[Red Liner]

Originally Posted by SS-Traveller

Extra memory cards & extra batteries are so important in these high altitude cold regions. My camera batteries had their charge capacity reduced by half, and just because I had the inverter running to charge one battery while using the other, I didn't run out of batteries.

I've been doing some reasonable high altitude trekking recently (18.5k ft) and have noticed that my eneloop rechargeable batteries just discharge like a mule which hasn't eaten for a week. According to Yahoo Answers:

"It's not the altitude per se, but the temperature (temps tend to decrease as you gain altitude). Batteries rely on chemical reactions to produce their electricity. Colder temps make chemical reactions slow down...so less electricity produced.

Keep your batteries warm. Perhaps carry your camera under your coat. When I was in Antarctica, I constantly had my camera under my coat next to my body.

On occasion (not thinking), I would lay my camera on my sled and putz around camp. When I got back to my camera, the batteries would be dead. I would take them out of the camera and put them next to my body or hold them in my hand and after a few minutes they had warmed and would work again. Or I would put my camera in the tent, where it would warm up. Or I would change out the cold batteries with a warm pair I carried in my pocket."

Now, for trekkers - we can't carry an inverter around like SS-Traveller above - what do we do? Is there some kind of insulation pack in which we can put the batteries in?

Please remember that trekkers have to be as light as possible. So your suggestion of a solution must keep that in mind.

As an afterthought - would aluminum foil work as an insulation material? or maybe even an empty thermos bottle?

[sgiitk]

Aluminium foil will be a good reflector but hopeless as insulation.

[anandpadhye]

Originally Posted by Red Liner

Is there some kind of insulation pack in which we can put the batteries in?

I hae not trekked to such altitudes yet, but would like to, in the future.
Just curious - does a regular thermos flask work up there? If so, is there a compact one available that we can buy?

[SS-Traveller]

Originally Posted by Red Liner

...for trekkers - we can't carry an inverter around like SS-Traveller... - what do we do? Is there some kind of insulation pack in which we can put the batteries in?
...would aluminum foil work as an insulation material? or maybe even an empty thermos bottle?

Al-foil is going to work exactly the opposite way, since it's a good conductor - it will not only keep the battery colder, you also risk short-circuiting the battery terminals. Thermos bottle - that's an interesting proposition - someone needs to experiment with a warming a thermos bottle with hot water, then drain it dry, and then store a battery in it to check the result.

For cameras that use a USB charger (and for phones & iPods) it may be a good idea to use this to extend battery life:
http://tech2.in.com/reviews/general/...er/215732#show.

I intend to try this out in extreme cold this winter, and should be able to report on the pros and cons in a couple of months.

[ilangop]

Hi,
The best analogy for Li-Ion battery would be a human. As much that we find difficult to stay active in a very cold / very hot region, the batteries behave the same way.
You may probably wrap the batteries inside a woolen glove / socks which is dry enough.
Metals are good condutors are heat. So they cant keep things warm, and hence there is no added benefit of using an Alufoil. By chance if the battery teminals happen to get shorted due to Alufoil, there would be an explosion due to thermal runaway.

[Sprucegoose]

maybe custom make a jacket for your battery operated devices...
you now like a sir and all..

Tiny 3 piece suits for all your devices

[Jaggu]

Aluminum as sgiitk mentioned will not work, best is to invest in some warm packs for these devices and yes low temp means battery can go kaput also, apart from not holding charge. Also the humidity can be a killer for electronic devices. Photographers carry something like this also http://rasikaambe.blogspot.in/2008/0...a-dry-box.html dont know if they have warmers also.

[Red Liner]

Originally Posted by anandpadhye

I hae not trekked to such altitudes yet, but would like to, in the future.
Just curious - does a regular thermos flask work up there? If so, is there a compact one available that we can buy?

The one I have works just for 4 hours at extremely high altitudes (can keep stuff warm or cold) - and is light. That was important for me. I don't want to end up carrying a ton of steel. But 4 hours is not the most useful - as I found out later.

I guess a good DIY option for ultimate insulation is to put all the batteries into a -20 degree comfort sleeping bag (which you'll end up carrying anyway) and package the whole thing in. Considering these things keep you at body temperature at -20C, this should work.

Albeit, you need to remove the entire damn thing to get the batteries out...which is a horrible chore. Just packing the bag in takes a good 10 minutes and a lot of arm and foot work. So am looking for a simpler DIY option.

The other issue is I can't keep the batteries in the device itself after using them. They'll simply discharge due to the cold. So I'll need to take them out as soon as duty is done and put them back in this "non existent cheap DIY battery insulator".

Can someone list out all good foldable/light insulators? Will help in the brainstorming.