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Hi everyone,
I'm climbing Ben Nevis at the end of March and have been looking for what I need to adjust my compass bearings to for getting off the summit (if the weather takes a turn for the worse) but can't seem to find a definitive answer. Can someone help me out please?
thanks!
I'm climbing Ben Nevis at the end of March and have been looking for what I need to adjust my compass bearings to for getting off the summit (if the weather takes a turn for the worse) but can't seem to find a definitive answer. Can someone help me out please?
thanks!
In reply to Rorymchenry:
If you mean declination (i.e. the difference between magnetic north and grid north) it's printed on the OS Map. Its essentially 0 in the UK at the minute.
If you're just being too lazy to take a bearing from the mpa yourself...
If you mean declination (i.e. the difference between magnetic north and grid north) it's printed on the OS Map. Its essentially 0 in the UK at the minute.
If you're just being too lazy to take a bearing from the mpa yourself...
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In reply to Rorymchenry:
Declination in that area is currently 3.5 degrees west. That means if you take a bearing on the map, you add three degrees before following it.
Edit: Here's a useful map showing declination around the world, you can zoom in on the UK:
http://maps.ngdc.noaa.gov/viewers/historical_declination/
Make sure you select 2015. Note that the lines on that map don't point north, they are lines of equal declination, if you click on one it tells you at the bottom what the declination is. It varies from 0.5 degrees west in Kent to 4.5 degrees in the Outer Hebrides.
Declination in that area is currently 3.5 degrees west. That means if you take a bearing on the map, you add three degrees before following it.
Edit: Here's a useful map showing declination around the world, you can zoom in on the UK:
http://maps.ngdc.noaa.gov/viewers/historical_declination/
Make sure you select 2015. Note that the lines on that map don't point north, they are lines of equal declination, if you click on one it tells you at the bottom what the declination is. It varies from 0.5 degrees west in Kent to 4.5 degrees in the Outer Hebrides.
Post edited at 11:08
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In reply to Rorymchenry:
Although being able to use a compass in a white out with dangerous terrain about is a handy skill to have, it's always going to be inaccurate often more so the worse the conditions. Personally I prefer a GPS with maps on it for getting me out of places like that and map and compass as a back up. Its also normally faster.
Although being able to use a compass in a white out with dangerous terrain about is a handy skill to have, it's always going to be inaccurate often more so the worse the conditions. Personally I prefer a GPS with maps on it for getting me out of places like that and map and compass as a back up. Its also normally faster.
Post edited at 10:59
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In reply to CurlyStevo:
Burn the heretic
By the way, I agree. Although my partner and I did have fun in a Caringorm blizzard the other day performing several hours of leapfrogging
> Although being able to use a compass in a white out with dangerous terrain about is a handy skill to have, it's always going to be inaccurate often more so the worse the conditions. Personally I prefer a GPS with maps on it for getting me out of places like that and map and compass as a back up. Its also normally faster.
Burn the heretic
By the way, I agree. Although my partner and I did have fun in a Caringorm blizzard the other day performing several hours of leapfrogging
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In reply to BnB:
Yeah its a fair bit slower (maybe half as quick) and still not as accurate the map way. I guess I'm at an advantage to most Scotland newbies in that I know my way about many of the hills - to some extent anyway. recently I got myself from the top of hells lum area to fiachaill a choirie chais in a whiteout looking at the gps twice and the compass maybe twice more There were some vague footprints to follow at times and I generally knew which way to go so which way to turn when they diverged....
Yeah its a fair bit slower (maybe half as quick) and still not as accurate the map way. I guess I'm at an advantage to most Scotland newbies in that I know my way about many of the hills - to some extent anyway. recently I got myself from the top of hells lum area to fiachaill a choirie chais in a whiteout looking at the gps twice and the compass maybe twice more There were some vague footprints to follow at times and I generally knew which way to go so which way to turn when they diverged....
Post edited at 11:16
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In reply to Rorymchenry:
Awesome thanks, so the first grid bearing from the summit cairn of 231 degrees should be 234.5?
Will take gps as well but good to know the old fashioned way too!
Awesome thanks, so the first grid bearing from the summit cairn of 231 degrees should be 234.5?
Will take gps as well but good to know the old fashioned way too!
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In reply to Jack B:
That gives you the angle between True North and Magnetic North. For use with OS maps, you want the the angle between Grid North and Magnetic North: http://www.geomag.bgs.ac.uk/data_service/models_compass/gma_calc.html
For Ben Nevis this is currently about 1 degree west, which is scarcely worth bothering with.
> Declination in that area is currently 3.5 degrees west. That means if you take a bearing on the map, you add three degrees before following it.
> Edit: Here's a useful map showing declination around the world, you can zoom in on the UK:
That gives you the angle between True North and Magnetic North. For use with OS maps, you want the the angle between Grid North and Magnetic North: http://www.geomag.bgs.ac.uk/data_service/models_compass/gma_calc.html
For Ben Nevis this is currently about 1 degree west, which is scarcely worth bothering with.
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In reply to Mark Bull:
So I actually needn't worry about making any adjustments for walking 150m....?
So I actually needn't worry about making any adjustments for walking 150m....?
In reply to Eeyore:
Its a fair point, I guess it's nice to have something independent and with a different failure mechanism to electric stuff. Its also cheaper and I find my GPS screen can be a little small (maybe I should upgrade to a bigger screened one). Your call I guess.
Its a fair point, I guess it's nice to have something independent and with a different failure mechanism to electric stuff. Its also cheaper and I find my GPS screen can be a little small (maybe I should upgrade to a bigger screened one). Your call I guess.
Post edited at 12:07
In reply to Rorymchenry:
The error over 150m would be about 2.5m. You would be doing well if your pacing error was less than that!
The error over 150m would be about 2.5m. You would be doing well if your pacing error was less than that!
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In reply to Rorymchenry:
Not being a Ninja navigator I'd worry more about my ability to follow the bearing and measure the 150m with reasonable accuracy than whether I should make a 1 degree (0.3%) correction to the bearing. Which is why I would take a GPS.
> So I actually needn't worry about making any adjustments for walking 150m....?
Not being a Ninja navigator I'd worry more about my ability to follow the bearing and measure the 150m with reasonable accuracy than whether I should make a 1 degree (0.3%) correction to the bearing. Which is why I would take a GPS.
In reply to CurlyStevo:
I use ViewRanger on iphone 6 and it's fantastic for those situations, although like you I'm pretty familiar with much of the terrain I frequent (Cuillin, NW Highlands, Lakes, N Wales, Norries).
Before anyone chips in and asks what I do if the battery runs out, I'll quickly observe that the battery lasts more than 8 days in airplane mode with occasional peeks at a screen and in 30 years of mobile phone use I've never yet had a battery issue on a hill.
I've killed a phone with water once but that's no greater than the count of lost compasses (which I always have to hand as well). It's good to know how to use both.
I use ViewRanger on iphone 6 and it's fantastic for those situations, although like you I'm pretty familiar with much of the terrain I frequent (Cuillin, NW Highlands, Lakes, N Wales, Norries).
Before anyone chips in and asks what I do if the battery runs out, I'll quickly observe that the battery lasts more than 8 days in airplane mode with occasional peeks at a screen and in 30 years of mobile phone use I've never yet had a battery issue on a hill.
I've killed a phone with water once but that's no greater than the count of lost compasses (which I always have to hand as well). It's good to know how to use both.
In reply to Rorymchenry:
Sounds like it.
You have had 3 different opinions of the current variation, 3.5 ; 0 and 1, neither of them significant over the short distance as has been pointed out. .
The lack of agreement on here of what the current fifference is, is the only thing that would interest me, not the actual figures, which are at worst not a big issue.
" (It varies from 0.5 degrees West in Kent to 4.5 degrees in the Outer Hebrides.)"
> So I actually needn't worry about making any adjustments for walking 150m....?
Sounds like it.
You have had 3 different opinions of the current variation, 3.5 ; 0 and 1, neither of them significant over the short distance as has been pointed out. .
The lack of agreement on here of what the current fifference is, is the only thing that would interest me, not the actual figures, which are at worst not a big issue.
" (It varies from 0.5 degrees West in Kent to 4.5 degrees in the Outer Hebrides.)"
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In reply to CurlyStevo:
The only time I've tried to use a GPS in bad conditions was on the Ben a few years ago. Not quite white out but usual high wind / cold/crap visibility stuff. The battery died in the cold and although we did have map and compass, we hadn't got the navigation 'wired' (bearings already set on compass, map in the rucsac etc) and to compound the difficulty we had already started following the GPS before it died so we didn't know where we had to start navigation from !
I think we would have got by but luckily we just about saw a couple of far better prepared winter walkers and managed to latch on behind them.
I'm sure technology has moved on a bit since then !
The only time I've tried to use a GPS in bad conditions was on the Ben a few years ago. Not quite white out but usual high wind / cold/crap visibility stuff. The battery died in the cold and although we did have map and compass, we hadn't got the navigation 'wired' (bearings already set on compass, map in the rucsac etc) and to compound the difficulty we had already started following the GPS before it died so we didn't know where we had to start navigation from !
I think we would have got by but luckily we just about saw a couple of far better prepared winter walkers and managed to latch on behind them.
I'm sure technology has moved on a bit since then !
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In reply to BnB:
I had the full battery on my iPhone 5s die as soon as I turned it on due to cold last time I was out in winter, and otherwise the battery is still really good on that phone. I use eneloop in my GPS as they can handle cold temps. I'm pretty sure the phone would have started working again just fine if I'd warmed it in my for half an hour but for how long out of my pocket is debateable. Also I find touch screens stop working properly in fowl cold conditions and if it was raining hard it could also be an issue. Although the screen is small and the machine is a bit old my garmin (with all the uk maps) is a lot more bombproof.
I had the full battery on my iPhone 5s die as soon as I turned it on due to cold last time I was out in winter, and otherwise the battery is still really good on that phone. I use eneloop in my GPS as they can handle cold temps. I'm pretty sure the phone would have started working again just fine if I'd warmed it in my for half an hour but for how long out of my pocket is debateable. Also I find touch screens stop working properly in fowl cold conditions and if it was raining hard it could also be an issue. Although the screen is small and the machine is a bit old my garmin (with all the uk maps) is a lot more bombproof.
Post edited at 14:17
In reply to CurlyStevo:
Never had that happen to me so perhaps it's where you keep your phone. Mine never leaves the breast pocket o fmy midlayer except in use, so that may be the trick.
Never had that happen to me so perhaps it's where you keep your phone. Mine never leaves the breast pocket o fmy midlayer except in use, so that may be the trick.
In reply to Rorymchenry:
Here you go, have fun.
http://www.geomag.bgs.ac.uk/data_service/models_compass/gma_calc.html
Here you go, have fun.
http://www.geomag.bgs.ac.uk/data_service/models_compass/gma_calc.html
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In reply to Rorymchenry:
I use an ortlieb mapcase with an iphone 4S. You can scroll the screen through the plastic.
A fairly recent ios update included a battery save mode which is very effective. I also switch the Sim card off.. After navigating in a whiteout on Hellvelyn I still had 85% charge at the end of the day.
I use an ortlieb mapcase with an iphone 4S. You can scroll the screen through the plastic.
A fairly recent ios update included a battery save mode which is very effective. I also switch the Sim card off.. After navigating in a whiteout on Hellvelyn I still had 85% charge at the end of the day.
In reply to ianstevens:
What he said.
> If you mean declination (i.e. the difference between magnetic north and grid north) it's printed on the OS Map. Its essentially 0 in the UK at the minute.
What he said.
In reply to Rorymchenry:
Head towards the smell of chips for 3 rope lengths then turn right and follow the yellow snow and red bull cans till you get to the zig zags
Head towards the smell of chips for 3 rope lengths then turn right and follow the yellow snow and red bull cans till you get to the zig zags
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In reply to BnB:
Lost of reports online of iPhone 6's shutting down after a few minutes in very cold temps. Also from experience touch screens can stop working right in cold temps with cold hands
Lost of reports online of iPhone 6's shutting down after a few minutes in very cold temps. Also from experience touch screens can stop working right in cold temps with cold hands
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In reply to CurlyStevo:
Doesn't have to be particularly cold. Got my iphone 5 out whilst fellrunning last weekend ( mebe -7c in the wind ?) and it turned itself off after c.1 minute out of my bag..
Doesn't have to be particularly cold. Got my iphone 5 out whilst fellrunning last weekend ( mebe -7c in the wind ?) and it turned itself off after c.1 minute out of my bag..
In reply to CurlyStevo:
Agreed.
Mine is sensitive to cold. Recently had my iphone in my jacket pocket whilst cycling in temps only of around zero. Phone indicated low battery needing recharging, but within 10 mins back in the house it was showing 46% battery.
I would never trust a modern phone (should say though that an iphone is my only experience of a modern phone in extreme cold as I have a prehistoric basic phone for emergency calls in the sac) if it is necessary to be useable in outdoor conditions. On the other hand my GPS has never stopped working due to cold and I've used it down to -19 C. Yes you may have to replace batteries sooner but that is easy done.
Agreed.
Mine is sensitive to cold. Recently had my iphone in my jacket pocket whilst cycling in temps only of around zero. Phone indicated low battery needing recharging, but within 10 mins back in the house it was showing 46% battery.
I would never trust a modern phone (should say though that an iphone is my only experience of a modern phone in extreme cold as I have a prehistoric basic phone for emergency calls in the sac) if it is necessary to be useable in outdoor conditions. On the other hand my GPS has never stopped working due to cold and I've used it down to -19 C. Yes you may have to replace batteries sooner but that is easy done.
In reply to Climbing Pieman:
Apple do not advise operating temps for iphone below freezing.
I've had phone GPS let me down on a few occasions over several phone models with different failure modes and one was nearly quite serious. Also the GPS in many phones is not as accurate as a proper GPS and tends to rely somewhat on phone signal. Its fine for a sunny day walk in a non serious environment but beyond that I'm not convinced (unless you know for a fact your phone doesn't suffer from these sort of issues - ie it has a proper GPS, the input works well with cold hands in a cold environment / the wet, and the battery doesn't suddenly report dead when it shouldn't in the cold)
Apple do not advise operating temps for iphone below freezing.
I've had phone GPS let me down on a few occasions over several phone models with different failure modes and one was nearly quite serious. Also the GPS in many phones is not as accurate as a proper GPS and tends to rely somewhat on phone signal. Its fine for a sunny day walk in a non serious environment but beyond that I'm not convinced (unless you know for a fact your phone doesn't suffer from these sort of issues - ie it has a proper GPS, the input works well with cold hands in a cold environment / the wet, and the battery doesn't suddenly report dead when it shouldn't in the cold)
Post edited at 11:28
In reply to Climbing Pieman:
regarding batteries - have your tried eneloop nimh? they are brilliant in the cold and seem to function nearly as well as the warm. They are a lot better than hybrio that claim to use similar tech.
regarding batteries - have your tried eneloop nimh? they are brilliant in the cold and seem to function nearly as well as the warm. They are a lot better than hybrio that claim to use similar tech.
In reply to CurlyStevo:
Yes, used in GPS. No problem experienced with the hybrio ones though (maybe temps were warmer, can't remember!).
Yes, used in GPS. No problem experienced with the hybrio ones though (maybe temps were warmer, can't remember!).
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In reply to Climbing Pieman:
I have both.
The hybrio don't last as well in the cold or hold charge nearly as well in the draw (I charge mine all at the same time if I test what's remaining a few months later the hybrios are normally nearly flat when the eneloop are nearly full)
Actually I don't find hybrio that much (any ?) better than a descent nimh (but without claims of the fancy tech). On a fully charged battery in normal conditions and used fairly quickly they are all (normal nimh / hybrio / eneloop) much of a muchness.
I have both.
The hybrio don't last as well in the cold or hold charge nearly as well in the draw (I charge mine all at the same time if I test what's remaining a few months later the hybrios are normally nearly flat when the eneloop are nearly full)
Actually I don't find hybrio that much (any ?) better than a descent nimh (but without claims of the fancy tech). On a fully charged battery in normal conditions and used fairly quickly they are all (normal nimh / hybrio / eneloop) much of a muchness.
Post edited at 12:23
In reply to wilkie14c:
Prize for best reply so far. . .
Alternatively follow the line of discarded GPSs and iPhones to your eternal doom?
Prize for best reply so far. . .
> Head towards the smell of chips for 3 rope lengths then turn right and follow the yellow snow and red bull cans till you get to the zig zags
Alternatively follow the line of discarded GPSs and iPhones to your eternal doom?
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In reply to lummox:
My iphone crashed out after less than 1 imin on Ben Lomond on Sunday.
(And it was to take a photo , I don't ever use it for navigation on the hills, only in the car . )
> Doesn't have to be particularly cold. Got my iphone 5 out whilst fellrunning last weekend ( mebe -7c in the wind ?) and it turned itself off after c.1 minute out of my bag..
My iphone crashed out after less than 1 imin on Ben Lomond on Sunday.
(And it was to take a photo , I don't ever use it for navigation on the hills, only in the car . )
In reply to paraffin:
Haha true story!
ok on a serious note, this leaflet is usually available to pick up around fort William but here it is in web form.
Well worth printing and laminating it and pitting it in your sack.
http://www.mcofs.org.uk/ben-nevis-navigation.asp
Haha true story!
ok on a serious note, this leaflet is usually available to pick up around fort William but here it is in web form.
Well worth printing and laminating it and pitting it in your sack.
http://www.mcofs.org.uk/ben-nevis-navigation.asp
Post edited at 13:15
In reply to Rorymchenry:
Rechargeable lithium ion batteries do not generally like being used below freezing (and should never be charged below freezing). It is bad for the chemistry and bad things can happen inside them. Some batteries may have protection circuits that include a thermometer to avoid battery damage (good for the battery, bad if you need to navigate in a whiteout).
Non-rechargeable lithiums are, I believe, suitable for very cold use. I don't know about NiMH (or NiCADs although I'm not even sure you can get them any more).
Keep your phone next to your body to keep it warm (I have a waterproof pouch thing with a neck lanyard) and it probably has a much better chance of working.
Alkalines are generally just crap at any temperature for high loads and zinc chloride are so crap to be entirely irrelevant.
Rechargeable lithium ion batteries do not generally like being used below freezing (and should never be charged below freezing). It is bad for the chemistry and bad things can happen inside them. Some batteries may have protection circuits that include a thermometer to avoid battery damage (good for the battery, bad if you need to navigate in a whiteout).
Non-rechargeable lithiums are, I believe, suitable for very cold use. I don't know about NiMH (or NiCADs although I'm not even sure you can get them any more).
Keep your phone next to your body to keep it warm (I have a waterproof pouch thing with a neck lanyard) and it probably has a much better chance of working.
Alkalines are generally just crap at any temperature for high loads and zinc chloride are so crap to be entirely irrelevant.
Post edited at 15:29
In reply to andrewmcleod:
normal nimh are not so good in the cold they discharge much faster for one. Eneloop nimh are acually rated down to pretty low temps the pro go down to -20!
normal nimh are not so good in the cold they discharge much faster for one. Eneloop nimh are acually rated down to pretty low temps the pro go down to -20!
In reply to Rorymchenry:
From the OS 1:25,000 map from top trip point walk on grid bearing of 231 deg for 150M then follow a grid bearing of 281 deg to clear the plateau & gain the path.
Magnetic north is 5deg west of grid north for 1994 & decreasing by 1/2deg every 3yrs.
So 2016 =1deg west to add to grid bearing.
As for people being surprised at their phone freezing...LOL....do they bother the check the operating spec for them? obviously not, as most will only operate at 0c (ipad mini =0C) with some down to -10C, the old original Yellow Garmin Etrex GPS goes down to -10C & I have seen those freeze in a CG blizzard after being taken out of pocket for 2 mins to get a "fix"!
New Garmin Etrex 10, 20, 30 GPS operate down to -20C & with a set of Energizer Lithium AA batteries will outperform a set of eneloop rechargeable. Lithium AA's are what my Petzl headtorch takes & because they are so lightweight I can take a couple of full spare sets & tend to buy in bulk from Amazon (not market place).
My phone is an old Samsung B2100, which is military spec & I have used at -25C no problems!!!
Technology has moved on folks & costs have come down, time to modernise!!
From the OS 1:25,000 map from top trip point walk on grid bearing of 231 deg for 150M then follow a grid bearing of 281 deg to clear the plateau & gain the path.
Magnetic north is 5deg west of grid north for 1994 & decreasing by 1/2deg every 3yrs.
So 2016 =1deg west to add to grid bearing.
As for people being surprised at their phone freezing...LOL....do they bother the check the operating spec for them? obviously not, as most will only operate at 0c (ipad mini =0C) with some down to -10C, the old original Yellow Garmin Etrex GPS goes down to -10C & I have seen those freeze in a CG blizzard after being taken out of pocket for 2 mins to get a "fix"!
New Garmin Etrex 10, 20, 30 GPS operate down to -20C & with a set of Energizer Lithium AA batteries will outperform a set of eneloop rechargeable. Lithium AA's are what my Petzl headtorch takes & because they are so lightweight I can take a couple of full spare sets & tend to buy in bulk from Amazon (not market place).
My phone is an old Samsung B2100, which is military spec & I have used at -25C no problems!!!
Technology has moved on folks & costs have come down, time to modernise!!
Post edited at 17:38
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In reply to Snowdave:
Although Lithium may seem superior I personally think for most winter day trip uses they are vastly inferior to eneloop (especially the pro version but I've used all since the first model in winter very successfully). With Eneloop you have the advantage you can fully charge them before you go out giving you more power than a partly used lithium battery, which you are often unsure about how much charge is left in it. You also have the advantage that eneloops are much more environmentally friendly than lithium batteries and also cheaper.
I've used eneloops extensively in a head torch without a separate battery compartment for around a decade now. This has been through several epics and dark winter approaches and desents in the UK and Europe in temperatures as low as -20. I have never needed to replace freshly charged batteries on the hill during use. I use my GPS less but I've never come close to wearing freshly charged eneloop batteries down in that.
I'm wondering if you've ever actually used eneloops in winter or you have just gone down the lithium route as you assumed they were better (I've used both BTW).
Although Lithium may seem superior I personally think for most winter day trip uses they are vastly inferior to eneloop (especially the pro version but I've used all since the first model in winter very successfully). With Eneloop you have the advantage you can fully charge them before you go out giving you more power than a partly used lithium battery, which you are often unsure about how much charge is left in it. You also have the advantage that eneloops are much more environmentally friendly than lithium batteries and also cheaper.
I've used eneloops extensively in a head torch without a separate battery compartment for around a decade now. This has been through several epics and dark winter approaches and desents in the UK and Europe in temperatures as low as -20. I have never needed to replace freshly charged batteries on the hill during use. I use my GPS less but I've never come close to wearing freshly charged eneloop batteries down in that.
I'm wondering if you've ever actually used eneloops in winter or you have just gone down the lithium route as you assumed they were better (I've used both BTW).
Post edited at 18:23
In reply to CurlyStevo:
>> I'm wondering if you've ever actually used eneloops in winter or you have just gone down the lithium route as you assumed they were better (I've used both BTW).
No I haven't used eneloops, the Pro batteries are about £10/pk of 4 & a proper individual channel charger is at least £32 to get the most out of the batteries. So about £52 just to start for me.
The lithium's go down to -40C, the eneloops to -20C with reduced operational time (as the stated operational time is at +20C) , both figures/facts from manufacturers own website.
Also the lithium's are lighter, plus I carry two full sets as spare, as my headtorch & GPS take the same AA batteries & can use lithium's.
I don't bother looking at the environment side as I currently do way more than the average UK person & when China, India & USA act as green as us in the UK then I will do more.
>> I'm wondering if you've ever actually used eneloops in winter or you have just gone down the lithium route as you assumed they were better (I've used both BTW).
No I haven't used eneloops, the Pro batteries are about £10/pk of 4 & a proper individual channel charger is at least £32 to get the most out of the batteries. So about £52 just to start for me.
The lithium's go down to -40C, the eneloops to -20C with reduced operational time (as the stated operational time is at +20C) , both figures/facts from manufacturers own website.
Also the lithium's are lighter, plus I carry two full sets as spare, as my headtorch & GPS take the same AA batteries & can use lithium's.
I don't bother looking at the environment side as I currently do way more than the average UK person & when China, India & USA act as green as us in the UK then I will do more.
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In reply to Snowdave:
>Magnetic north is 5deg west of grid north for 1994 & decreasing by 1/2deg every 3yrs. So 2016 =1deg west to add to grid bearing
Not sure it always works like that extrapolating over a long time period as the rate of change is not linear.
However, the British Geological Survey, which according to the OS website is the source of this data for the OS, does give 1 degree west for July 2015.
http://www.geomag.bgs.ac.uk/data_service/models_compass/gma_calc.html
Martin
>Magnetic north is 5deg west of grid north for 1994 & decreasing by 1/2deg every 3yrs. So 2016 =1deg west to add to grid bearing
Not sure it always works like that extrapolating over a long time period as the rate of change is not linear.
However, the British Geological Survey, which according to the OS website is the source of this data for the OS, does give 1 degree west for July 2015.
http://www.geomag.bgs.ac.uk/data_service/models_compass/gma_calc.html
Martin
In reply to Snowdave:
I suspect the average person in China or India has substantially lower carbon emissions than the average UK person, and a significant fraction of China and India's carbon emissions is making stuff for us which really ought to be counted as our emissions anyway...
> I don't bother looking at the environment side as I currently do way more than the average UK person & when China, India & USA act as green as us in the UK then I will do more.
I suspect the average person in China or India has substantially lower carbon emissions than the average UK person, and a significant fraction of China and India's carbon emissions is making stuff for us which really ought to be counted as our emissions anyway...
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In reply to Snowdave:
the pro eneloops will almost definitely still function under -20. I have used the normal ones rated to -10 to -20 before with no issues. Plus I've never gone much below that temp wise so I don't see the need. As mentioned the discharge rate in cold temps is still very very good, I've not noticed a difference from using them at higher temps, although I'm sure there is one.
I already have a charger for my other batteries (remotes etc) as I care about the environment and in the long run its MUCH cheaper.
Eneloop pro are 7.99 at maplin and lithium are about 4 quid so you are saving money from the 3rd time you change the batteries.
All the other advantages I mentioned also hold.
Maybe it would be worth trying something before knocking it next time then you can speak from experience.
the pro eneloops will almost definitely still function under -20. I have used the normal ones rated to -10 to -20 before with no issues. Plus I've never gone much below that temp wise so I don't see the need. As mentioned the discharge rate in cold temps is still very very good, I've not noticed a difference from using them at higher temps, although I'm sure there is one.
I already have a charger for my other batteries (remotes etc) as I care about the environment and in the long run its MUCH cheaper.
Eneloop pro are 7.99 at maplin and lithium are about 4 quid so you are saving money from the 3rd time you change the batteries.
All the other advantages I mentioned also hold.
Maybe it would be worth trying something before knocking it next time then you can speak from experience.
Post edited at 12:12
In reply to andrewmcleod:
Its hardly a justification is it - everyone else is f*cking up the planet so I may as well do the same. Sure we all have an impact and we are going to prioritise some of our life above lowering that impact but where you can lower your impact you may as well.
Its not just the energy it takes to create these things anyway is it, its the environmental impact of creating and destroying them. I wonder if Snowdave disposes of his batteries properly or just lobs them in to the dustbin and has an even greater negative impact.
> I suspect the average person in China or India has substantially lower carbon emissions than the average UK person, and a significant fraction of China and India's carbon emissions is making stuff for us which really ought to be counted as our emissions anyway...
Its hardly a justification is it - everyone else is f*cking up the planet so I may as well do the same. Sure we all have an impact and we are going to prioritise some of our life above lowering that impact but where you can lower your impact you may as well.
Its not just the energy it takes to create these things anyway is it, its the environmental impact of creating and destroying them. I wonder if Snowdave disposes of his batteries properly or just lobs them in to the dustbin and has an even greater negative impact.
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In reply to CurlyStevo:
Don't see any point in really going for it "green" if even with the day to day stuff I am & the UK is, way ahead of those said countries as basically any more green that we in UK do will have very little effect in the big picture because those other counties pollute so much! Drop of rain in an ocean springs to mind. If you want to get all greener than thou on other people that's your problem.
Battery recycling, along with light bulbs, etc etc I have been doing for as long as the council place has been taking the stuff which is over 15yrs, nearer 20yrs.
I have walked to work for the past 15yrs & have not been on a plane over that period of time either, & for the past 20yrs my home has had advanced weather compensating demand dependent heating controls, so I'm pretty green thinking, ..anything else you want to falsely accuse me off???
Back OT, in winter up here I have had -25C no problems on CG in winter with wind chill, kills most head torches, so lithium's I have used, I have had friends use normal eneloops in winter with poor results compared to lithium's, so have stayed away from rechargeables as they were the "best". The pro's MIGHT be ok, but need to invest £££ & it's the quote of "reduced operating time at -20C compered to +20C" (from their website) which is bothering me as that's a 40C difference & that's a lot for a battery which can affect the operating time. I'll stick with the lithium's for now, until they improve the cold weather capabilities & weight of the rechargeable to match that of lithium.
> Its hardly a justification is it - everyone else is f*cking up the planet so I may as well do the same. Sure we all have an impact and we are going to prioritise some of our life above lowering that impact but where you can lower your impact you may as well.
Don't see any point in really going for it "green" if even with the day to day stuff I am & the UK is, way ahead of those said countries as basically any more green that we in UK do will have very little effect in the big picture because those other counties pollute so much! Drop of rain in an ocean springs to mind. If you want to get all greener than thou on other people that's your problem.
> I wonder if Snowdave disposes of his batteries properly or just lobs them in to the dustbin and has an even greater negative impact.
Battery recycling, along with light bulbs, etc etc I have been doing for as long as the council place has been taking the stuff which is over 15yrs, nearer 20yrs.
I have walked to work for the past 15yrs & have not been on a plane over that period of time either, & for the past 20yrs my home has had advanced weather compensating demand dependent heating controls, so I'm pretty green thinking, ..anything else you want to falsely accuse me off???
Back OT, in winter up here I have had -25C no problems on CG in winter with wind chill, kills most head torches, so lithium's I have used, I have had friends use normal eneloops in winter with poor results compared to lithium's, so have stayed away from rechargeables as they were the "best". The pro's MIGHT be ok, but need to invest £££ & it's the quote of "reduced operating time at -20C compered to +20C" (from their website) which is bothering me as that's a 40C difference & that's a lot for a battery which can affect the operating time. I'll stick with the lithium's for now, until they improve the cold weather capabilities & weight of the rechargeable to match that of lithium.
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In reply to Snowdave:
We are all on this planet together mate, its not about comparing countries. Just because you have walked a lot or don't own a charger doesn't discount the argument that Nimh batteries are more environmentally friendly and cheaper to run over the long haul..
"Back OT, in winter up here I have had -25C no problems on CG in winter with wind chill"
You seem to have misunderstood the concept of wind chill. It's comparing the affect of temperature and wind on the human body not on head torch batteries where it would have no effect, only temperature is important. Also munro level temperatures never get anything like as low as those of the deep glens. The record low temperature at night in Scotland is -27.2 at Braemar but it wouldn't have been anything like that cold at the level on the munro tops and would have been more like -10 to -15 as the cold air drops out of the hills in those conditions (cold air sinks under warmer air). Anyway like I said I've used the eneloops (the old ones and the new pro ones) extensively in cold conditions in the UK and also in the Alps and they work brilliantly so your observations are unfounded and based only on incorrect assumptions and not use in the field.
If you have a google you'll see lots of people are raving about the eneloops in very cold conditions and plenty of positive freezer tests have been done (-22) even on the non pro batteries. Apparently they store charger for longer in the freezer and still work well cold.
eg"However, some independent tests suggest that the Eneloops do work better in cold weather. For instance, see the following German forum: http://www.rc-network.de/forum/showthread.php?t=59430&page=2. In their tests at -24£C, the Eneloops discharged at 2A put out about 1400mAh."
That's something like 75% of the usable charge of a warm OLD non pro eneloop. I wonder how well the pro's would perform
We are all on this planet together mate, its not about comparing countries. Just because you have walked a lot or don't own a charger doesn't discount the argument that Nimh batteries are more environmentally friendly and cheaper to run over the long haul..
"Back OT, in winter up here I have had -25C no problems on CG in winter with wind chill"
You seem to have misunderstood the concept of wind chill. It's comparing the affect of temperature and wind on the human body not on head torch batteries where it would have no effect, only temperature is important. Also munro level temperatures never get anything like as low as those of the deep glens. The record low temperature at night in Scotland is -27.2 at Braemar but it wouldn't have been anything like that cold at the level on the munro tops and would have been more like -10 to -15 as the cold air drops out of the hills in those conditions (cold air sinks under warmer air). Anyway like I said I've used the eneloops (the old ones and the new pro ones) extensively in cold conditions in the UK and also in the Alps and they work brilliantly so your observations are unfounded and based only on incorrect assumptions and not use in the field.
If you have a google you'll see lots of people are raving about the eneloops in very cold conditions and plenty of positive freezer tests have been done (-22) even on the non pro batteries. Apparently they store charger for longer in the freezer and still work well cold.
eg"However, some independent tests suggest that the Eneloops do work better in cold weather. For instance, see the following German forum: http://www.rc-network.de/forum/showthread.php?t=59430&page=2. In their tests at -24£C, the Eneloops discharged at 2A put out about 1400mAh."
That's something like 75% of the usable charge of a warm OLD non pro eneloop. I wonder how well the pro's would perform
Post edited at 17:00
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In reply to CurlyStevo:
I don't disagree on enviro reasons, or for those who have lots of use for them in warmer temps they are good, but for those of us who use it as main back up & are not out every week & tend to be out in winter then I PREFER 100% reliability.
Er you don't understand, wind chill WILL affect machinery if the said machine radiates heat & is at a higher temperature than the ambient air, LEDs get hot on the circuit board & so do the batteries, therefore a head torch worn on a helmet with the batteries in the unit itself WILL be exposed to windchill!! That's why electronics & batteries get affected & don't work in winter conditions unless thick insulating cases etc!!
From the Alaska science forum:-
http://www2.gi.alaska.edu/ScienceForum/ASF5/529.html
That may be so but why then do the manufactures clearly state the -20C with reduced operational time compared to the quoted +20C operational time then?? When the manufactures clearly state that they are supposedly that good, then maybe I'll reconsider them for my winter use headtorch & GPS.
> We are all on this planet together mate, its not about comparing countries. Just because you have walked a lot or don't own a charger doesn't discount the argument that Nimh batteries are more environmentally friendly and cheaper to run over the long haul..
I don't disagree on enviro reasons, or for those who have lots of use for them in warmer temps they are good, but for those of us who use it as main back up & are not out every week & tend to be out in winter then I PREFER 100% reliability.
> You seem to have misunderstood the concept of wind chill. It's comparing the affect of temperature and wind on the human body not on head torch batteries where it would have no effect, only temperature is important.
Er you don't understand, wind chill WILL affect machinery if the said machine radiates heat & is at a higher temperature than the ambient air, LEDs get hot on the circuit board & so do the batteries, therefore a head torch worn on a helmet with the batteries in the unit itself WILL be exposed to windchill!! That's why electronics & batteries get affected & don't work in winter conditions unless thick insulating cases etc!!
From the Alaska science forum:-
http://www2.gi.alaska.edu/ScienceForum/ASF5/529.html
> If you have a google you'll see lots of people are raving about the eneloops in very cold conditions and plenty of positive freezer tests have been done (-22) even on the non pro batteries. Apparently they store charger for longer in the freezer and still work well cold.eg"However, some independent tests suggest that the Eneloops do work better in cold weather. For instance, see the following German forum: http://www.rc-network.de/forum/showthread.php?t=59430&page=2. In their tests at -24£C, the Eneloops discharged at 2A put out about 1400mAh."
That may be so but why then do the manufactures clearly state the -20C with reduced operational time compared to the quoted +20C operational time then?? When the manufactures clearly state that they are supposedly that good, then maybe I'll reconsider them for my winter use headtorch & GPS.
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In reply to Snowdave:
Unfortunately you also seem to have misunderstood the web site that you linked to (along with the basic concept of windchill). I quote from it "So the answer to the question is yes. Wind chill does affect machines, but only if they are at a temperature above that of the surrounding air. ". The clue here is "but only if they are at a temperature above that of the surrounding air ". Seeing as it never gets below -15 air temperature at munro level and extremely rarely below -10 head torch batteries for uk hill use do not need to handle air temps lower than -15 because the effect they describe on machinery can not take it lower than ambient air temperature.
IMO it's also a misuse of the term windchill to say it can affect machinery as it's supposed to be defined as "Wind-chill or windchill, (popularly wind chill factor) is the perceived decrease in air temperature felt by the body on exposed skin due to the flow of air." Yes the wind can cool machinery faster but that is not the windchill factor as defined! https://en.wikipedia.org/wiki/Wind_chill
It doesn't really matter what the manufacturer states in terms of min temperature for eneloops, they don't qualify that and they are probably just stating the temperature at which much below that the maximum amps they can output or effective charge is getting significantly lower (perhaps 70 - 80% of the normal performance is their cut off). I've never needed them in temps lower than -20 if I needed them to work a lot lower than that I might use lithium. Anyway people have tested them to -24 as stated and they worked really well. There's a guy on here that has used them to around -35 degrees http://www.camtrapper.com/viewtopic.php?p=81320 . Have a google about (or even better try them) I think you'll be genuinely surprised how well they work in the cold.
Good luck attempting to think up some new theories regarding your incorrect assumptions based on never having used eneloops in the UK. I however have used them extensively in the UK winter for a decade and KNOW for a fact they are brilliant and 100% reliable. My head torch is a bog standard tikka XP and the batteries are kept in the torch housing not in separate 'warmer' pouch or under some extra insulation - as there is no need!
Unless you are replacing your lithiums well before they run out the eneloops are superior as I never need to replace them on the hill as they are always fully charged before I go out - as well as being cheaper and more environmentally friendly. My charger and batteries paid for them selves many many moons ago - YMMV.
Unfortunately you also seem to have misunderstood the web site that you linked to (along with the basic concept of windchill). I quote from it "So the answer to the question is yes. Wind chill does affect machines, but only if they are at a temperature above that of the surrounding air. ". The clue here is "but only if they are at a temperature above that of the surrounding air ". Seeing as it never gets below -15 air temperature at munro level and extremely rarely below -10 head torch batteries for uk hill use do not need to handle air temps lower than -15 because the effect they describe on machinery can not take it lower than ambient air temperature.
IMO it's also a misuse of the term windchill to say it can affect machinery as it's supposed to be defined as "Wind-chill or windchill, (popularly wind chill factor) is the perceived decrease in air temperature felt by the body on exposed skin due to the flow of air." Yes the wind can cool machinery faster but that is not the windchill factor as defined! https://en.wikipedia.org/wiki/Wind_chill
It doesn't really matter what the manufacturer states in terms of min temperature for eneloops, they don't qualify that and they are probably just stating the temperature at which much below that the maximum amps they can output or effective charge is getting significantly lower (perhaps 70 - 80% of the normal performance is their cut off). I've never needed them in temps lower than -20 if I needed them to work a lot lower than that I might use lithium. Anyway people have tested them to -24 as stated and they worked really well. There's a guy on here that has used them to around -35 degrees http://www.camtrapper.com/viewtopic.php?p=81320 . Have a google about (or even better try them) I think you'll be genuinely surprised how well they work in the cold.
Good luck attempting to think up some new theories regarding your incorrect assumptions based on never having used eneloops in the UK. I however have used them extensively in the UK winter for a decade and KNOW for a fact they are brilliant and 100% reliable. My head torch is a bog standard tikka XP and the batteries are kept in the torch housing not in separate 'warmer' pouch or under some extra insulation - as there is no need!
Unless you are replacing your lithiums well before they run out the eneloops are superior as I never need to replace them on the hill as they are always fully charged before I go out - as well as being cheaper and more environmentally friendly. My charger and batteries paid for them selves many many moons ago - YMMV.
Post edited at 18:31
In reply to CurlyStevo:
I think I know about temperature inversions, & cold valleys & warmer tops, & believe me some of the cold winters the tops have been way lower than you would think, but because there is no weather station there no one can record it! Anyway most of the places around here & where my mates live have recorded -18 to -27 most winters in the villages, (just google UK lowest temps & it comes up with most of the villages around Cairngorm National park).
>
>> Good luck attempting to think up some new theories regarding your incorrect assumptions based on never having used eneloops in the UK.
Never denied I have not used them, I even said they are best for certain situations but not for me, & going on the product info supplied by the manufacturers themselves. You just seem to be going on a "bash anyone who does not use eneloops trip".
Whatever...I'll do my "green" bit by not wasting any more electricity in replying to you.
> Unfortunately you also seem to have misunderstood The clue here is "but only if they are at a temperature above that of the surrounding air ". Seeing as it never gets below -15 air temperature at munro level and extremely rarely below -10 head torch batteries for uk hill use do not need to handle air temps lower than -15 because the effect they describe on machinery can not take it lower than ambient air temperature.
I think I know about temperature inversions, & cold valleys & warmer tops, & believe me some of the cold winters the tops have been way lower than you would think, but because there is no weather station there no one can record it! Anyway most of the places around here & where my mates live have recorded -18 to -27 most winters in the villages, (just google UK lowest temps & it comes up with most of the villages around Cairngorm National park).
>
>> Good luck attempting to think up some new theories regarding your incorrect assumptions based on never having used eneloops in the UK.
Never denied I have not used them, I even said they are best for certain situations but not for me, & going on the product info supplied by the manufacturers themselves. You just seem to be going on a "bash anyone who does not use eneloops trip".
> Unless you are replacing your lithiums well before they run out the eneloops are superior as I never need to replace them on the hill as they are always fully charged before I go out - as well as being cheaper and more environmentally friendly. My charger and batteries paid for them selves many many moons ago - YMMV.
Whatever...I'll do my "green" bit by not wasting any more electricity in replying to you.
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In reply to Snowdave: and CurlyStevo.
Fascinating though it may be, aw this technical battery banter (ie ambient/wind chill temp effects on said batteries), for the layman, might no be such a big deal. For the uninitiated, do either lithiums or eneloops adversely effect the magnetic variation on Ben Nevis?
Fascinating though it may be, aw this technical battery banter (ie ambient/wind chill temp effects on said batteries), for the layman, might no be such a big deal. For the uninitiated, do either lithiums or eneloops adversely effect the magnetic variation on Ben Nevis?
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In reply to Snowdave:
There are in fact two weather stations in Scotland that record all the weather data. One on top of Cairngorm and the other on top of Aonach Mor. The cairngorm one has records going back years and its all here in black and white for you to view. You'll see what I said about it very rarely falling below -10 and never below -15 on tops of the higher hills is a fact.
http://cairngormweather.eps.hw.ac.uk/archive.htm
There are in fact two weather stations in Scotland that record all the weather data. One on top of Cairngorm and the other on top of Aonach Mor. The cairngorm one has records going back years and its all here in black and white for you to view. You'll see what I said about it very rarely falling below -10 and never below -15 on tops of the higher hills is a fact.
http://cairngormweather.eps.hw.ac.uk/archive.htm
Post edited at 01:40
In reply to Joak:
No. But I wouldn't be surprised if having a phone in the chest pocket of your jacket did.
May as well talk about batteries as magnetic variation anyway because no mortal has a hope of walking on a bearing to an accuracy of 1 degree over a boulder field on the top of a mountain in bad weather.
> Fascinating though it may be, aw this technical battery banter (ie ambient/wind chill temp effects on said batteries), for the layman, might no be such a big deal. For the uninitiated, do either lithiums or eneloops adversely effect the magnetic variation on Ben Nevis?
No. But I wouldn't be surprised if having a phone in the chest pocket of your jacket did.
May as well talk about batteries as magnetic variation anyway because no mortal has a hope of walking on a bearing to an accuracy of 1 degree over a boulder field on the top of a mountain in bad weather.
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In reply to tom_in_edinburgh:
Or indeed the price of fish....
>
> May as well talk about batteries as magnetic variation anyway...
> May as well talk about batteries as magnetic variation anyway...
Or indeed the price of fish....
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In reply to Rorymchenry:
So the answer was zero.
But after 4 days of discussion I am now lost and I don't know my NiCad from my Eneloop. HEEELLLLPPPPPH!!!!
So the answer was zero.
But after 4 days of discussion I am now lost and I don't know my NiCad from my Eneloop. HEEELLLLPPPPPH!!!!
1
In reply to paraffin:
yeah, who bothers with a few degrees here or there on the summit of ben nevis in a storm..
yeah, who bothers with a few degrees here or there on the summit of ben nevis in a storm..
In reply to paraffin:
Haha yes well thanks everyone for all the additional advice!
At least maps don't have batteries...
Haha yes well thanks everyone for all the additional advice!
At least maps don't have batteries...
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In reply to wilkie14c:
sounds like 3leggeddog has left one his installations as a convenient waymarker. good on ya dogging boy. b*gger recyling when you can make "art". Its like waiting for the next banksy. a bit.
> Head towards the smell of chips for 3 rope lengths then turn right and follow the yellow snow and red bull cans till you get to the zig zags
sounds like 3leggeddog has left one his installations as a convenient waymarker. good on ya dogging boy. b*gger recyling when you can make "art". Its like waiting for the next banksy. a bit.
In reply to Rorymchenry:
They don't got flat , they just blow away
> Haha yes well thanks everyone for all the additional advice!
> At least maps don't have batteries...
They don't got flat , they just blow away
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