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Thread: Take Me To GPS School

  1. #76
    Senior Member CaptCaper's Avatar
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    Quote Originally Posted by Dharma Bum View Post
    This is all very very helpful. Thanks for the comments on battery life and how to maximize.
    Also some of the Garmin models like the Montana have settings in the menu for which battery type your using. So make sure that jives with what your using.
    Eveloop Pros are again the Cat's Meow.

  2. #77
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by CaptCaper View Post
    Also some of the Garmin models like the Montana have settings in the menu for which battery type your using. So make sure that jives with what your using.
    Eveloop Pros are again the Cat's Meow.
    Actually the battery setting only affects the battery meter--it has no effect on the operation of the GPS.

    The GPSes have a regulator that accepts a range of voltages and when the input voltage drops down to 2V (for a two cell GPS) it turns the GPS off. At this point, essentially all of the energy in the batteries has been consumed.

    Doug

  3. #78
    Senior Member CaptCaper's Avatar
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    I know about the meter. And the wrong setting could be giving him false readings on battery life.. I am trying to narrow down why he said only "a few hours"..so far he hasn't said much on what batteries he uses etc. His head is probably spinning from the new gps. Ha.
    If I can get all day running my Montana's with Glonass/Waas, in the winter and an amplified external antenna (draws more current as well) he should be about to do the same.

  4. #79
    Senior Member hikerbrian's Avatar
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    Quote Originally Posted by DayTrip View Post
    I have a Garmin GPSmap 62s and I regularly get 10-12 hours out of rechargeable batteries (closer to 8 hours in extreme cold if I leave clipped to pack versus putting in a pocket). I also believe my settings are more or less "out of the box". I've been using my rechargeable batteries now for 2 full years and there seems to have been minimal loss of capacity. My headlamp uses the same AA size (which I did on purpose) so I carry a back up set of batteries that can be used with either or depending on what is in needed. Unless you are going on extremely long or multi-day hikes you should get a day out of most GPS devices.
    Thanks DayTrip. That's useful info. I rarely do anything other than at least an overnight (2-day), so for now I've stuck with disposable cells. My understanding is you get more life out of the disposable cells, though I haven't done the direct experiment. Still, I'm sure others will find this info useful.
    Sure. Why not.

  5. #80
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by CaptCaper View Post
    I know about the meter. And the wrong setting could be giving him false readings on battery life.. I am trying to narrow down why he said only "a few hours"..so far he hasn't said much on what batteries he uses etc.
    Hopefully he means until the GPS turns itself off. (This is certainly what I mean.) However it is important to know that the battery setting will have no effect on the actual lifetime.

    His head is probably spinning from the new gps. Ha.
    Certainly possible. I suspect that many have such a reaction from their first GPS. They are wonderful but complicated little beasts...

    If I can get all day running my Montana's with Glonass/Waas, in the winter and an amplified external antenna (draws more current as well) he should be about to do the same.
    I have had to change my NiMH batteries in my 60CSx on some 18+ hour BC ski trips but a fully charged set of NiMHs lasts for a "normal" day. (I generally use fully charged NiMH batts.)

    I measured the additional current draw of an external antenna at 15mA on a 60CS but 0mA on a 60CSx. (Zero additional draw is possible if using an external antenna shuts off an amplifier for the internal antenna.)

    I published some battery lifetime measurements for 2 (different) 60CSxes: http://www.vftt.org/forums/showthrea...tery-lifetimes

    Doug

  6. #81
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by hikerbrian View Post
    Thanks DayTrip. That's useful info. I rarely do anything other than at least an overnight (2-day), so for now I've stuck with disposable cells. My understanding is you get more life out of the disposable cells, though I haven't done the direct experiment. Still, I'm sure others will find this info useful.
    Actually all three types of cells (NiMH, alkaline, and lithium primary (non-rechargeable)) have relatively similar capacities (typ 2000-2500 mAh for AA cells and 700-800 mAh for AAA) at room temperature.

    See my measured room temp NiMH battery lifetimes in http://www.vftt.org/forums/showthrea...tery-lifetimes

    Doug

  7. #82
    Senior Member hikerbrian's Avatar
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    Quote Originally Posted by DougPaul View Post
    Actually all three types of cells (NiMH, alkaline, and lithium primary (non-rechargeable)) have relatively similar capacities (typ 2000-2500 mAh for AA cells and 700-800 mAh for AAA) at room temperature.

    See my measured room temp NiMH battery lifetimes in http://www.vftt.org/forums/showthrea...tery-lifetimes

    Doug
    Total capacity isn't the relevant parameter when we're talking about cold weather use though, right? My limited reading tells me Li primaries (non-rechargeable) provide useable current (i.e. effectively operate your GPS) for the longest period of time when it's, say, -10 to +10 F. As an aside, I feel like I've read every one of your posts on this subject, and I still seem to learn something new each time... So thanks in advance for any clarification!

    Edit: Here is a decent, short FAQ on the different types of AA and AAA batteries for anyone who is interested.
    Last edited by hikerbrian; 04-13-2016 at 10:29 PM.
    Sure. Why not.

  8. #83
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by hikerbrian View Post
    Total capacity isn't the relevant parameter when we're talking about cold weather use though, right? My limited reading tells me Li primaries (non-rechargeable) provide useable current (i.e. effectively operate your GPS) for the longest period of time when it's, say, -10 to +10 F. As an aside, I feel like I've read every one of your posts on this subject, and I still seem to learn something new each time... So thanks in advance for any clarification!
    As the temp drops, alkalines degrade the fastest, NiMH at an intermediate rate, and lithium (primary cells) the slowest. The exact (effective) capacity depends on the battery, the load, and the temp so I can't give you any specific numbers. Note that the cold doesn't actually drain energy from the cells, it simply reduces the rate (power) at which energy can be drawn from the cells. Thus the cutoff will be reached sooner in the cold, but the battery will likely become useful again if it is warmed back up (and kept warm) while using it.

    Some headlamps designed for very cold use feature external battery packs so the batteries can be kept warm next to one's body.

    Edit: Here is a decent, short FAQ on the different types of AA and AAA batteries for anyone who is interested.
    I like http://batteryuniversity.com/. A (big) bit longer, but it also covers a lot more of the details...

    Doug

  9. #84
    Senior Member CaptCaper's Avatar
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    The units like Montana and Oregon are higher drawing devices then many household or other devices... that will take down a disposable battery faster despite it may have higher amp hours. .. better off with a high end rechargeable for these newer color mapping photo types. Especially because they are used out doors were temps are not high here in New England this time of year. Seems part of his problem are the disposables he said he uses.
    I use Garmins OEM rechargeable on my Montana's 600 and 610T with no issues hiking like I posted above in temps to 5 deg so far. I've used the Montana in temps much lower and to 20 below but was on a power mount on my snowmobile.
    I'm going to get a Monterra as well...well see how that does. ha...

  10. #85
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by CaptCaper View Post
    The units like Montana and Oregon are higher drawing devices then many household or other devices... that will take down a disposable battery faster despite it may have higher amp hours. .. better off with a high end rechargeable for these newer color mapping photo types. Especially because they are used out doors were temps are not high here in New England this time of year. Seems part of his problem are the disposables he said he uses.
    I use Garmins OEM rechargeable on my Montana's 600 and 610T with no issues hiking like I posted above in temps to 5 deg so far. I've used the Montana in temps much lower and to 20 below but was on a power mount on my snowmobile.
    I classify GPSes as medium drain devices: I've measured 70--200 mA* depending on what is turned on and the model. (I've also seen hardware upgrades within a model between early and late versions.) I believe Garmin rates their units with alkalines unless the unit comes with a battery.
    * Well within the capabilities of typical AA cells of any of the three technologies at room temp--a bright flashlight/headlamp can draw 500 mA or more.

    NiMH's are probably good to somewhere around 0F and lithiums to somewhere below -20F in GPSes. My 60CSx is rated 5F--158F (-15C--70C). Touch screens may also be a limiting factor at the temp extremes.

    FWIW--I generally use Eneloop 2000 mAh cells. Higher capacity cells often have a shorter service life.

    Doug

  11. #86
    Senior Member CaptCaper's Avatar
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    Hopefully some here might learn from these postings..The guy who called it a toy never came back. He'll never know what he's missing.

    It might be time to reconsider medium drain classifications with cameras with flash, bright screens like the Oregon and Montana has......plus factor in outside temps used by most hikers. On a side not I didn't say High Drain. I said higher draining. Also the higher capacity cells are good to 800 uses or so.. I don't think I'll or anyone else will use them for even half that use. In any event you can get the Pro's for $15...for 4... cheap enough for the higher capacity. Price of a Big Mac meal with desert.

    The Oregon only takes 2 AA's but still has a camera and flash. But I bet it draws near the voltage of my 3 battery Montana's. Another reason I'm into a Montana and might be going with a Monterra totally. Time will tell. No external antenna jack so it better give me good signal for my style of usage on it.

    I've had no issues running my Montana touch screen on the snowmobile handle bar mounted at 14 below or so... never..except my fingers getting cold if I have my gloves removed.

    So as expected tests or guidelines usually don't fair to the real world and ones use. As as such I don't bother to really pay much attention to them and haven't bothered to read them from non professional sources especially.

    Same with batteries...every use is different. Mounted near body? inside a pouch? kept running? But it's good to know if your screen isn't responding..put it in your pants for a while and see if that helps. No high tech test there. Ha.
    Last edited by CaptCaper; 04-14-2016 at 11:47 AM.

  12. #87
    Senior Member DougPaul's Avatar
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    Quote Originally Posted by CaptCaper View Post
    The Oregon only takes 2 AA's but still has a camera and flash.
    Cameras, particularly with flash, tend to have a low continuous power draw with high power for short periods when the shutter is fired. (Plus, of course, the steady draw of the GPS in this case.) Alkalines fare poorly in this kind of service on pure cameras and may not be the best choice on a GPS with camera. (However, NiMH and lithium cells do well in this service.)

    But I bet it draws near the voltage of my 3 battery Montana's.
    (I suspect that you mean current or power rather than voltage.)

    * for the Oregon:
    2cells * 2000mAh = 4000mAh
    4000/mAh / 16h = 250mA
    250mA * 3V = 750mW

    * for the Montana:
    3cells * 2000mAh = 6000mAh
    6000mAh / 22h = ~273mA
    273mA * 4.5V = 1229mW

    So the currents are similar, but the Montana draws ~50% more power.

    Another reason I'm into a Montana and might be going with a Monterra totally. Time will tell. No external antenna jack so it better give me good signal for my style of usage on it.
    I normally carry my 60CSx in the top of my pack using the internal antenna and get fairly good looking tracks. (Certainly good enough for hiking purposes.) I only use an external antenna (mounted on top of my hat) when intentionally mapping a trail with the goal of getting a best-quality track.

    Somehow, I suspect this is getting a bit orthogonal to the needs of the OP...

    Doug
    Last edited by DougPaul; 04-14-2016 at 03:26 PM.

  13. #88
    Senior Member hikerbrian's Avatar
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    Quote Originally Posted by DougPaul View Post
    As the temp drops, alkalines degrade the fastest, NiMH at an intermediate rate, and lithium (primary cells) the slowest.
    Warning: not terribly relevant questions follow; unlikely to be interesting unless you're either an EE or chemist. You've been warned.

    DP: To humor my inner (and sometimes outer) nerd, do you know why this is true? I'm thinking the problem is actually with the electrolyte solution - with alkaline and NiMH batteries, that electrolyte is usually aqueous potassium hydroxide, which gets quite viscous when cold and, I'm guessing, restricts the movement of ions through it. Lithium primaries, on the other hand, have an organic electrolyte, whose properties perhaps don't change as much when it's cold? What do you think? I don't think the relative rates of the redox reactions at the annode and cathode would change that much with temperature; the rates should all change by roughly the same amount.

    Or does electrolyte have nothing to do with it, and it's just the shape of the discharge curve? Li and NiMH batteries have a relatively square discharge curve, while alkalines have a constant discharge curve. So if you decrease the performance of each of them by the same amount, they'll all work about the same at the beginning, but alkalines will soon not provide enough voltage to do what you need, while the others are likely to maintain 'enough' voltage to drive your device. What do you think?
    Sure. Why not.

  14. #89
    Senior Member CaptCaper's Avatar
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    Quote Originally Posted by DougPaul View Post
    Cameras, particularly with flash, tend to have a low continuous power draw with high power for short periods when the shutter is fired. (Plus, of course, the steady draw of the GPS in this case.) Alkalines fare poorly in this kind of service on pure cameras and may not be the best choice on a GPS with camera. (However, NiMH and lithium cells do well in this service.)
    That is what I said above of course..Maybe you didn't understand me.


    Quote Originally Posted by DougPaul View Post
    (I suspect that you mean current or power rather than voltage.)

    * for the Oregon:
    2cells * 2000mAh = 4000mAh
    4000/mAh / 16h = 250mA
    250mA * 3V = 750mW

    * for the Montana:
    3cells * 2000mAh = 6000mAh
    6000mAh / 22h = ~273mA
    273mA * 4.5V = 1229mW

    So the currents are similar, but the Montana draws ~50% more power.
    The Montana only gets 16hrs on the OEM battery. But 22 hrs for AA's. It doesn't state what batteries the Oregon is rated by. Check Garmins site at this link you'll see the difference. Hard to believe that the Oregon gets 50% less so your figures may be off not knowing which batteries are used in the guideline. The screen is smaller so that may be but 50%.. Again I wouldn't etch that summary or formula you did in stone without a side by side test. I never take one guys word on anything as fact.

    http://https://buy.garmin.com/en-US/...Product=113548


    I normally carry my 60CSx in the top of my pack using the internal antenna and get fairly good looking tracks. (Certainly good enough for hiking purposes.) I only use an external antenna (mounted on top of my hat) when intentionally mapping a trail with the goal of getting a best-quality track.

    Well see...I hope the Monterra will do the tracking very close to what I'm getting now with 610T Glonass/GPS WAAS ON settings and dual external antenna custom made for me by a company
    Last edited by CaptCaper; 04-14-2016 at 04:10 PM.

  15. #90
    Senior Member CaptCaper's Avatar
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    They don't all start out the same. Alk's will allow a stronger supply at first over the others but fade out faster basically. That's all I need to know. Layman's terms are like the Rabbit and the Hare story.
    Lot's of info on the web...But what we all agree on is Alk's are only good for throw away's...in GPS use anyway given outdoor temps and constant running.

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