeables in extreme heat or cold.*


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## VidPro (Jun 13, 2010)

*Re: Keeping batteries in the car.*

yes why is that under the seat i always find is cooler. no direct sun hitting under the seat , there is a bunch of insulation (seat) between the sun heater and the underside of the seat, the other side (floor) is in the shade, and hot air rises (or stays up).

Cars in california in direct sun with windows closed are always to high (for batteries) , without making some changes. trunks are not cooler ever from what i have seen, glove boxes are to close to the sun heater above it, AND are also often effected by the cars Heater venting internally.

allowing air entry (at risk of some criminal seeing window down a crack) using REFLECTIVE sun shades , is best, stop the heater (sun) from getting in. i am easily leaving my lights with batteries in my car, because even in 100*+ temps my car is agressivly shaded with reflection and the windows can be down 1/4" just enough to allow convection air to move a bit. plus parking in the shade and happily walking.

link to things i am talking about 
http://www.toysrus.com/product/index.jsp?productId=3934861
roll down side window sun shaders , clip them on before leaving car, sometimes is impractical or illegal to use while driving.

http://www.amazon.com/dp/B0002JM79G/?tag=cpf0b6-20
like these things, not white stuff or logoed, full reflection, this style also is insulative too, and getting the Big ones (truck size) instead of ones that leave gaps everywhere.
using these things in both front and back.

links for the pictures , to get the idea. with this stuff you can also save wear and tear on your AC and Gas itself as you no longer have to run the ac so hard to get re-cooled again.
a Pound of Prevention and maintance is cheaper than any medicine


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## Black Rose (Jun 13, 2010)

*Re: Keeping batteries in the car.*



VidPro said:


> allowing air entry (at risk of some criminal seeing window down a crack) using REFLECTIVE sun shades , is best, stop the heater (sun) from getting in.


Depending on what you drive, vent visors for the side window(s) allow you to roll the windows down a bit and reduce the risk of criminal activity (also keeps rain out should it rain). 

My vehicle is parked in an open parking lot all day and the vent visors allow me to let the really hot air out of the car.

I keep a light (with Energizer L91 lithium cells) in the door pocket and some spare cells in the glove box.


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## march.brown (Jun 13, 2010)

*Re: Keeping batteries in the car.*

I might try putting a piece of white material on top of the dashboard when I leave it next time ... It should hopefully keep the glove-box cooler.

If you leave windows slightly down on some cars , the alarm system is triggered by the breeze.

Today was dull and wet , so I couldn't re-check my temperatures ... I was going to check under the front seat plus in the boot too ... It would mean putting the car out into the sun as it is usually in the shade of the house ... I will try again when the sun comes out next.
.


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## kingofwylietx (Jun 13, 2010)

*Re: Keeping batteries in the car.*

I wonder:

You can buy the reflective solar shield (such as you show for the windshield) in large sheets from a hardware store.

What result do you think we would see if you placed a sheet of it between the vehicle headliner & roof? Has anyone tried this to see if it helped reduce radiant heat from the roof of the car?


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## march.brown (Jun 13, 2010)

*Re: Keeping batteries in the car.*



kingofwylietx said:


> I wonder:
> 
> You can buy the reflective solar shield (such as you show for the windshield) in large sheets from a hardware store.
> 
> What result do you think we would see if you placed a sheet of it between the vehicle headliner & roof? Has anyone tried this to see if it helped reduce radiant heat from the roof of the car?


 I don't know if there is any insulating material between the roof and the headlining , but my headlining felt quite cool when I was doing my measurements ... Perhaps that is another temperature measurement to do next time.

I think the biggest culprit is the black dashboard and interior of the car which is heated up by the sun shining through the glass ... My dashboard was very hot even though the temperature in the shade (in my garden) was only 69.8F (21C).

Some of the dark glass , that is fitted to some cars , warms up a lot ... In the UK we are not allowed to have dark glass in the windscreen or front side windows ... Motor cyclists helmet visors have to be clear too.
.


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## march.brown (Jun 16, 2010)

*Re: Keeping batteries in the car.*

Latest temperature figures when the outside temperature in the shade was 71.2F ... This temperature is the air temperature in deep shade behind a wall and under trees.

The car was left facing the sun for about three hours.

Top of the Dashboard .................... 158.0F
Inside the top of the glovebox ........ 127.5F 
Inside the bottom of the glovebox ... 115.5F
Under the passenger seat ............... 101.5F
Temperature of the spare wheel ....... 86.5F
(spare is under the boot floor)
Headlining above the driver ............. 134.5F
Door pocket torch ........................... 94.0F
Surface of cloth seat ...................... 138.0F

Looks like the door pocket is OK though the sun may not have been on it long ... Under the boot floor in the spare wheel compartment is the coolest at only 86.5F ... Probably the best place to keep a torch and all the spare batteries.

Bear in mind that the shade temperature was only 71.2F here in the UK ... I wouldn't like to guess what these temperatures would be on a hot day.
.


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## mtngoat (Aug 8, 2014)

*Long term storage (car glove compartment) battery question*

Ok so I have a Fenix E35UE and im planning on useing it in my car, leave it in the glove compartment until I need it. 

My question is, is it better to store it with an 18650 battery in it or 2 CR123 Primaries?


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## Yamabushi (Aug 8, 2014)

*Re: Long term storage (car glove compartment) battery question*

Better to use CR123 primaries because of low self discharge characteristics and, if applicable in your locale, excellent tolerance of extreme temperatures.


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## whiteoakjoe (Aug 8, 2014)

*Re: Long term storage (car glove compartment) battery question*

All my (occasional use) lights are running AA or CR123 Lithium primaries.


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## reppans (Aug 8, 2014)

*Long term storage (car glove compartment) battery question*

Agree with lithium primaries for storage, but I would highly advise locking this light out mechanically (untwist a half turn) or store the batts out of the light when not in use. Perhaps I'm being overly cautious, but this is an electronic switch light with parasitic drain. One review here mentioned 5yrs to drain the batts, but I have lights in my cars for much longer than that, still on the same cells. Also, a reasonably common fault among electronic switches (for those that go bad) is accelerated parasitic drain. 

The extra precaution is due to the CR123s used in series... if these cell discharge somewhat unevenly (who knows how constant vibration and extreme heat/cold cycles affect individual cell), then you risk reverse charge and spectacular failure... as in explosion, fire, and toxic fumes.


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## WalkIntoTheLight (Aug 9, 2014)

*Re: Long term storage (car glove compartment) battery question*



reppans said:


> The extra precaution is due to the CR123s used in series... if these cell discharge somewhat unevenly (who knows how constant vibration and extreme heat/cold cycles affect individual cell), then you risk reverse charge and spectacular failure... as in explosion, fire, and toxic fumes.



I didn't realize that CR123 lithium primaries could catch fire if abused like that. Is that also the case with AA lithium primaries?


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## reppans (Aug 9, 2014)

*Re: Long term storage (car glove compartment) battery question*



WalkIntoTheLight said:


> I didn't realize that CR123 lithium primaries could catch fire if abused like that. Is that also the case with AA lithium primaries?



Have a look through the "Smoke and Fire..." sub-forum here. I don't follow it much, as I'm small single-cell AA/CRAA/14500 guy, but I've never heard of any examples of L91s venting with flame - it is a somewhat different chemistry (Li-iron vs Li-manganese) and the voltage is much lower, afterall. 

The experts say yes, it's possible, but no one can cite an example... but that could also just be due to it being a less common user config than 2xCR123 - (at least within the flashlight world). 

http://www.candlepowerforums.com/vb...fety-of-Lithium-Primary-AA-s&highlight=Safety


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## R.W.D. (Aug 15, 2014)

*Re: Long term storage (car glove compartment) battery question*

I use primaries in all my lights that sit around and I would say its the best choice. I have never had any probs with surefire cr123's no matter how savage I get on them and I do get harsh just to see how far I can go. Energizer lithium AA's and surefire cells are the only ones I will vouch for because I never use any other brand primary cells. They are safe to a point. 
You have to think if they weren't safe they wouldn't really sell them as much as they do right? 

After things I've done ill say the obvious, do NOT short lithium cells primary or rechargeable, do NOT smash them.., don't throw them in salt water don't wet them period, had one pop in a cheap light after I loaded the cells into it in the rain.. Don't discharge them rediculously fast which is a given their not made for that and can over heat and pop. I've never experienced them "catching fire" they explode.. I personally believe the fire risk is from other materials catching fire from either being combustable and the cells way over heat or most likely from them popping. And when they pop they almost always seem to just blow the whole head end off/+ end it's the weak spot. 

But seriously if you are leaving them laying around in a light there shouldn't be any safety problems at all. I buy old/vintage surefire lights NIB and I use the batteries that come with them until dead. Not sure how much of a deal that is but I've had no problems with it. 

Like said above if its an electronic switch lock it out so it doesn't drain batts without usage. I had my TK45 screw up and start acting funny they told me its from leaving batteries in it and in a way "aging" the circuit because power runs through it on or off if batteries in it. I'm no genius on light circuits though so that's for another person to emphasize.


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## kaichu dento (Aug 15, 2014)

*Re: Long term storage (car glove compartment) battery question*

One really important part of the equation is what part of the car the lights are left in. I've never had a problem with lights left under the seat or in the door pockets, but did have a blowout with one left in the dash compartment with the sun pounding on it a couple summers ago.


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## Norm (Aug 15, 2014)

*Re: Long term storage (car glove compartment) battery question*

Several similar threads Merged - Norm


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## reppans (Aug 15, 2014)

*Re: Long term storage (car glove compartment) battery question*



R.W.D. said:


> ....Like said above if its an electronic switch lock it out so it doesn't drain batts without usage. I had my TK45 screw up and start acting funny they told me its from leaving batteries in it and in a way "aging" the circuit because power runs through it on or off if batteries in it. I'm no genius on light circuits though so that's for another person to emphasize.



Interesting, especially coming from a manufacturer, and the first I've heard of this theory. But it does makes sense, and might explain why some dedicated manufacturers of e-switch lights choose shorter (than what seems to be industry standard) warranty periods.


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## R.W.D. (Aug 15, 2014)

*Re: Long term storage (car glove compartment) battery question*

That's the same I was thinking, about the warranties.


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