As we were sitting around with friends a few weeks ago, the subject of household batteries came up. My husband said “Gaye, we really need to stock up on batteries”.
Ha ha I responded and took him to my storage area (which he is not allowed to touch or it will get messed up and disorganized) and pointed to a large stash of AAs, AAAs, D-sized, C-size and the often overlooked 9-volt batteries. (And why do people forget to stock up on those)? I also pointed to a year’s supply of hearing aid batteries.
Following that, the topic turned to battery storage and while I am not an expert on all things electrical, it made sense to me that batteries should be stored at room temperature – not to hot and not to cold. There is always a wise guy around though, an someone brought up keeping batteries in the freezer.
I didn’t have a clue but I did check snopes.com that said no no – batteries should not be frozen (or refrigerated for that matter). Still, I wanted, some first-hand anecdotal feedback on the matter so I asked Ron Brown, a retired industrial engineer and my go-to person when it comes to this kind of stuff.
Rather coincidentally, he had recently performed a battery test using standard run of the mill flashlights and run-of-the-mill carbon zinc batteries. Here are the results of his test.
Flashlight Batteries – To Refrigerate or Not to Refrigerate
I had a childhood friend that, when he needed flashlight batteries, got them from his mother who retrieved them from the refrigerator. Later, when I mentioned this to a college roommate, I was informed that HIS grandmother went a step further. She kept unused batteries in the freezer.
As preppers, we should probably all know the answer. Can we extend the shelf life of flashlight batteries by refrigerating or freezing them? What do you think?
One thing is certain. If you freeze or refrigerate batteries, you must let them thaw for a couple of days and come up to room temperature before using them. Your car battery, for example, might crank on your hard-starting car for 15 minutes in the summer before dying but only two or three minutes in the winter. Cold saps a batteries’ strength dramatically.
But that’s in use. In storage, cold will slow electrical activity (leakage, in the case of batteries) and, in theory, stop the battery from running down. Or slow the battery from running down. Nothing will stop it completely. “All energy systems run downhill,” as they say.
As a child, comparing the performance of my flashlight to my friend’s flashlight (equipped with refrigerated batteries), I never saw much of a difference. But what if I conducted a controlled experiment? Would refrigeration make a measurable difference?
So, a while back I went to the store and bought six “D” batteries. They were neither dollar-store cheapies nor expensive alkaline batteries. They were Eveready-brand carbon-zinc batteries. I marked the date on the packages and put two in the freezer, two in the refrigerator, and two in the cupboard over the kitchen stove. Because of cooking heat, the last two were slightly above room temperature, both summer and winter, for the duration.
After two years, eight months and three days, I decided it was testing time. So I laid all the batteries on the dining room table for two days to thaw out and equalize in temperature. As regards the batteries stored above the kitchen stove, I really thought that they would die after just a couple of hours.
I tested them all simultaneously, side by side. I used three Rayovac-brand flashlights, all purchased at the same time, all equipped with standard bulbs (not LED, not Krypton). The flashlights were carefully labeled as to which batteries they contained.
The first thing that impressed me – amazed me, really – was how long the batteries lasted. When first started, they all appeared to give off the same amount of light; they were of equivalent brightness. After SIX HOURS they had all dimmed and needed replacement. SIX HOURS of continuous burning after 2.5 years of storage! I had expected two or three hours.
At the end of six hours they were all burning with equivalent brightness but had all dimmed. I would have been somewhat reluctant to have gone to the mailbox or out to the barn with any of them.
At the end of eight hours, they were all down to glowworm status. At this point the room-temperature batteries gave only a pinpoint of light and the refrigerated/frozen batteries a brighter glow.
BUT, as a practical matter, they all reached the end of their useful life at the same time (six hours) at which point they had equivalent brightness. You could have switched the labels around on the flashlights and no-one would have been the wiser.
I concluded that attempting to extend battery shelf-life by refrigeration was, and is, a waste of time. And that’s worth knowing, is it not? This was not, and is not, armchair theory. This was a real test with real batteries. If you repeat the test, you can expect the same results. Call it the “scientific method” in action.
Checking this out further
One thing that surprised me abut this test is that the refrigerated batteries lasted just as long in real use as the room temperature (or better) batteries. I am still wrapping my head around that one since doesn’t an automobile battery discharge itself more quickly in the dead of winter than the heat of summer. Perhaps that is my imagination.
Also, the idea of condensation would seem to be a detrimental factor when it comes to cold storage. Here is what Energizer has to say:
“Storage in a refrigerator or freezer is not required or recommended for batteries produced today. Cold temperature storage can in fact harm batteries if condensation results in corroded contacts or label or seal damage due to extreme temperature storage. To maximize performance and shelf life, store batteries at normal room temperatures (68°F to 78°F or 20°C to 25°C) with moderated humidity levels (35 to 65% RH).”
The Energizer web site included some other tips.
When stored at room temperature (i.e. 70°F/ 21°C), cylindrical alkaline batteries have a shelf life of 5 to 10 years and cylindrical carbon zinc 3 to 5 years. Lithium Cylindrical types can be stored from 10 to 15 years. Prolonged storage at elevated temperatures will shorten storage life.
A battery tester (loaded voltmeter) is a simple and effective way to determine if a battery is “good” or “bad”. Most testers place an appropriate load on the batteries and then read the voltage. A voltmeter without a load can give very misleading information and is not recommended for this purpose. Note that testers are typically not capable of providing reliable run time estimates.
Now just like week I had watched my brother test the batteries in my Kaito radio with such a gizmo. That got me thinking that I should get an inexpensive tester myself (see this TEKTON Battery, Bulb and Fuse Tester for $7).
Covering All of the Battery Bases
As much as it makes sense to store batteries for emergency preparedness purposes, nothing beats using rechargeables. My favorites are the Sanyo eneloop’s (about two dollars each, sold in packs of 4 or 8) because they hold a charge forever. That means that they can sit all charged up and ready for an extended period of time without discharging themselves. For me, this is a huge plus.
The other thing that should be in your survival kit is a solar battery charger. They aren’t expensive and give you a bit of backup power just in case you need it.
The Final Word
It was fun for me to get all of the benefits of the battery storage test with none of the work. My thanks goes to Ron for his willingness to share his work with my readers. He seems to have this intuitive sense of knowing the answers to my questions before I even ask. Pretty cool.
Finally, no article about lighting for preppers would be complete without mentioning chemical lighting. Light sticks are inexpensive, easy to use, and safe for children to use as well. Consider adding some to your kit and storing some in bedside drawers, automobile glove boxes and anywhere else you may get caught unexpectedly in the dark.
Enjoy your next adventure through common sense and thoughtful preparation!