Batteries in cold weather

[Giddy_up]

Just wondering what peoples experiences are with batteries and power packs like Mophie etc in really cold weather or hot weather for that matter. Do they loose charge quickly, do you have to keep them warm/cool or insulated to maintain their power and what tricks do people use to conserve that power.

Given that our lives are now crowded with electrical devices and we bush walkers are using more powered equipment, what are the ramifications in extreme weather. I was thinking about how this may impact on safety devices after reading Moondog's report from Pretty Valley. After 3 weeks in some very cold conditions would a PLB work to its capacity and how long before the batteries would fail. I also assume that if the PLB batteries got cold enough to fail so would the spares in the backpack.

I am curious to find out what the performance of a PLB in those conditions would be, and does any one have experience on this. Is the signal weak or does it just get transmitted for a shorter period of time before stopping. Either way it's less than desirable if you have to push that button for help.

[icefest]

PLB batteries are a different chemistry to most other batteries. LiMnO2 is good to well below -20 deg c.
Most primary lithium batteries are OK at low temperatures.


Other than that, store them in pockets before use (in a sock, tucked in the inside of your pants works well ).

[Moondog55]

PLBs should use long life Lithium batteries which should perform down to -30C or lower
My experience says that bigger batteries are less effected by the cold than the little AAA but keeping them in an inside pocket helps a lot. As noted in my report I'm changing most of my headlamps to use AA or bigger

[Giddy_up]

Wow I didn't realise that batteries could function at -40C. That's very cold!!!!!!!!!! I guess if its below that temp and you need help, it's not going to get to you in time.

[icefest]

I always use single use lithium batteries in winter (CR123a or lithium aa). You can buy them online for 1$ each and they have a much larger energy density than alkaline.

Here is the duracell spec sheet for LiMnO2 http://ww2.duracell.com/media/en-US/pdf ... lletin.pdf

The legally mandated minimum operating time of PLB's (48hr 24hr AFAIR) is based upon worst case senario. Minimum temperature, end of life, after max self tests.
Most PLB's are rated to -20c which is rare as ___ in Australia (-22 record for Charlotte's pass)

TL;DR, Use expensive batteries in winter, keep them warm if possible.

EDIT: 24hrs not 48

[ofuros]

The three spare batteries I use for my camera, are usually keep in my pockets during the day(in a ziplock bag)
At night with dropping temps they're placed in my make shift pillow, heat from my head keeping them warm until morning.
Works like a charm.

[Giddy_up]

Are those lithium batteries in PLB's the same as you buy in the shop, ie. Duracell or are they more specialised.

[icefest]

When doing PBL research, they were the only ones mentioned, that being said, it was only 2 PBL's that mentioned them. (I do not remeber which ones)
They were energizer AFAIR.

[South_Aussie_Hiker]

I use lithium primaries exclusively when Bushwalking.

Their power will always match or exceed NiMH or alkaline.

They do not suffer like alkaline in high current devices (where internal battery resistance ends up consuming most of the energy by heating the battery up).

They have a very long shelf life.

They are half the weight of a similarly sized NiMH.

They have excellent low temperature performance.

And most importantly, they don't leak. There are some devices at home where I just won't use an alkaline for fear of leakage. A leaked battery in a GPS might cost you a $300 GPS, but if it leaks while you are walking it could end up costing you your life.

Alkalines should be reserves for cheap, very low drain devices you are prepared to throw away (like a simple wall clock).

NiMH should be for high use devices where there are environmental and cost benefits, but not in extreme environments (like severe cold) or where batteries sit idle for very long.

Lithium primaries should be used in expensive equipment where NiMH is not suitable, and whenever your life could potentially depend on it.

Just my 2c.

[icefest]

Below -20 is below the recommended specs of almost all PBL batteries. It would decrease operating time.

The exception is Lithium Thionyl Chloride and single pile LiMnO2. Both of which are less affected by temperature but cannot supply much current at all. Useless for this activity.

Self discharge is usually decreased by decreasing temperatures, with some chemistries being damaged by freezing. Your best bet is to find out the chemistry of the battery and then do some research.

Buying bulk online, you can expect to pay 2-3$ each. (CR123 and AA lithium)

[Don R]

As regards cold weather, on a 2008 trip through the Traveller Range etc I got over 900 shots from my battery for my Nikon 40 DX whilst my mate only got 400 out of one battery for D60. Same battery, very similar cameras. The difference was that I kept the batteries in my vest pocket during the day and they were inside my sleeping bag at night (it snowed on a couple of days) whilst my mate left his camera in his pack.

[Giddy_up]

Thanks every one for the info, it sounds like the better batteries can handle the cold more and keeping them warm also males a huge difference in performance. I also hope as a QLD'er that I never have to survive in temps below -20 C or have to rely on any batteries beyond -20 C.

[Ent]

Hi

Primary lithium batteries are no doubt the best in extreme cold but sadly we pay way too much for them in Australia. Alkaline batteries, especially Duracell I have found leak even if well within their use by date and almost certain once passed it.

Actually Sanyo Eneloop batteries perform very well in cold say minus five. The real surprise is the iPhone battery. They are terrible as after half an hour or less at sub zero ambient temperature they fail. Strangely the l-ion battery pack on the Garmin 650 Rino is rather unfazed by the cold.

Batteries prefer to be warm but again with the exception of Duracell lithiums that went flat in half an hour in my GPS I have never had a problem with other brands of lithium and the mentioned Sanyo Nimh batteries.

I have yet to find out why all batteries are not created equal despite the same chemistry but genuine camera l-ion batteries generally way outperform after market clones especially in the cold. Strangely my Canon 90s are the worst with about the same size Olympus much better.

Cheers

[Giddy_up]

Thanks for that Ent. It is odd that the chemistry can be so different in a product that is essentially badged the same, also those iPhone numbers are very scary as some people might rely on that as their sole source of contact in an emergency without fully understanding their need for an appropriate PLB.

[Area54]

I took a few power sources to Iditarod this year - I had a power monkey extreme battery as my main power bank - this lived in my jacket pocket the whole time (same clothes for riding all day and in bivvy each night) This was for charging my exposure diablo light (sealed internal lithium batts) and Garmin 800. The Garmin failed to turn on after a few days - but it was more of an experiment in temp limits than a tool for field use. It was down to -30C, so can't complain. I took extra batts for the camera, again they lived in a pouch in my jacket pocket. Mammut headtorch used simple alkalines - when the torch wasn't in use, it was around my neck under a neck sock. I think I used 3/4 of the capacity of the power monkey. The garmin was the only device truly out in the elements, next was probably the diablo, but it was on a headstrap, over my ski mask but under my hood.

My simple rule was always keep the batts warm, regardless of type, and where possible, rely on technology as little as possible.