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Activations at sub zero C

And IT was extremely cold! :wink:

Buffalo: http://www.buffalosystems.co.uk/

The other is a down filled jacket.

Seems to me that using the heat dissipation of the radio to warm the battery might be a runner…
However, having a good idea is one thing, putting it into practice quite another!

Mark. M0NOM

Thanks. I have a British Army Smock in olive color that looks like those Buffalo wind shirts. Curious if they’re made by that company. Google search led me astray in looking for info on “Erve Duvet” and pointed me to down comforters :wink: Also in my travels picked up a nice new Basha in desert camo. Been an extremely nice tarp to use out and about…Always like seeing activation pictures in and reading write-ups of cold WX ops…Appreciate info…

Later…

73, Todd KH2TJ

It’s amazing the amount of heat an '817 chucks out… I transport and use mine in a clip-top cereal container (which also has room for the main battery in a further plastic container, mic, morse key, patch leads and a small spare LiPo), the LiPo sits on top of the radio and is kept toasty warm. I’ve not noticed any problems due to cold when operating down to -5C.

73 de Paul G4MD

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That looks cold, intrepid, and brave. Hope you get thermal headphones for Christmas. Pictures look brilliant.

OK so here are a couple more winter pictures,on Friday, this time on Peel Fell, G SB004 at a toasty minus 5C

View of Dead Water Fell from G SB004 with its weather radar.
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On this activation I used a 1m length of 10 gauge Turnigi silicone insulated cable to connect between the rig and the battery located in my Buffalo chest pouch. The battery voltage remained above 11.1V throughout 1hr of operating at 80W CW. After one hr the cold got the better of me though. Must be getting soft!

David G0EVV

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I have operated several times close to -30C. No problems with 3S lipos 500mAh ( I run only QRP). I keep lipos and the rig in my pocket inside winter coat during operations. In military in 80´s we sometimes had to make fire to warm slab batteries to be able to operate…

73 Marko OH9XX

Well my KX2 went a little strange on me today on G/NP-023. It started bleeping in morse and refused to change frequency using the knobs (the mic ‘up’ ‘down’ buttons still worked). I was using the internal battery and wonder if the low temperature was causing the issues. I couldn’t change bands and so after my 4th contact I decided it wasn’t the time or place to start messing around with it and go home (the mist had also descended). When it (and I) thaw out I’ll see if it has returned to full use. Temp was probably about 0C. Apologies for not hanging around any longer.

Hi all,
I have done a little research and found (not surprisingly), that as with all chemical processes, battery performance (terminal voltage and available capacity) falls faster than the fall in temperature.
The packing note that came with my Turnig batteries says the operational temperature range for LIPO’s is 4C to 49C. Clearly with my battery on the ground at an ambient of -9C the cells were well outside the operational temperature range.

Moral of the story, at low ambient temperatures, keep the batteries inside the duvet, take nothing for granted (and read the packing note).

Thanks for your comments.

Regards
David

This is an interesting paper on the performance of lithium ion cells at low temperatures. Some of it is above my head, but at one point it does suggest that simply cranking on the battery at a rate of no more than 3C in temperatures of -20C would cause the battery to warm itself through cell self-heating and avoid losing overall energy capacity (see conclusion 3.)

http://ecec.mne.psu.edu/Pubs/047304JES%202013.pdf

Yup, our EV will dump power to the pack heater rather then let the temperature drop too far. Still hurts the range but better than a cold battery pack.

The chemical hand warmer packets that I have used need a fresh supply of oxygen to work properly. Ditto for the fuel based combustion hand warmers. They would not work properly in an airtight sealed container.

As if people don’t look on us as weirdos allready? :wink:

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… and lower! If I recall correctly, it was -10C on Fountains Fell G/NP-017, but probably a toasty -5C in your snow hole by the wall! ;-)[quote=“G0FDM, post:26, topic:16447”]
Hope you get thermal headphones for Christmas.
[/quote]

My XYL bought me a Celestron FireCel electric hand warmer / torch / portable phone charger thinking it would be useful to warm my hands as I suffer from Reynauds. Such a device might be useful to keep a battery warm. The phone charging aspect will be most useful for extended activations such as the NA<>EU S2S events. I wonder if anyone else got a useful gadget for Christmas.

Several video illustrations to talk about placing batteries on the body under the clothes (above and below the belt:sweat_smile:).


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