Take Me To GPS School

[DougPaul]

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/showthread.php?38355-60CSx-battery-lifetimes

Doug

 

[hikerbrian]

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/showthread.php?38355-60CSx-battery-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.

 

[DougPaul]

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

 

[CaptCaper]

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...

 

[DougPaul]

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

 

[CaptCaper]

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.

 

[DougPaul]

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

 

[hikerbrian]

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?

 

[CaptCaper]

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.

(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/US/catalog/product/compareResult.ep?compareProduct=523677&compareProduct=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

 

[CaptCaper]

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.

 

[DougPaul]

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?

Sorry, all I know is that the different chemistries slow down differently as the temp drops, not why.

There are some curves of performance of lithium cells vs temp in http://data.energizer.com/PDFs/lithiuml91l92_appman.pdf

Doug

 

[DougPaul]

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.

I assumed the alkaline battery lifetimes in both cases. Since the Oregon spec didn't specify, I assumed that the lifetimes were similar for all battery types.

Lighten up--it was just a back-of-the-envelope estimate using whatever data I could get from Garmin's website.

http://https://buy.garmin.com/en-US/US/catalog/product/compareResult.ep?compareProduct=523677&compareProduct=113548

Bad url.

IMO, this tangent is of little value. Time to terminate it.

Doug

 

[DougPaul]

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.

Actually, lithium primary cells can start out at ~1.8V* compared to the ~1.55V of alkalines (and ~1.40V for NiMH). This 1.8V initial voltage could damage a number of earlier electronic devices (eg LED headlamps) and caused some GPSes to sense an overvoltage and shut down. (The 1.8V start didn't last long and the cure was to run the battery in a tolerant device for a short time to reduce the voltage to ~1.5V.) Most modern outdoor electronics now tolerates the 1.8V start.
* See http://data.energizer.com/PDFs/l91.pdf pg 2, "Application Tests", "CD/GAMES"

The 3 different technologies have different discharge curves:
* Lithium can start at up to 1.8v, then rapidly settles to ~1.5V and stays there until near complete discharge whereupon the voltage drops rapidly. (A mostly rectangular discharge curve.)
* NiMH has a similar mostly rectangular discharge curve starting at a bit above 1.35V, then staying ~1.30--1.35V until exhaustion.
* Alkaline starts around 1.55V and tapers throughout its use.

The battery voltage is important, but so is the internal impedance. (The internal impedance causes the output terminal voltage to drop under load and ultimately limits the maximum current. As the battery is discharged, the voltage generally drops while the internal impedance increases.) Alkalines have a higher internal impedance than either NiMH or lithium and thus don't do as well under higher loads regardless of the open-circuit (zero current) voltage.

Doug

 

[hikerbrian]

Sorry, all I know is that the different chemistries slow down differently as the temp drops, not why.

There are some curves of performance of lithium cells vs temp in http://data.energizer.com/PDFs/lithiuml91l92_appman.pdf

Doug

That linked pdf is full of really useful information on how Li primary cells are designed. Good stuff. I also noticed in a couple of places, verbiage like:
"The non-aqueous electrolyte used in LiFeS2battery provides excellent low temperature performance"
...which tells me that the aqueous electrolyte in alkaline and NiMH batteries probably is part of the problem with low temperature performance. Very interesting.

And hey, the importance of batteries in all of our lives (and our grandkids' lives) is only going to increase over time, so I don't see any harm in diving deep for those who are curious (like me!!). I think this topic is super-interesting, even if it is a slight tangent on the topic of GPS's.

 

[DougPaul]

That linked pdf is full of really useful information on how Li primary cells are designed. Good stuff. I also noticed in a couple of places, verbiage like:
"The non-aqueous electrolyte used in LiFeS2battery provides excellent low temperature performance"
...which tells me that the aqueous electrolyte in alkaline and NiMH batteries probably is part of the problem with low temperature performance. Very interesting.

Sorry--that statement says nothing about other electrolytes. I still don't know why the other technologies degrade faster at low temps. Perhaps the anode, cathode, and/or the construction are factors.

In general, chemical reactions slow down as the temp goes down. This explains the general reduction in performance at low temps, but also says nothing about the differences in the technologies.

And hey, the importance of batteries in all of our lives (and our grandkids' lives) is only going to increase over time, so I don't see any harm in diving deep for those who are curious (like me!!). I think this topic is super-interesting, even if it is a slight tangent on the topic of GPS's.

If you liked that ref, you are likely to enjoy http://batteryuniversity.com/...

Individual datasheets for AA and AAA lithiums:
http://data.energizer.com/PDFs/l91.pdf
http://data.energizer.com/PDFs/l92.pdf

Doug

 

[hikerbrian]

Sorry--that statement says nothing about other electrolytes. I still don't know why the other technologies degrade faster at low temps. Perhaps the anode, cathode, and/or the construction are factors.

In general, chemical reactions slow down as the temp goes down. This explains the general reduction in performance at low temps, but also says nothing about the differences in the technologies.

Yes, the oxidation and reduction reactions in all batteries (and everywhere else in the universe) slow down when it's cold. But the reaction rates for all three battery types should be decreased by roughly the same factor per unit temperature. [And no, I'm not going to dig through annals of physical chemistry text to find the experimental and theoretical proof for that statement!]

Which is why I'm suggesting the issue is actually not the redox processes at the electrodes, it's the conductivity of the electrolyte - the ions can't effectively migrate through the poorly conductive electrolyte to complete the circuit. The article suggests, in a couple of different spots, that because the electrolyte solution is not aqueous in Li batteries, it maintains its conductivity even at low temperatures. Here's a bit more, from that pdf:

"When comparing cold temperature performance of the LiFeS2 battery versus an
alkaline based aqueous system, the LiFeS2 system is affected much less across a
range of drain rates (Fig. 4) and operates at temperatures where alkaline batteries do
not run at all. This is due to the use of a non-aqueous electrolyte and the high surface
area jellyroll construction. In particular, Energizer® patented electrolyte has the unique
property of actually increasing in conductivity as the temperature drops, in contrast to
electrolytes used in other lithium batteries."

Warm salt water is a better conductor than cold salt water. I believe that's a big part of the problem with alkaline and NiMH batteries at cold temp.

As for your batteryuniversity link... Well, I got through the first 731 screens/lessons, but then, I confess, my eyes glazed over...

 

[CaptCaper]

This explains why alk's fade faster and are good in the beginning. I'm still talking about the above posters issue with the Oregon with camera and flash. Not older gps's or other uses.. Again is better to use Eveeloops for his use as posted... for these various reasons. Note below each situation is different. Talking batteries is good for GPS School but we must keep the topic to what the posters are asking.

See from REI's site
" Alkaline batteries, meanwhile, are tried-and-true workhorses suitable for any device. In a GPS unit, for instance, they typically deliver about 2 days' worth of continual service. Their chief downsides: 1) rapid depletion when used in a digital camera and 2) their unending cycle of use-discard-replace."



"Apparently, the issue at work isn't how much power each of these battery holds, but how much you can get out of the battery, before it refuses to yield any more of it's energy. Traditional alkaline batteries generate power from a reaction between a zinc electrode that is stuck into a canister containing a paste of manganese oxide. This works well if the power is drawn slowly from the battery, since the reaction can spread throughout the entire volume of manganese oxide in the battery cylinder. Unfortunately this doesn't hold true when power is extracted quickly (as in the case of a digital camera, or other high power devices). When power is drawn out quickly from one of these batteries, the reaction doesn't reach the entire volume of the battery, and the paste that surrounds the zinc electrode ends up coating it with depleted reactants, which cuts the zinc electrode off from the remainder of the manganese oxide it could react with. So while you could get the full 3000mAh out with a low draw device, you may only be able to get 700 or 1000mAh when you're drawing high current with your camera.

Single use lithium batteries are constructed differently. The reactants are placed on a flat sheet, and then rolled up to fit inside the canister of a AA battery. This means that there's a LOT more reaction area, and hence more opportunity to draw as much power as possible out of the battery before a coating can build up on the electrodes. Energizer says that their 4x and 8x claims are based upon this. They also explained that the difference between their 4x and 8x products is the internal surface area. The battery layers are thinner in the 8x device, so have significantly more surface area rolled up into the canister. The Advanced Lithium devices cost less to manufacture than the Ultimate Lithium ones, so there's a nice correlation between performance and price. At least from the perspective of a manufacturer.

So 4x and 8x are actually marketing breakthroughs and not technical ones. And while it's possible to believe that the claims are true and that you can get 8 times the power out of an Ultimate Lithium battery than a normal battery, you really have to turn your thinking upside down to do so. There isn't any way to measure consistently how much you'll be getting out of a traditional battery without testing it in a particular device, and without doing so, any specific claims of better performance lie somewhere between wishful thinking and unconfirmable conjecture.

It's not that these premium lithium batteries aren't better, it's just that there isn't a way to tell if they're 4 or 8 times better, or if they're worth the price premium that they demand. "

 

[DougPaul]

Here's a bit more, from that pdf:

Don't forget that that pdf has some degree of advertising.

I'm not a chemist or chemical engineer so I'm not in position to discuss such details. (FWIW, I'm an electrical engineer and am more interested in the external characteristics of batteries than their internal details.)

As for your batteryuniversity link... Well, I got through the first 731 screens/lessons, but then, I confess, my eyes glazed over...

I may have read through most of it a number of years ago (when it was smaller), but now I just read read sections relevant to my interest of the moment. In any case it is a very comprehensive source with professional-quality info.

Doug

 

[wardsgirl]

I took my GPS out into the woods for the first time yesterday! I can totally understand the need for the battery discussion above because I have discovered that this is a battery-eating machine! I think I may have turned some bits on that were unnecessary, and I will rely on this group's wisdom to help me out. All in all, I got the GPS to do everything I wanted it to do, which, as you may recall, was to give me the white arrow that I could manipulate to a spot on the map, then get the distance to said spot to appear in a numerical readout at the top of the screen. I did it and it was absolutely wonderful! How far to that stream? Why, it's .53! How far to that intersection? It's 384 feet! How far up this blasted gulley to the top of Mt. Paugus? A grueling .68! What a joy to hike with this magical device!

And now for my n00b questions about my Garmin 64s:

1. Can the GPS operate with dead batteries if it is attached by the USB cord to my laptop? I'm guessing no, but I want to make sure.

2. When the GPS is on, and I click the power button once, I get a screen with the time, date, backlight, battery, and GPS indicators. I think I have figured out how to make the backlight set to 0, but is there a way to disable this screen so it doesn't show up and instead when I click the power button I am taken directly to the map?

3. Is there a way to make it so that North (or magnetic north) always appears at the top of the display screen? (other than just orienting myself to facing north like I would do when navigating with a map and a compass?)

4. It seems that I must have something turned on unintentionally, because my map on the screen has a blue line that denotes the trails I traveled yesterday. What have I done? How do I turn that bit off?

Thanks so much for everyone's help in this thread!

 

[CaptCaper]

I just bought a Monterra which could be the biggest battery eating beast of gps's out there ...but it isn't..neither was my Montana's.you have to set it up not to be.. Every gps menu seems to be different..similar but still different.. But there isn't any reason you can't get yours to run all day and then some.

I enjoyed a quiet hike into the Dry River wilderness running it on glonass/gps/ waas and full track recording.. never shut it off. Took some video,pictures and plenty of playing with screen on. Got back and the meter didn't budge.. used so little it wasn't noticeable..same last night leaving it on over night to test it was the same again it didn't drain...
I learned how to use it by brightness control and sleep modes.. lock screens,etc. And still be able to navigate all day. Also make sure you fully charge the battery in the wall socket they give you.

You'll get it worked out with some practice and understanding.. your gps should not be a battery beast at all..you are doing something wrong.

Yes you can operate it with dead battery but the battery has to be in it.

The blue line are the tracks.. you can configure them save them or delete them in track manager.

Never owned a 64 series so I can't help with the power button.. wiki spaces must have a good manual for yours as they do for mine.

I always use mine in Track Up.mode so the arrow does show all the time..some like North Up for map preference.. all in the setup for maps..