Author Topic: DeLorme PN-40: Cold weather behavior  (Read 1383 times)

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Offline doc_kreipke

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DeLorme PN-40: Cold weather behavior
« on: December 07, 2010, 06:48:05 AM »
Dunno if this is characteristic of other GPS trackers; submitted FYI:

I was out hiking in about 25 degree weather with the PN-40 on the outside of my coat. After about a half hour, I noticed that the unit suddenly had lost its ability to zoom in closer than 1:96,000 (0.5 mile on the bar scale). Figuring that the cold might have something to do with it, I dropped the unit down inside my coat. After about 10 minutes of warming up, the unit was functioning normally again.

So, if your PN-40 acts up in the cold, a bit of warming might get it back on track again.
-K

Offline Siskiyou

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Re: DeLorme PN-40: Cold weather behavior
« Reply #1 on: December 07, 2010, 09:11:15 PM »


Unfortunately I have no experience with DeLorme gps units.  I have used a couple of their mapping products.  I believe the PN-40 is rated at -20 C which indicates to me that at 25˚ F the issue maybe with the state of your battery.  It would be interesting to hear what type of battery you are using and if it is the DeLorme Lithium the state of the charge at the start of your hike.

I like your warming the battery hint.

After a long career as a first responder using different generations of portable radios, and different batteries it is hard to beat good Alkaline AA batteries for dependability.  The down side is cost unless Uncle Sugar is buying. 

Cold temperatures are hard on batteries; battery type and age of the battery(s) are critical factors in the cold.  Reading some reviews on the PN-40 indicate that it might be a little harder on batteries then the PN-20.  Hopefully Lloyd from the world of cold and PN-20 will help us out here.

Nickel Metal Hydride batteries have been my buddy for years for day trips but when I things get serious I switch to Alkaline in my 76Cx.  I also backed off on the rechargeable because the size increased with more capacity.  The increased size damages battery cases and connectors.  I found that the higher capacity AA rechargeable will not fit inside a Mag-Lite.

When the weather turns cold and I am out hunting I switch from Nickel Metal Hydride batteries in my 76Cx to alkaline batteries.  Following the recommendations of other members I tried the Costco Kirkland AA Alkaline batteries.  They hold up great in the cold. I carry extra because they also fit my headlamp.  Many of the rechargeable batteries are too fat to fit some other devices.    The Lithium-Ion rechargeable battery that comes with the Rino 530HCx has a long field life.  Two of my hunting partners and I are using them and the hold up two or three days in cold weather.  I have an extra Lithium-Ion battery and AA battery pack for the Rino and have not had to use them.  Of course the batteries can be pulled from the battery pack in an emergency.

Minus 15 is just about the coldest temperatures I have hunted in since I have had a gps.  Temperatures in the 20’s are common and I have had no problems.   I recall being in very cold conditions one season above 7000 elevation, with snow and ice conditions.  At the time I was using an eTrex Legend.  I was carrying it in an enter shirt pocket and by accident keeping it warm.  It functioned without a problem. 

I recall reading an article in one of the outdoor magazines about a lost hunter in Idaho who had problems with the original yellow eTrex in a storm.  He claims the unit was not working part time.  That might have been caused by timber canopy.  If you recall the original eTrex did not have the high sensitivity receiver.  Cold temperatures might have impacted the batteries.  A third issue was the hunter was as familiar with the unit as he would have like. 

  I am sure that Dand, Lloyd and others are in colder temperatures then I and their experience in hard cold maybe different.  Glanceblamm in the upper Midwest gets hit by the cold and he is technically inclined.  It would be interesting to hear how he keeps operational in the cold.
There is a learning process to effectively using a gps.  Do not throw your compass and map away!

Boycott: San Francisco, L.A., Oakland, and City of Sacramento, CA.

Offline Glanceblamm

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Re: DeLorme PN-40: Cold weather behavior
« Reply #2 on: December 09, 2010, 05:04:45 AM »
That old Garmin 12 is not exactly battery friendly as you know and for the most part, it stays shutoff and in an inside coat pocket.

Got to make waypoints though and the trail head is a good place to start. After this it is a compass course and additional waypoints are created as terrain and points of interest dictate.

I have established routes of course and one thing worth mentioning is that your gps will work in simulator mode (no satellite connection) just as well as it does in real mode and the batterys will last forever.

Keep in mind that the gps needs to be oriented with a valid waypoint for this to happen. It also involves using the (Pan) and (mark) feature but this is a better subject for another thread titled emergency use or the like.



Offline Siskiyou

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Re: DeLorme PN-40: Cold weather behavior
« Reply #3 on: December 09, 2010, 06:08:27 AM »
Glanceblamm:  You have entered a part of the playing field that I have not spent little or no time in, the simulator mode.  The Garmin 12 is still a good unit but a battery eater.  Are there particular batteries you find best for your use?  A new topic on extending battery life and cold weather batteries would be welcome.  Batteries are kind of pricy and as I recall the Garmin 12 requires four? :o

What are the low temperatures you have operated in this hunting season?

Siskiyou
There is a learning process to effectively using a gps.  Do not throw your compass and map away!

Boycott: San Francisco, L.A., Oakland, and City of Sacramento, CA.

Offline Glanceblamm

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Re: DeLorme PN-40: Cold weather behavior
« Reply #4 on: December 10, 2010, 05:14:54 AM »
I give Duracell the edge on the batteries, Have been meaning to try some of the Energizer Lithiums but have not done that yet. I did put some of those Energizer Lithiums in an older digital camera that was notorious for eating AA's and got suprisingly good life out of them.

The rechargable types are not to be considered. They work well but even in a flashlight when they start to go, they do so very quickly as compared to the non rechargable types. Today, there is also a size issue with the
Rechargable like you were saying.

The battery life really is not too bad with my unit. I can keep it on 15 min here or up to 30 min there and that can go a long way as you know with the batterys bouncing back in between.

My cold weather usage for this year was on the Morning of Dec 3 but it was just 19 degree's. It was calm with star's visible overhead and that gps logged on so quickly that it almost knocked me off my feet as it recieved signal from multiple Satellites. The old garmin is working better than when it was new because of this and I hope that our Liberal Fed's will maintain what we have up there :-\

Those River bottoms with flood plains are pitch black in the early hours, it is kind of like viewing a lake in the dark with woods surrounding on all sides. My waypoints were set though and I lined them up just as carefully as one would line a Que-stick to a que ball with my blind being the pocket in this three waypoint setup. Brush and dead falls are obsticals of course and one does not want to go crashing around in the predawn. I had done my work well though and the Garmin
Guided me in just as sure as a localizer will guide a plane in on final as I hit my narrow path dead on.

Unrelated:
One could use the Gps to mark an entry and then use the likes of the (Bright Eyes) tack's that are highly reflective to a flashlight beam to lead the way. I have never done this because even before the GPS, I reckoned that they were for Pilgrims. My second thought is that if another hunter would see those tacks from afar, they would know your location and be able to cut off your trail upstream or downstream.

I guess that I am a purist by heart as I hated it when they commercialized deer hunting towards the late 80's. I can remember laughing until I cried when I saw a magazine picture of the small umbrella strapped to the tree above the hunters head as he was perched in his tree stand.

Safety: Safety is a high priority and one thing that I do is to get into the Blind\Stand while it is still full dark. Another thing that I still do is to let the small flashlight shine for abit before entering the woods. Sadly enough there are still those         Who would take a shot at a dark silly-wet in the false dawn or pre dawn. I hunt private property but one never knows if there would be a trespasser. If one would catch a deer slug, there is a very good chance that it would be all over.


Offline doc_kreipke

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Re: DeLorme PN-40: Cold weather behavior
« Reply #5 on: December 12, 2010, 06:23:44 PM »
The battery in the above scenario was indeed the DeLorme Li-ion rechargable. Started the hike at about 100% charge.

The Li-ion that came with my PN-40 will last about 4 hours in warm weather. But then, I run my screen backlight at nearly 100% illumination, always on.

I always pack at least a pair of Energizer Lithium cells as a back up.
-K

Offline Lloyd Smale

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Re: DeLorme PN-40: Cold weather behavior
« Reply #6 on: December 13, 2010, 12:42:03 AM »
I never was impressed with the rechargeable batterys supplied with mine. As a matter of fact i thought battery life was so poor that i called them and they sent me a new battery and charger. Even the new one was pretty lame. When i go into the woods i usually use a coventional litium battery or at least an alkaline battery. They work much better. I allways carry spares in my bag too. To be honest ive never seen where cold effected mine though but im not saying it couldnt. Most of the time when its cold mines next to my body in a pocket so i doubt if its ever really been done below zero.
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Offline Siskiyou

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Re: DeLorme PN-40: Cold weather behavior
« Reply #7 on: December 17, 2010, 06:20:56 PM »
I got back from a week of hunting in temperatures running from 20˚ to 42˚ and back down to 24˚.  I stayed at a friend’s place and it was normally a 40 minute drive to get into hunting country.  We would start out the morning watching the weather but once we were on the road I had my Garmin Rino on the weather to capture a more detailed forecast.

I am getting at what the drain or load on the unit was.  The power source was the Garmin rechargeable battery.  Before leaving the house the unit was in Track Mode, and I had the Map screen up.  My partner dropped me off at a high saddle and the plan was for me to work to higher elevation cut across the slope to a secondary ridge and drop to the bottom where I had ran into a bear last year.  

My partner drove a few miles to “J” hook to a ground stand where he could watch an old clearcut that was growing back.  I already had his ground blind as a waypoint in my gps.  I selected it as a Go To waypoint in my unit.  The plan being once I could look across the drainage and see the location I would switch waypoints.  The second waypoint is where I killed a buck a couple years ago.  This was the general location I spotted the bear last year.

The weather was real nasty with a cold rain, and then snow.  My glasses were fogging up along with my old binoculars.  The window for the hunt had opened quickly and I forgot that I had put my Leopold binoculars in my range bag and took a pair of fifty year old binoculars on the trip.  Visibility across the top was bad along with the clouds setting down on the peak at times.  This was a trip for a gps because at the top the topography split into three drainages.  I came close to dropping into the wrong drainage because of the limited visibility.    

To have dropped into the wrong drainage would have been a nasty event.  I have been sick for two months and not in the best of shape.  Going down in the wrong drainage would have dropped me about 1000 feet in elevation and I would have to regain 500 feet in elevation and walk a couple extra miles to make the pickup point.    I normally bring an extra Midland radio for my partner to use, but did not because he has a set of radios.  He did not have his radio with him.

When I got on the steep North Slope I had to cross an area that had been logged and there was a lot of slash on the ground covered with up to two feet of frozen snow.  I checked the Bearing Pointer on the Compass Page and the Dist To Dest box.  My partner had shot a buck on the lower slope below the ridge that I want to cross and worked down.    I had used my Nikon 800 rangefinder to determine the distance of his shot which was 266 yards.    Best estimate was the ridge from his location was 400 to 500 yards away from his stand.  

The snow had changed to a pounding rain and I cut across the snow covered slope to get into the timber so that I did not have to fight the snow on the ground.  The steep slope was slick and I took a couple of falls in the process.

Once in the timber I checked the Weaver scope on my 7MM Magnum and it was clear, and the covers went back on.  But it was the gps I kept checking every few hundred feet to make sure that I was on course because rain and low clouds, along with water covered glasses messed up my visibility.  

Once I was on the right ridge I glassed my hunting partners stand and realized that he was not there.  I knew I was running about an hour behind time.  It happen that we were in one of the few areas we hunt where there is limited cellphone coverage.  I got in under some heavy tree canopy to break the rain fall and gave him a call.  Normally we do not have our phones on when hunting.  He did not answer but returned my call in a few minutes.

When the rain intensified he had return to his pickup and moved to the location he was to pick me up.  I told him I was still an hour out.  I set my gps for the location I had killed the buck.  Going direct to the pickup point was not the best because of a rock face and steep terrain.  Going to the kill site put me below the steep terrain and from there I could work my way out to one of my old campsites where he was going to pick me up.  

My footwear was not the best for steep slopes but they were great for the snow rain mix.  I was wearing a twenty year old pair of LaCrosse Iceman Pacs.  My smokejumper 10 inch vibram boots were put away all week because of wet and cold conditions.  I took couple of falls, the first one was when I was on some open ground and a grape fruit size rock rolled under my foot and I hit the ground on my side keep my rifle up to protect it.   The other was crossing the icy frozen snow on the steep slope.   It was more of a slide then a fall.  I carry the Garmin Rino in a camera case because of its size and it did not suffer any damage.

I know my way back to the road but I selected my old campsite new to the road waypoint as a matter of practice and made it out to the pickup point.

After some lunch we head for the snow in the higher elevation hoping to pick up the track of a bear.  No such luck.  The gps keep recording our track and was a dependable source of location information along with Weather Radio updates.  I used the same battery a second day before charging it.  The charge level at that time had dropped to 32%.

A little Catch-22 the next morning when I started up the gps in the pickup the back light did not come on and I could not see the screen enough to work the menu options to return the backlight.  It did not matter when the sun came up.  

I must have lost some brain cells during the illness because I could not remember how to reset the light.  Later on I remember and had the backlight working the next morning when we started out.  There must have been some sort of fault that caused it to shut down.

After the battery was charged I replaced it with an extra rechargeable.  With the Garmin gps units the Altimeter and the electronic Compass need to be recalibrated after a battery change.

A gps is a handy tool when the fog sets in, or the clouds come down on the mountain tops.  It is not too difficult to become disorientated; especially when the body becomes fatigued from exertion and cold.

The next day the temperature held around 24˚ and there was a lot of battery left at the end of the day.

I have been interested in the DeLorme units but they have not been in the budget.  The PN-60 with Spot just might be the thing for old guys.

http://www.delorme.com/

There is a learning process to effectively using a gps.  Do not throw your compass and map away!

Boycott: San Francisco, L.A., Oakland, and City of Sacramento, CA.

Offline Dand

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Re: DeLorme PN-40: Cold weather behavior
« Reply #8 on: January 05, 2011, 10:37:34 PM »
I'm still pretty much a novice on GPS compared to many and especially Sisk here. But sometimes I operate in 0 to -20 F. Cold is real tough on batteries and the old Garmin Legend I had.  I wear a many pocket vest under my parka or whatever outer gear I have. I keep small survival stuff in it including AA batteries for flashlight, GPS, camera and AAA batteries for my LED headlamp. I keep an upper pocket open to tuck the GPS in when not in use. The GPS is on a string around my neck most of the time.  I don't leave mine running for any length of time to hoard batteries.

I too like the Kirkland Alkaline AAs - they work well and last quite a while. The first ones I had were fantastic quite a few years ago.  Then there was a period where they didn't seem so long lived. Lately they've been ok.

I also often carry the Energizer Lithiums for back ups as I've been told they are supposed to last better in cold.  I haven't used them a lot but so far I'm not convinced they work that much better for their cost.

Now I have the Garmin Legend HCX after losing the old one last winter.  This unit seems better on batteries. I left it on quite a bit this fall during moose season when temps ranged from high 30s to a few days even into high 60s. Not much of a temperature challenge but this unit does better than the old Legend.

I have been using some rechargeable batteries in my small Nikon camera - Sanyo Eneloops from Amazon. They are by far the best recharging batteries I've found. I think I had a pair in my camera for 4-6 months, fair bit of use and some of it in 10 to 35 degree weather.  I can't recall if I have tried them in the new GPS.

Some trappers up here rig GPS mounts on their snogos and even  duct warm air onto the units. Even with a 12v power system from the snogo, at -20 to -40 or lower that some of these guys operate, they need to keep the GPS warm.

At any rate, in cold weather I try to keep my GPS and batteries warm and only pull it out to spot check. Also at some of these temps it can be hard to keep fingers warm enough to operate the units.

Rex from OTZ in Kotzebue or Sourdough from North Pole probably would have some sage advice - they can be found on the Hunting in Alaska Forum. I think they get out more often and in much tougher conditions than I do.


NRA Life

liberal Justice Hugo Black said, and I quote: "There are 'absolutes' in our Bill of Rights, and they were put there on purpose by men who knew what words meant and meant their prohibitions to be 'absolutes.'" End quote. From a recent article by Wayne LaPierre NRA

Offline Siskiyou

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Re: DeLorme PN-40: Cold weather behavior
« Reply #9 on: January 06, 2011, 07:16:07 AM »
   

“After the battery was charged I replaced it with an extra rechargeable.  With the Garmin gps units the Altimeter and the electronic Compass need to be recalibrated after a battery change.”

I need to clarify my statement for the user not familiar you Garmin Gps units.  The units with electronic compass and altimeter need calibrating after a battery change.   

The models that do not have the electronic compass and altimeter obtain their elevation and compass direction from satellite impute.  If I was to buy a companion Rino I would go for the 520HCx which lacks the electronic compass and altimeter.  I feel the satellite impute is more than adequate for most uses.  Do not get fixated on USGS Topo map elevations.  A 20 foot error is allowable.  With modern technology the elevation of mountain peaks are changing.  You can read about this fire lookout at this link, a short read.

 http://www.peakbagging.com/CALookoutPhotos/Schonchin.pdf


Dand a great post I read you imput closely you live in a harsher condition than I.
There is a learning process to effectively using a gps.  Do not throw your compass and map away!

Boycott: San Francisco, L.A., Oakland, and City of Sacramento, CA.

Offline Lloyd Smale

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Re: DeLorme PN-40: Cold weather behavior
« Reply #10 on: January 07, 2011, 12:19:13 AM »
it helps a whole lot to only use the backlight feature when its needed and keep it turned off in the daytime. Mine also seems to have better battery life if left on topo maps rather then on arieals or sat imagery. Could be it takes more power to boot up those maps.
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Offline Glanceblamm

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Re: DeLorme PN-40: Cold weather behavior
« Reply #11 on: January 07, 2011, 04:10:09 AM »
Siskiyou, excellent blow by blow account as said in reply #7

Dand, My old Sony Cyber-shot camera would eat up a set of AA batterys right before your eyes!...I bought one of the $50 enclosed case batterys with charger and it would easily go a week recording up to 100 pictures. That battery lasted 4 yrs and expired when the first grandson was born. I grabbed the "dead" camera for the two hr trip and purchased some Energizer Lithiums at a Walgreens while on the road, they did the job just fine + more. I have not had a set of them in the GPS yet but my usage is "spot on" or Simulator for established routes so the standard grade of batt hold up well.

Lloyd, I guess that I was dissapointed to hear of the preformance of your rechargable. My thoughts were of that $50 rechargable for the old camera and how well it worked, no comparison between it verse the AA as said.
Perhaps the GPS is just a higher drainage device? Only other thing that I can think of is Color Display, When we bought a daughter the first of the portable color game machines, it would wipe out the batterys quickly.