GPS Power Consumption

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ConRAD
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GPS Power Consumption

Post by ConRAD »

Using gps at 0% backlight during daytime normally proved to be more than acceptable.
However since gps is by far the more demanding gadget from the energy point of view the question is: do exist gps devices requiring less power than the values reported here below ??

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Bicycler
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Re: GPS Power Consumption

Post by Bicycler »

Anecdotally, I estimate I get 2 or 3 hours more life out of a pair of AA cells in my Etrex 30 than I did with my old 60series in normal use and this seems to apply when using the backlight (50%) as much as when I am not using the backlight. With both units I usually use the settings which maximise battery life.
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CJ
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Re: GPS Power Consumption

Post by CJ »

I was going to ask why power consumption was so important, when any hub dynamo should produce enough power to run even the Montana - provided you didn't need to run lights at the same time. Then I remembered where I'd seen 'Bikeinthenight' before!
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willem jongman
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Re: GPS Power Consumption

Post by willem jongman »

I recently bought my first GPS, an Etrex 30. I chose that model because it was one of the cheapest, lightest models with just about the lowest power consumption (on the other hand big touchscreens are power hungry). Riding from Italy back to Holland along tracks that I had downloaded in advance I discovered that my battery lasted much longer than expected. I had been told to expect about two days of riding, but a set if two batteries lasted a full five days of about 7 hours riding a day. This was with Ansmann 2500 Eneloop type batteries. I also tried a set of older GP batteries, but these lasted only two days. My conclusion is that battery technology has improved a lot in recent years (and is likely to improve even further), and that with frugal settings on a frugal gps one needs neither a hub dynamo (although I have one) and something like an EWerk, nor even a regular mains charger. Six or eight high end rechargable batteries should be enough to see you through most holidays, long and expedition type rides excepted of course. It keeps it so much simpler. As for the telephone, I just switch it off most of the time.
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bikes4two
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Re: GPS Power Consumption

Post by bikes4two »

> Might power consumption be influenced by the amount of detail being displayed on the screen and the refresh rate (I'm thinking processor power here)?
> For instance, compare say the 'screen refreshes' need when travelling through a built-up area (lots of side turnings and other detail) vs a rural setting with much fewer roads/lanes.
> How much you are zoomed in or out will also influence the screen refresh task too
> And how detailed your mapping info is (Garmin Metro 'roads only' line type info vs say OSM or OS mapping detail)
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willem jongman
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Re: GPS Power Consumption

Post by willem jongman »

I try to make life easy for the gps (and myself). I follow a downloaded track, so the gps itself does not have to calculate my route on the go (that would consume rather more). The map I use is an Openstreet map, and it is usually zoomed in to the 80m level. And I do not normally need screen backlighting.
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Mick F
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Re: GPS Power Consumption

Post by Mick F »

I have a Garmin Montana and the Li battery will go for 15hrs easily with the backlight off.
Fit Duracell AAs and it could go maybe for 24hrs with the backlight off. Never tried it.

I've never bothered using it with the backlight off as it goes for long enough even with the backlight at 60%.

If I'm on a long ride, I'll fit my Eneloop AAs and take the Li battery fully charged with me. That way, I couldn't give a toss how much power it consumes. It's a pointless question really.
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beardy
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Re: GPS Power Consumption

Post by beardy »

If I'm on a long ride, I'll fit my Eneloop AAs and take the Li battery fully charged with me. That way, I couldn't give a toss how much power it consumes. It's a pointless question really.


Only pointless if you dont mind running out of GPS when you are out on the ride. If on the other hand you wish to know whether to, or how many, batteries to take then it has a point.

You obviously did give a toss how much power it consumes as you took spare batteries for the long ride.
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Mick F
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Re: GPS Power Consumption

Post by Mick F »

Nope.
You're wrong.

I took Eneloops on my ride Up North in May, plus a fully charged Li battery, as well as the Garmin charger and an AA battery charger. It was belt and braces, as I wasn't sure if I could recharge easily on my overnight stays.

The Montana has a battery level indicator and warning - most/all other devices do too. All I needed to do - if required - was to switch off, replace the battery and switch back on again. Two minute job and carry on riding. The fact that I wasn't riding for 20hrs+ in any one day was ok by me!

If I went onto the third day of riding without a recharge, I'd have bought some disposable AAs.

As I said, I reckon its a pointless question regarding the power consumption. They go all day ....... easily, and recharge over night.
Mick F. Cornwall
beardy
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Re: GPS Power Consumption

Post by beardy »

So as long as you ride restricted days, carry spare batteries and two chargers and have overnight access to mains electricity and are cycling past shops that are open and selling AA batteries it is not worth thinking about.

On the other hand you could think about the device's power consumption and know what you need to carry for the journey. I have to admit that I cheat in this respect, most of my riding is pretty repetitive so I just know how many batteries I need from previous rides.
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Mick F
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Re: GPS Power Consumption

Post by Mick F »

Yes.
Experience will tell you, but so does the spec. The spec tells you how long batteries last. The power consumption is besides the point.
Screen shot 2014-11-01 at 10.36.20.png


If you want to go off and away from local facilities, you have two options.
Use a dynamo with a USB output.
Buy a device that will take AA batteries ...... many of them don't ..... and take one set per day.

If you can guarantee access to a 3pin socket overnight, you have no worries whatsoever.
Mick F. Cornwall
beardy
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Re: GPS Power Consumption

Post by beardy »

The question was however about how much effect using the backlight has.

In his case to see if the dynamo was up to the job for running all GPS's with the backlight on.

For the rest of us it can bring down that book figure of 17 hours and it is of interest (to others) by how much it comes down with the different GPS's and different backlight settings. My natural frugality means that I only use the backlight on the minimum setting and even then only at night.

Like most people, I only do the really long rides outside of the winter months, so I dont test the batteries' capacity with long rides which have a majority of backlight on. Like the OP I was quite surprised at how different the effect of increasing the backlight was on the two GPS's that he tabled.
willem jongman
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Re: GPS Power Consumption

Post by willem jongman »

I at least am interested in such information because for me battery life is important. If I don't have to take a charger on most trips that is one thing less to carry, and one chore less to attend to in the evening. I do not normally use the backlight.
Brucey
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Re: GPS Power Consumption

Post by Brucey »

Mick F wrote: ....The spec tells you how long batteries last. The power consumption is besides the point....


well not really... it says 'up to 17 hours' which you can obviously reduce by using the backlight, or by having slightly old batteries or whatever.

BTW if the backlight is regularly a make-or-break feature, might it be worth fitting an external LED lamp? Would this illuminate the screen well enough? I daresay that 10mA @ 6V might be enough power to enable you to see if it is used in the right way at night. This would be barely noticeable as additional load on a hub generator, for example.

cheers
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ConRAD
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Re: GPS Power Consumption

Post by ConRAD »

As far as I'm concerned even in the darkness of the night 0% backlight is ok ... in this case I just need to toggle light on-off for a short while to understand what's going on ... that's it !!
BTW … do you know that some gps devices, when powered via usb port, still consume some power even if they are simply switched-off! ??
Montana 600, just to make an example, under switched-off conditions, takes approx 30mA quite likely to maintain satellite receiver active and a few basic functions such as mileage totalizer etc.
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