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dvbl
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Why do batteries fail in the extreme cold?
Highly detailed, geeky, nerdy responses welcome. Time to educate the masses.
Highly detailed, geeky, nerdy responses welcome. Time to educate the masses.
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Tom Rankin
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dvbl said:
Not so geeky. They don't truly fail, they work on chemical reactions, that proceed more slowly in lower temperatures, as do most (but not all) chemical reactions. Quite often, when warmed up, they work just fine again. I know my camera batteries work this way. If I hold them in my hand, they will be good for a few more pictures, several more times.
Poeple used to ( still do ? ) store batteries in the freezer. It impedes the loss of battery life, by slowing down the chemical reactions. Most people don't seem to do this these days, but it certainly doesn't hurt.
I'm sure more geeky responses will follow shortly!
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Kevin Rooney
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Not all do - lithium, for example, do not.
Will defer to Doug for HD explanations re: ion exchange, etc.
Will defer to Doug for HD explanations re: ion exchange, etc.
DougPaul
Well-known member
Lithium will also exhibit reduced output in the cold... From what I have read, it is ok to -40 or so. Most of us don't use our electronics below that temp...Kevin Rooney said:
Not sure what an "HD explanation" is...
Tom's explanation of the chemistry slowing down in the cold is correct.
And I, for one, keep my unused batteries (and film) in the refrigerator.
BTW, NiMH cells will keep their charge longer if stored cold.
Doug
Pete_Hickey
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You haven't asked this, but you may be interested in my method for keeping batteries warm.
I sewed a little pocket on the front of my underware. It always tends to be warm there, much warmer than my pockets. I keep my spare batteries there, along with a couple pouches of GU or some such gel (make sure the GU is not leaking... talk about a mess!)
I sewed a little pocket on the front of my underware. It always tends to be warm there, much warmer than my pockets. I keep my spare batteries there, along with a couple pouches of GU or some such gel (make sure the GU is not leaking... talk about a mess!)
Kevin Rooney
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Doug -DougPaul said:
HD = Heavy Duty.
NiMH are fairly reasonable, so I have accumulated about 30 of them. I have a small plastic container in my home office to hold freshly recharged batteries, so my wife or I need to swap a set, the discharged ones are popped into the charger and a new set removed from the container. There's no waiting for the freezer batteries to come back to life.
Kevin
David Metsky
Well-known member
Most battery manufacturers no longer recommend storing batteries in the fridge or especially not the freezer. Modern batteries don't discharge at room temperature like older ones used to. You can safely store them in a cool dry place for years without losing any appreciable charge.
From Rayovac:
From Kodak
From Duracell
So, for alkalines, don't bother putting them in the fridge and keep them out of the freezer. It will help charged NiMH batteries as they discharge fairly quickly, but I just pop them in the charger the night before I need them, so it's not an issue of storage.
-dave-
From Rayovac:
From Kodak
From Duracell
So, for alkalines, don't bother putting them in the fridge and keep them out of the freezer. It will help charged NiMH batteries as they discharge fairly quickly, but I just pop them in the charger the night before I need them, so it's not an issue of storage.
-dave-
SAR-EMT40
Well-known member
Pete_Hickey said:
You may want to consider moving that pocket to the inside of your jacket. You don't want to even know the injuries I have seen from batteries in the front pockets of peoples pants from leaking acid or a short circuit with coins or other metal objects. I always carry my batteries on the inside of my jacket. Thats as personal as I want to get with them.
Keith
Quietman
Well-known member
SAR-EMT40 said:
So right, I was amazed at how much heat a couple of AA Nimh batteries and a quarter in my pants pocket could generate. So were my co-workers while watching me dancing around trying to get them out of my pocket.
SAR-EMT40
Well-known member
Quietman said:So right, I was amazed at how much heat a couple of AA Nimh batteries and a quarter in my pants pocket could generate. So were my co-workers while watching me dancing around trying to get them out of my pocket.
NiMH aren't the worst ones if IIRC. NiCD are the worst as they have no internal resistance, unless I have them confused in my head. I'm sure Doug will correct me if I got those mixed up.
If they short they can dump an incredible amount of current (albeit for a short time) through whatever it is shorting on. It can make a penny almost glow. I would expect lithium to be very bad for shorting also as they possess very high current capacity though I can't remember how rapidly they can release it. I am sure it is fast enough though. Keith
DougPaul
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I have quite a bunch of NiMH AA and AAA cells too...Kevin Rooney said:
NiMH cells are good to ~-20F -- -10F or so, so there isn't usually any need to wait for them to warm up, unless you are worried about condensation.
I also recharge when I remove them from the equipment. However, they will self-discharge slowly in storage. Top the charge off if you want max capacity. (This is ok to do with NiMH, not a good idea with NiCad due to the "memory effect".)
And use a good quality "smart charger"--makes a big difference in cell life.
Doug
DougPaul
Well-known member
Alkaline cells self-discharge more slowly than they used to. A refrigerator may be cooler than necessary, but won't hurt them--just make sure condensation isn't a problem when you remove them. (Or warm the cells up before using them.)David Metsky said:
The strategy of topping-off NiMH cells just before using is reasonable--NiMH cells have a noticeable self-discharge rate at room temp (particularly bad on a hot summer day...). (As noted earlier, this is not a good strategy for NiCad cells and use a good smart charger.) It is best not to allow Lithium Ion (LIon) rechargable batteries get too discharged--they can be recharged at any time.
Doug
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DougPaul
Well-known member
SAR-EMT40 said:
SAR-EMT-40 said:
Both NiMH, NiCad, and LIthium cells are capable of very high short-circuit currents. (Correct, NiCad has higher short-circuit current than NiMH.) As noted, people have gotten burned by heating due to these high currents. The cells can also overheat and release potassium hydroxide (lye) resulting in chemical burns.
Carry your spare cells in a manner in which they cannot short: ie plastic carriers are good; with coins, keychains, etc is asking for trouble.
Doug
Kevin Rooney
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I scored a little carrier at Interop/Networld a few years ago. It's a little nylon zippered case advertising Lexar Media. Inside is an elastic strap on either side for holding a memory card. Instead, I carry 2 AA's on either side for my GPS. When they're charged, the positive side points outward, and I reverse it when they need a new boost. If I carry my GPS Vista all day in the cold, I usually have to put in a fresh pair around 2PM. (I realize that's not an issue for the compass and sextant crowd ... Opps, wrong thread.)DougPaul said:
Kevin
Pete_Hickey
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Hey. Ain'T nothing short in my pocket.SAR-EMT40 said:
I did it with a penny and a 9 volt. It took me some time to realize what was happening. I thought what I was feeling was the result of something I picked up from the previous night's escapades.Quiet man said:
FWIW, my battery/powerbar warming pocket has nothing that would cause a short circuit.
DougPaul
Well-known member
Thomas Distributing http://thomas-distributing.com carries light-weight plastic battery cases. I have a bunch--they frequently come free with a purchase of NiMH cells.Kevin Rooney said:
Probably available in lots of other places, too.
BTW, TD is also a good place to get NiMH cells and chargers. (My current favorite charger for AA and AAA cells is the Maha MH-C401FS.) Reviews of AA NiMH rechargables can be found at http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM and professional-level information on batteries can be found at http://www.batteryuniversity.com/index.htm.
(standard disclaimer: I have no connection with the above companies.)
Doug
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roadtripper
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Question I've Had
I've had this question for quite a while now, and haven't gotten a chance to ask it...
How do batteries hold up with consistently varying temperatures? For instance, if a lithium battery is carried while winter hiking when it's -20 degrees out, then you go home and store them all summer long in your attic (which is @ 85 degrees), how well are they going to perform the next time you are hiking @ -20 degrees?
VERY curious as to the answer. thanks!
- Greg
I've had this question for quite a while now, and haven't gotten a chance to ask it...
How do batteries hold up with consistently varying temperatures? For instance, if a lithium battery is carried while winter hiking when it's -20 degrees out, then you go home and store them all summer long in your attic (which is @ 85 degrees), how well are they going to perform the next time you are hiking @ -20 degrees?
VERY curious as to the answer. thanks!
- Greg
skidoc22
New member
NIMH in cold
I have been very disappointed with the cold weather performance of my Powerex 2300 batteries, even fully charged they last a small fraction of the time that they do at room temp. I am not talking about subzero - even at 20-30 deg F they barely are functional in my digital camera and after a handful of photos they are dead. I have tried warming them afterward and they may have some charge left but still not a lot. My energizer 2500s seem to be far superior but still have much lower performance in the 20 - 30 range. I have tried the recondition setting on the charger but to no avail.
DougPaul said:
I have been very disappointed with the cold weather performance of my Powerex 2300 batteries, even fully charged they last a small fraction of the time that they do at room temp. I am not talking about subzero - even at 20-30 deg F they barely are functional in my digital camera and after a handful of photos they are dead. I have tried warming them afterward and they may have some charge left but still not a lot. My energizer 2500s seem to be far superior but still have much lower performance in the 20 - 30 range. I have tried the recondition setting on the charger but to no avail.
DougPaul
Well-known member
The self-discharge rate of a battery is a function of temp--faster at higher temps. There are also temp limits for batteries--too hot and they will vent (a safety valve releases to prevent explosion), don't know if they will be damaged by extreme cold (-60F or lower kinds of temps).roadtripper said:
So there may be some loss of capacity depending on the temp history. (I wouldn't store my batteries in a hot attic--living area or colder is better.) Let us also assume that you have kept the battery within reasonable storage temp limits (ie not damaged by the temp). Then the battery should only show the effects of the lost capacity next time you use it. (This is my best guess.)
Lithiums have a rectangular discharge curve--that is, the voltage stays constant until the battery is fully discharged and will drop down in only a few minutes. (The cell is essentially exhausted at this point.) So, if a lithium cell is somewhat discharged, it will simply shorten the run time, but the voltage should be ok until the end.
Doug
DougPaul
Well-known member
Kind of hard to tell from a distance... NiMHs should be good to -10F or -20F or so. (See http://www.batteryuniversity.com/index.htm.)skidoc22 said:I have been very disappointed with the cold weather performance of my Powerex 2300 batteries, even fully charged they last a small fraction of the time that they do at room temp. I am not talking about subzero - even at 20-30 deg F they barely are functional in my digital camera and after a handful of photos they are dead. I have tried warming them afterward and they may have some charge left but still not a lot. My energizer 2500s seem to be far superior but still have much lower performance in the 20 - 30 range. I have tried the recondition setting on the charger but to no avail.
Perhaps the 2300s are damaged. There are several ways to damage them: overheat during charge, overcharge, reverse charge (occurs when you have several cells in series and run them down to zero--some of the cells are slightly weaker than others and can be reversed by the stronger cells under these conditions). They also don't last forever--spec is a max of ~500 cycles if you treat them well.
Don't know how good your charger is--some of them almost guarantee that you will damage NiMH cells in typical use. Or it may not be charging them fully.
Comments on chargers for NiMH cells: You want a smart charger--one that senses the charge level of the battery and shuts off when full. (Timer-based chargers are almost guaranteed to damage your batteries.) If the charge is too fast, it will overheat the battery--you want >=2hr for AA cells. (I normally use a somewhat slower charge (slow setting on the MH-C401FS) to keep the battery temps down.) I have a 1hr charger which overheated and damaged some of my cells. If you have a 15min charger, it should be used only with cells specially designed for it--it will likely damage any other cells.
It is also possible that there is something wrong with your camera.
I have used NiMH rechargables in my headlamps, digital camera, and GPS in winter. Haven't had any problems yet...
You might consider carrying lithiums as backups. Lightweight and should work if the NiMHs fail.
Doug
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