Help me understand how best to manage batteries in cold weather. I know charges don’t last as long and battery life times are shorter. But does anybody know exactly why? More to the point, are the energy losses permanent or temporary (i.e., will the lost power come back again when it warms up)?
I went canoeing a few days ago with a new camera. I had two freshly charged batteries in it. However, this camera had already shown signs of being a power hog – some days I’ve only been able to take a few dozen pics before the low-battery light comes on. So, I wasn’t too surprised when it refused to work in the cold. I had charged the batts about 5 am and put them in the camera and put it in my gear and drove to the river and launched the boat and paddled a while and then about 8 am I tried to take a picture, and the batts were so low the lens cover wouldn’t even retract. The only action was the screen lighting feebly and saying insert new batteries.
But what surprised me was that today, after the camera had been sitting inside for a couple days, it worked fine and I was able to take it out to the shop and take about a dozen pictures on those same batteries.
So that got me to wondering, would my camera have worked on that cold day if I had kept the batteries on me (and thus kept them warm), say in my pants pocket, for the 5am to 8am period after charging? Or how about if I had let them get cold like I did, and THEN I put them in my pocket to warm up – would they become more powerful when they were warmer? Or did I need to warm up the whole camera, so that the wires that carried the electricity would also be warm?
Here’s another, related question. I also carry a deep cycle battery in my jeep, mainly for a trolling motor I use on a different boat but also to provide power in the car for different things. I like to carry the max possible charge on this as I often use it all up on a trip. I usually charge it the night before a trip, and I have a charger set up in the garage so I don’t have to take the battery out of the vehicle. Add in the fact that I usually try to leave on my day trips a little before dawn, and the current weather forecast is a low of 20 tonight and high of 50 tomorrow.
So, if I charge it in the car as usual, the battery is going to be about 20 degrees when I take the charger off and leave. Alternatively, if I haul it into the house and charge up there, it will be closer to 70 degrees. Will I gain enough extra juice in the battery to make it worthwhile to carry it back-and-forth to the house?
What type of batteries?
If AA, then you could use Energizer Lithium when you take the camera out in the cold and they’ll work much, much better than NiMh rechargeables.
For more information on batteries than you’ll ever really want, go to candlepowerforums.com http://www.candlepowerforums.com/vb/forumdisplay.php?f=9
They’ll answer all your battery questions.
Chemistry
Most batteries work better in warm weather. The chemical equations are faster in hotter temperatures until it gets so hot the battery gets damaged. Most batteries can also be damaged by freezing but they don’t freeze as easily as water.
Your charged cold batteries still have a good charge it just cannot get out very well. The best bet is to keep the whole camera inside your coat where your body heat keeps it warm. Warm batteries put in a cold camera will get cooled quickly by the camera.
For your non camera battery charging and discharging work best at normal room temperatures. If you bring it inside and let it warm up it will take a charge much faster. If it is really cold it may seem like it won’t take a charge. Once you take it out of the garage, can you keep it warm while you are using it?
Camera Batteries in Pocket
I find that keeping the camera battery in my pants pocket helps a lot. In near-zero weather, my camera (which also seems to be a power hog) won’t work unless the battery is warm. The battery should be fine as long as it is warm. I’ve only done that a few times, and did not notice a significant reduction in battery life compared to normal shooting in warm weather. If it starts to die from being cold, it will come back to life once warmed up again.
I recommend AGAINST putting the whole camera inside your coat, as condensation will be severe. That can temporarily stain the lens (it’s a pain to deal with regardless) and it’s potentially bad for the electronics stuff. Remember, condensation will form anywhere air can reach, and that will include the camera’s innards. If the camera were warm the whole time it wouldn’t be so bad, but once it cools (as it will when you use it), putting it inside your coat can drench the thing in an instant (eyeglass-wearers know all about this stuff).
As to your deep-cycle marine battery, have you actually noticed a decrease in power output at 20 degrees? I’m sure there is some decline in performance, and it may be more pronounced than for a regular car battery since a deep-cycle battery is “slower” in all ways (slower to charge AND slower to discharge (less capable of putting out high amperage)), but I’d be surprised if it’s enough to worry about. Again, that battery will charge just fine outdoors, but I wouldn’t be surprised if it takes a bit longer (I’ll leave that to the experts, but charging involves a chemical reaction too, so I’m guessing the reaction goes more slowly for a given rate of power input when the battery is cold).
batt temp
"Once you take it out of the garage, can you keep it warm while you are using it?"
Not directly, but for the first hour or 90 minutes I’ll be driving with the heater on, and then the car itself will hold some heat for a time after that. Thus, on a typical low-20-high-50 kind of day, the battery temperature would probably be 70ish early on declining to 50ish mid-day and still near 50 by the time I return to the car. By contrast, charging it outside, it would probably be 20 to start, warming to 40-50 on the drive, then declining or holding steady the rest of the day.
power loss when cold
"As to your deep-cycle marine battery, have you actually noticed a decrease in power output at 20 degrees?"
I think so, but I haven’t been precise enough yet to be sure. I’ll try to pay closer attention. Actually, now that I think about it, maybe there isn’t a power loss - I was really just kind of assuming that from the general principle of batteries not working as well in cold.
My most power-draining use is a luxury, to grind and brew fresh coffee on the drive down and back. There are, of course, many other ways to do this, but using the battery is the most convenient. In really cold winter weather, I sometimes use up the whole battery making 2 or 3 cups of coffee over the course of a day, while in milder temps I can make 5-6.
Of course, what I just realized above is that the water is starting out colder so it takes more power to boil a single cup, and that might account for all of the difference.
But wait - isn’t the power required directly proportional to the number of degrees by which the water is heated? If my starting temp on the water is 35 on a cold day versus 70 on a warm day, and my output is 3 cups cold day versus 5 cups warm day, then 3*(210-35) would have to equal 5*(210-70). Since it doesn’t (525 vs 700), then there would have to be a power loss, right? (Assuming the various numeric inputs, 3 vs 5 cups and 35 vs 70 degrees, are correct or on the conservative side, which I think they are.)
thanks
Thanks for the forum link and mention of lithium batts, that may be the answer for camera batts, but cost is a concern. I see disposables as cheap as $1.50 each - I’d rather have rechargeables, but it gets confusing quick. Apparently not all rechargeable AA Lithium batts are a direct swap for normal AA batts? Hmm, I’ll need to read up some on that forum.
“restore science to its rightful place”
“We will restore science to its rightful place…”
It seems as if p.netters are taking President Obama’s assertion to heart 
Don’t forget
Charging many wet cell type batteries produces gasses which can explode. Keep that in mind if you charge indoors.
Tom
exploding gases
Only a problem if exposed to flame or spark before they can dissipate. I once witness a fellow’s car battery (which was charging) blow up when he leaned over it with a cancer stick in his face. No spark, no flame, no worries. Make sure you unplug the power source on the charger before disconnecting the battery.
Lithium batteries
They do work better in cold. And they last longer besides. You may find that the price difference isn’t all that great when you do the math.
In the past, lithiums had some notoriety for making a fizzy mess if they became wet. I don’t know if that’s still true, but I would make sure my battery compartment has a good seal.
Some questions…
What kind of camera do you have?
What kind of batteries are you using?
Not all NiMH are the same, some are 1850maH and others are 2450maH. Older Energizers are the 1850, mixing capacities will reduce available capacity.
specs
The new camera is a Canon powershot A560 with 4x optical zoom, 7.1 mp. It uses 2 AA batts.
The old camera is a Konica/Minolta Dimage Z10 with 8X optical zoom, 3.2 mp. It uses 4 AA batts.
The batteries are an offbrand, Dahann (with two dot accent marks over each one of the A’s) that I bought over ebay from somebody in Taiwan. They’re rated 2500 mAh. I’ve got 25 of them and I use them in several different gadgets, and they seem to work fine in the other gadgets. However, I don’t know if they achieve the 2500 mAh advertised - is there some way to measure that? I have a multi-meter.
The Canon obviously expects a stronger battery. At normal temps, with fully charged batts, it starts out showing the battery at 3/4 strength (not 100%). Then, it will only take a few shots before it begins to warn of “low battery” and goes into power saving mode, where the screen stays mostly blank. However, it will usually stay in that mode for a long time (like 2-4 hours of off-and-on operation) and take 100-200 pictures before it will refuse to operate.
fire
I guess I’ll buy a couple of the 2950 mAh disposables to give them a try. I’d rather find rechargeables, though, because at $1.50 each the disposables are WAY more expensive than my 6-7 cent cost per use of the Dahann rechargeables, and I like to take a bunch of pictures.
Anybody know why the lithiums perform better in the cold?
Aren’t lithiums more subject to catching fire while recharging? I seem to remember that those laptop fires a few years ago were blamed on lithium batteries. Also, one of the sites I found that sells lithium rechargeable AA batts recommends charging them inside a fireproof container. Does anybody know what makes them liable to catch fire?
Heat?
Only thing I ever heard about lithium batteries catching fire (not lithium/ion rechargeable) was that if they short out (as in improper storage), they deliver current fast enough to make enough heat to start a fire. This was specifically in reference to the cr123 camera batteries, but I don’t know if it applies also to the AA and AAA sizes.
Lithiums are NOT rechargeable.
Litihium ions are rechargeable.
The Energizer e2 Lithium disposeable batteries are not rechargeable and I’m not aware of any danger of fire with them when used as directed.
My understanding, which is by no means complete or expert, since I don’t use lithium ion reghargeables, is that they have on occasion cought fire, exploded or “vented”. The candlepowerforums people are much more expert on this than I am. CR123 lithium ion batteries vary greatly in safety and reliability from brand to brand and also vary as to whether they are “protected” cells or not protected.
Nernst Equation
http://en.wikipedia.org/wiki/Nernst_equation
briefly delta G zero = delta H minus (Temperatue*entropychange)
exploding laptops, phones
This has been an occurrence that’s been documented within recent years, Lithium ion batteries being the culprit. Not saying they’re bad, but quality manufacture is important.
It’s Ebay junk batteries!
I’ve got the new Canon PowerShot A1000, which also uses 2 AA batteries. The Energizer 2450’s last a long time, much longer than my older Kodak DC5000 which uses 4 AA bateries.
cost vs value
Yeah, I looked at the A1000 (successor to the A580), and the top-of-the-line A2000 also. As with most electronic gadgets, there seemed better value in the model a couple steps down from the top. 7 mp is already overkill for me, so it didn’t bother me to pass on the 10 mp, and most of the other features are the same. At almost half the price of the A1000, the A560 looked like a bargain.
I follow a similar philosophy on batteries, more so even since they can wind up costing more than the camera itself over time. I’m perfectly willing to buy off-brand. Even if the performance is inferior, they can be a better deal, dollar for dollar. However, I do try to measure their performance relative to name brand stuff. Prior to this camera, I didn’t really have any reason to complain, but now I guess I should pick up a couple Energizers on my next battery purchase to see how they compare to the off-brand stuff.