GPS Low Temperatures

In article <[email hidden]>, Steve Crossley

URL: said:

Hello,
I am thing of buying a Garmin GPS, the basic one as I actually
enjoy compass work, but in heavy mist or a whiteout the wife might
like the reassurance of a GPS. Anyway I have read a review that
mentioned low temperature problems, has anyone any experience of this.

I've used mine ski-touring in the Alps at temperatures well below
freezing. Indeed it was so cold in the Bernese Oberland that the glue on
our skins stopped sticking to the base of our skis! I'd guess it was
between -10 and -20 C at the time, plus a windchill on top.

The effect of temperature is to firstly mean that the batteries drain
faster (for example the cells on my camera were reading half empty even
when new) and secondly the display update slows down.

However if you keep it inside your jacket between uses it will help
battery longevity and it will certainly still work.

The unit I was using was a Garmin Geko301.

Mike <URL:http://www.path.cam.ac.uk/~mrc7/>
--
o/ \\ // |\ ,_ o Mike Clark
<\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
"> || _`\<,_ |__\ \> | immunology lecturer, antibody engineer and
` || (_)/ (_) | \corn computer user"

Steve Crossley typed:

Quoted message said:

Hello,
I am thing of buying a Garmin GPS, the basic one as I actually
enjoy compass work, but in heavy mist or a whiteout the wife might
like the reassurance of a GPS. Anyway I have read a review that
mentioned low temperature problems, has anyone any experience of this.

I've had one or two problems in exceptionally cold weather with my GPS 12 (a
bit posh) just wouldn't power up at all. Once it happened near the summit of
Glas Maol (Glenshee) in a whiteout when I just wanted to know EXACTLY where
I was lost and could get the hell out of a nasty situation! :-)

Maybe it had something to do with the batteries but I can't be sure. I
ALWAYS use Duracell Ultra M3's for best performance (No, I don't work for
Duracell, it's just they're cheaper in the Tax Free shop at the airports!)

Don't forget to take your map and compass ... just as a back-up! :-s

PS Sometimes I experience the same problem with the digi-cam ... but then
I don't use IT for navigating! ;-)

--
Andy Crawford
www.chiadfhear.co.uk

Remove "my boots" to e-mail me

In article <[email hidden]>, Steve
Crossley <[email hidden]> writes

Quoted message said:

Hello,
I am thing of buying a Garmin GPS, the basic one as I actually
enjoy compass work, but in heavy mist or a whiteout the wife might
like the reassurance of a GPS. Anyway I have read a review that
mentioned low temperature problems, has anyone any experience of this.

I have used GPS in the north of Russia in winter. The trick was to keep
it inside your clothing and just take it out when needed. The following
photo was taken at about -20C.

http://www.matley.co.uk/photo/eTrexRussia.jpg

My glove was off so that I could fiddle with the buttons to rename the
marked waypoint (~67N 57E). Once the photo was done the eTrex was inside
and the gloves on pretty quick.

Garmin lists the temperature range (-15C for the eTrex pictured above)
of their units on their web site and other manufacturers probably do the
same. The main problems with the cold are:

1. The LCD screen gets very sluggish and can loose contrast.

2. The batteries stop working when cold.

Lithium batteries can be used to overcome 2 to a degree but both are
helped enormously by keeping the unit inside your clothes until needed.

I am sure that UK conditions will not be a problem if used sensibly.

--

Dominic Sexton
http://www.dscs.demon.co.uk/

Bitstring <[email hidden]>, from the
wonderful person Steve Crossley <[email hidden]> said

Quoted message said:

Hello,
I am thing of buying a Garmin GPS, the basic one as I actually
enjoy compass work, but in heavy mist or a whiteout the wife might
like the reassurance of a GPS. Anyway I have read a review that
mentioned low temperature problems, has anyone any experience of this.

Neither LCD displays nor NiMH/Alkaline batteries much enjoy sub-zero
temps. For batteries, using Lithium, or Li-Ion, fixes the problem
(assuming the device can cope with the rather higher voltages these can
deliver). However since the LCD will still be suffering (problems
ranging from very slow display updates, to not working at all), it's
just as easy to keep the whole thing inside your pocket until you need
it (most =dry= cloth is perfectly transparent at the frequencies
involved). You body will quit at a way higher temperature than the GPS
will - the Etrex is specified to operate down to -15 (and doesn't suffer
from wind chill). 8>.

--
GSV Three Minds in a Can
Outgoing Msgs are Turing Tested,and indistinguishable from human typing.

"GSV Three Minds in a Can" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Neither LCD displays nor NiMH/Alkaline batteries much enjoy sub-zero
temps. For batteries, using Lithium, or Li-Ion, fixes the problem

//snipped//

Are there measurements to support that statement about NiMH cells? Technical
support of a reputable battery manufacturer recently advised me that their
NiMH cells "can operate in discharge down to -30°C". I have successfully
used AA NiMH batteries at temperatures well below -20°C, but I have not
tried them with a GPS at such temperatures. [Easy to test in a deep-freeze,
I suppose].

--
Alan Law

Alan Law said:

"GSV Three Minds in a Can" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Neither LCD displays nor NiMH/Alkaline batteries much enjoy sub-zero
temps. For batteries, using Lithium, or Li-Ion, fixes the problem

//snipped//

Are there measurements to support that statement about NiMH cells?
Technical support of a reputable battery manufacturer recently advised me
that their NiMH cells "can operate in discharge down to -30°C". I have
successfully used AA NiMH batteries at temperatures well below -20°C, but
I have not tried them with a GPS at such temperatures. [Easy to test in a
deep-freeze, I suppose].

Picking a manufacturer and cell type more-or-less at random this data sheet:

http://www.saftbatteries.com/130-Catalogue/PDF/VH_AA.pdf

shows that both the ultimate capacity and discharge voltage of NiMH cells
reduce at low temperatures (graph on page 2). Depending on the requirement
of your GPS the voltage even fully-charged may be too low for it to work at
all.
--
Dave

In article <[email hidden]>, Alan
Law <[email hidden]> writes

Quoted message said:

"GSV Three Minds in a Can" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Neither LCD displays nor NiMH/Alkaline batteries much enjoy sub-zero
temps. For batteries, using Lithium, or Li-Ion, fixes the problem

//snipped//

Are there measurements to support that statement about NiMH cells?

I doubt it. Energizer's NiMH AA spec sheet says they operate down to
-20C.

http://data.energizer.com/datasheets/library/rechargeables/consumer/nimh/
nh15.pdf

Quoted message said:

Technical
support of a reputable battery manufacturer recently advised me that their
NiMH cells "can operate in discharge down to -30°C". I have successfully
used AA NiMH batteries at temperatures well below -20°C, but I have not
tried them with a GPS at such temperatures. [Easy to test in a deep-freeze,
I suppose].

Would need an external antenna though ;-)

--

Dominic Sexton
http://www.dscs.demon.co.uk/

Bitstring <[email hidden]>, from the wonderful person
Dominic Sexton <[email hidden]> said

Quoted message said:

In article <[email hidden]>, Alan
Law <[email hidden]> writes

Quoted message said:

"GSV Three Minds in a Can" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Neither LCD displays nor NiMH/Alkaline batteries much enjoy sub-zero
temps. For batteries, using Lithium, or Li-Ion, fixes the problem

//snipped//

Are there measurements to support that statement about NiMH cells?

I doubt it. Energizer's NiMH AA spec sheet says they operate down to
-20C.

For values of 'operate' which include a very large drop in both output
voltage and capacity. Trust me, NiMH at sub-zero temperatures are a
problem/issue, depending on how low a voltage your equipment will
operate from .. if you don't have a freezer, Google Is Your Friend.

--
GSV Three Minds in a Can
Outgoing Msgs are Turing Tested,and indistinguishable from human typing.

Dominic Sexton said:

In article <[email hidden]>, Steve
Crossley <[email hidden]> writes

Quoted message said:

Hello,
I am thing of buying a Garmin GPS, the basic one as I actually
enjoy compass work, but in heavy mist or a whiteout the wife might
like the reassurance of a GPS. Anyway I have read a review that
mentioned low temperature problems, has anyone any experience of this.

I have used GPS in the north of Russia in winter. The trick was to keep
it inside your clothing and just take it out when needed. The following
photo was taken at about -20C.

http://www.matley.co.uk/photo/eTrexRussia.jpg

My glove was off so that I could fiddle with the buttons to rename the
marked waypoint (~67N 57E). Once the photo was done the eTrex was inside
and the gloves on pretty quick.

Was that an integer confluence and is it up on confluence.org?

Nice and cold looking....

Richard Webb

In article <[email hidden]>, RJ Webb
<[email hidden]> writes

Quoted message said:

Dominic Sexton said:

In article <[email hidden]>, Steve
Crossley <[email hidden]> writes

Quoted message said:

Hello,
I am thing of buying a Garmin GPS, the basic one as I actually
enjoy compass work, but in heavy mist or a whiteout the wife might
like the reassurance of a GPS. Anyway I have read a review that
mentioned low temperature problems, has anyone any experience of this.

I have used GPS in the north of Russia in winter. The trick was to keep
it inside your clothing and just take it out when needed. The following
photo was taken at about -20C.

http://www.matley.co.uk/photo/eTrexRussia.jpg

My glove was off so that I could fiddle with the buttons to rename the
marked waypoint (~67N 57E). Once the photo was done the eTrex was inside
and the gloves on pretty quick.

Was that an integer confluence and is it up on confluence.org?

No, sadly it wasn't integer and there were no opportunities for
confluence hunting jollies on that job - it was an old rubbish tip!

Quoted message said:

Nice and cold looking....

Indeed it was. I particularly liked their deep freeze storing reindeer
carcasses - it was just an unheated hut on a sled!

A few more snaps:

The eTrex in action again - up against a Trimble 4800 (IIRC)
http://www.matley.co.uk/photo/eTrexWell.jpg

The local taxi
http://www.matley.co.uk/photo/CoCar.jpg

The one that got away
http://www.matley.co.uk/photo/Local.jpg

--

Dominic Sexton
http://www.dscs.demon.co.uk/

I have a basic Garmin, the Garmin 72. When the temperature drops to some
point (in the range 0 - 5 celsius) some of the keys work irregularly or
don't work. Whether this is due to the battery voltage dropping or not, I
don't know, though I suspect not because it happens with different sorts of
battery. Often it is the Goto button that is affected, which can be
extremely irritating.

Keeping the thing in a pocket isn't a good solution, because it is much more
likely to lose signal If it loses signal some buttons (such as Goto) are not
available.

Simon Stewart.

www.mountainviews.ie

"Steve Crossley" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Hello,
I am thing of buying a Garmin GPS, the basic one as I actually
enjoy compass work, but in heavy mist or a whiteout the wife might
like the reassurance of a GPS. Anyway I have read a review that
mentioned low temperature problems, has anyone any experience of this.

In article <[email hidden]>, Simon Stewart
<[email hidden]> writes

Quoted message said:

I have a basic Garmin, the Garmin 72. When the temperature drops to some
point (in the range 0 - 5 celsius) some of the keys work irregularly or
don't work.

Sounds like a faulty unit. I would contact Garmin about it if I were
you.

Quoted message said:

Whether this is due to the battery voltage dropping or not, I
don't know, though I suspect not because it happens with different sorts of
battery. Often it is the Goto button that is affected, which can be
extremely irritating.

Keeping the thing in a pocket isn't a good solution, because it is much more
likely to lose signal If it loses signal some buttons (such as Goto) are not
available.

Sure keeping it in a pocket is not ideal but it is a good way of keeping
it working when it gets a bit cold. You whip it out to refer to it and
then put it away for a while. That works well in all but the worst of
conditions where I humbly suggest a compass might be used to follow a
bearing given by the GPS.

--

Dominic Sexton
http://www.dscs.demon.co.uk/

Thanks for the replies. I think I will buy one as in all probability
it is going to work and if it does not jumping on it will warm me up,
and the smug satisfaction of my compass still working in those
temperatures will at least raise my morale.;-)
Steve Crossley

Steve Crossley said:

Thanks for the replies. I think I will buy one as in all probability
it is going to work and if it does not jumping on it will warm me up,
and the smug satisfaction of my compass still working in those
temperatures will at least raise my morale.;-)
Steve Crossley

Just to see what happened to a compass in the cold, I put an old Suunto
compass into the freezer at home. The liquid in the compass was still
liquid at about -25C. All that seems to have happened is the appearance
of a bubble in the liquid.

Perhaps I should try to simulate the Sahara using the microwave :-)

--
Dave McLaughlin

[censored] Sapiens Non Urinat In Ventum

In article <[email hidden]>, Dave Mclaughlin
<[email hidden]> writes

Quoted message said:

Steve Crossley said:

Thanks for the replies. I think I will buy one as in all probability
it is going to work and if it does not jumping on it will warm me up,
and the smug satisfaction of my compass still working in those
temperatures will at least raise my morale.;-)
Steve Crossley

Just to see what happened to a compass in the cold, I put an old Suunto
compass into the freezer at home. The liquid in the compass was still
liquid at about -25C. All that seems to have happened is the
appearance of a bubble in the liquid.

Perhaps I should try to simulate the Sahara using the microwave :-)

Don't zap it. They work fine in the Sahara :-)

--

Dominic Sexton
http://www.dscs.demon.co.uk/

In article <[email hidden]>, GSV Three Minds in a Can
<[email hidden]> writes

Quoted message said:

Bitstring <[email hidden]>, from the wonderful
person Dominic Sexton <[email hidden]> said

Quoted message said:

In article <[email hidden]>,
Alan Law <[email hidden]> writes

Quoted message said:

"GSV Three Minds in a Can" <[email hidden]> wrote in message
news:[email hidden]...
>
> Neither LCD displays nor NiMH/Alkaline batteries much enjoy sub-zero
> temps. For batteries, using Lithium, or Li-Ion, fixes the problem
>
>//snipped//
>

Are there measurements to support that statement about NiMH cells?

I doubt it. Energizer's NiMH AA spec sheet says they operate down to
-20C.

For values of 'operate' which include a very large drop in both output
voltage and capacity. Trust me,

I would rather trust my experience, thank you.

Quoted message said:

NiMH at sub-zero temperatures are a problem/issue, depending on how
low a voltage your equipment will operate from .. if you don't have a
freezer,

Well I have just taken a set of 4 1800mAh AA NiMh out of the freezer
(-24C according to the thermometer) which had been there for 5 hours. I
put the in my Canon A20 camera and took a few pictures with the LCD on
and the flash on without any indication of low battery.

I took them out of the camera and put them in my Garmin GPS12 (which has
a significantly lower current drain than the camera) and they are
happily powering that.

The batteries were last charged over a week ago but have not been used
since.

The battery indicator on the GPS was just over 3/4 (it is calibrated for
alkaline batteries) and the terminal voltage of each cell is ~1.3V.

Now they will obviously be warming up all the time since they were
removed from the freezer so I can't comment on their capacity at -20 ish
but this little experiment does show that the voltage is not a problem
even when rather cold - they were in the camera about a minute after
removing from the freezer as one of the batteries was stuck in the
holder.

Quoted message said:

Google Is Your Friend.

Indeed it is.

--

Dominic Sexton
http://www.dscs.demon.co.uk/

Alan Law said:

I have successfully used AA NiMH batteries at temperatures
well below -20°C, but I have not tried them with a GPS at such
temperatures. [Easy to test in a deep-freeze, I suppose].

I left my GPS in the freezer for a number of hours once, including
batteries. Temperature dropped to below -20 I think. GPS worked fine
when I tried it. LCD a bit faded, that's all.

Paul
--
http://www.wilderness-wales.co.uk
http://www.wildwales.fsnet.co.uk