100+ degree weather & flashlights: best practices?

I always carry an "emergency kit" in my Jeep; various essentials including LED flashlight w/rechargeable NiMH batteries. Along with other "perishables," I keep the flashlight/batteries in small insulated cooler to mitigate effects of heat.

What else can I do to protect my in-car flashlight/batteries from the heat? Should I NOT keep the batteries in the flashlight when it's not in use? Should I consider changing to another type of light and/or batteries? Something that's less impacted by temperatures?

Appreciate any input.

Dan

Consider using lithiums. They will work better in the heat as well as cold.

Dan, the heat here in my new neck of the woods is tough,but nothing compared to the Arizona summer.I agree with MTFD17, begin keeping lithiums in your emergency lights. Also if you use the lithium batteries for even a short period of time,such as testing the lights,replace them. Once a lithium is used,it may begin a slow discharge cycle not totally unlike a alkaline battery. To test my emergency lights I always use batteries out of everyday use flashlights. I have no scientific data to back this up, other than the fact that at work several bits of our equipment use 123's for memory and data protection. It appears that the lithiums that are called into duty for even short periods of time do not last in their environment as long as unused lithiums. Again,no hard proof,just a general,perhaps somewhat vague, observation from several technicians and myself.

High heat tends to bring high humidity; avoid headlamps as they will reflect glare close to your eyes.

You might line the container with tin foil; it'll reflect the heat and slow down the rate at which the contents heat up.

Re: 100+ degree weather & flashlights: best practi

In the Summer, I keep water in my car in a thermos bottle. It stays cool for a couple days, and never gets hot. MUCH better than an insulated cooler. Maybe some vaccuum insulated food jars might be large enough for some of your lights, or atleast your batteries.

Of course, the goal here is to moderate the peak temperatures during daylight hours. I'm not sure how battery chemistry works, but typically reaction rates increase faster than linearly with temperature. So a little time while it's real hot is worse than a long time time when it's not as hot.

Re: 100+ degree weather & flashlights: best practi

Remember that any rechargeable battery will have the charge drain off over time. Don't count on 'em unless you know that they have been recently charged, and even then (just because a little paranoia is a good thing), I keep spare lithiums and/or alkalines handy.

-(a different) Craig

Re: 100+ degree weather & flashlights: best practi

My opinion is to keep your lights loaded with cells. You may need one in a hurry and won't have the time to mess around. AFAIK lithiums aren't corrosive like alkaline cells and I've yet to have one leak.

Re: 100+ degree weather & flashlights: best practi

I carried a 2D Maglite of some type ever since I started driving. Seems like once a year, I'd open it up, find that the alkaline batteries had leaked, mailed it to Eveready or Duracell, got a check to buy a new maglite, thanked heaven that I hadn't needed the light in an emergency, bought a new Maglite. . . then repeated the cycle again.

Now, I've switched to Lithiums. It's only been a few months, but no leakage so far, and I'm not expecting any. Apparently lithiums are far less prone to this problem than alkalines, but I'm still "testing".

If you're nervous about "rare" batteries, get a UK 4AA eLed, and use the more common AA types, with the option to quickly switch to cheapie alkalines when heavy use is called for. But not all lights can use lithiums, so be careful. . . I emailed Streamlight and they stated emphatically that the 3AA Tasklight and the 4AA Propolymer LED warranties would be voided if lithium cells were used. UK lights. . . no problems. Check to see with each manufacturer before you commit to purchase. I won't use a light for emergency kits that won't take lithiums.

If I spring a "lithium leak", I'll let everyone know, but no more alkalines for me in "emergency" flashlights!

Re: 100+ degree weather & flashlights: best pr

I've been wondering just why the lithiums are so much more durable in temperature extremes, so I called Energizer to ask. A couple of CPFers here in the past have hinted at the seals as being much better than alkalines.

The CSR that I spoke with said that they had built in thermal protection. I asked a few more questions that she couldn't answer, so she said that she'd have their technical department respond via email. Here's what I received:

L91 technical Advantage:


Safety Devices


Each L91 battery contains two safety devices, which are progressive as temperature increases.


Thermal Switch (PTC) - Limits the current when the temperature reaches 85 - 95 ° C. On very high rates of discharge in devices where internal cell heat is not allowed to dissipate, the PTC will temporarily increase in resistance to reduce the flow of current. After cooling, it will automatically revert back to normal condition.


Pressure Relief Vent - Operates at 130 - 160 ° C.

Re: 100+ degree weather & flashlights: best pr

Great info! Thanks all for sharing your thoughts...time to increase my supply of lithiums I guess.