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dfx

Garmin Oregon 450 power consumption tests

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In an attempt to further(?) dispel the myth that having WAAS enabled or having the magnetic compass enabled has any significant impact on battery life, I decided to repeat the excellent tests that tomc61 has performed on his Vista HCx and has posted here.

 

However, I'm not as professionally equipped as he is and only have a cheapo digital multimeter, which has a few limitations. Most importantly, it isn't able to give proper min/max/average readings, and since naturally there's some constant fluctuations in the readings, all numbers given below are averages simply estimated by me.

 

Furthermore, it only has options of measuring currents up to either 200 mA or up to 10 A. The problem with the 200 mA setting is that the Oregon occasionally draws more current than that. I tried replacing the 200-mA fuse with a piece of tinfoil, and while that worked for a while, eventually the multimeter got confused by high currents and started to give nonsense readings. So i had to use the 10 A setting, which unfortunately only gives me two digits after the comma, in other words is accurate to +-10 mA only. I think it's still meaningful enough to get the big picture though.

 

Test setup

I was using a stable 3 V power source (AC adapter) instead of batteries. Tests were performed on our balcony, where I had the Oregon sit for a while so it gets a somewhat decent signal. Test subject was my Oregon 450 with the latest firmware. Pictures of the highly professional setup are here and here (yeah, I only had two croc cables available, so I had to improvise).

 

Booting

During booting, the unit pretty much constantly draws 200-210 mA until it's done booting. For a second or two it drops to about 100 mA, but then goes right back up.

 

WAAS enabled, compass enabled

This is how I usually use the Oregon, so after I got a decent signal I started looking at various screens to see how much power it consumes. Backlight was turned off completely. Note that the unit was never able to get a WAAS lock throughout the whole test (it was, after all, our balcony), but the satellite status page showed that it was trying. Again, all numbers are rough estimates made by me due to the limitations of my multimeter.

 

Main menu: 90 mA

Satellite status screen: 100 mA

Compass screen: 180 mA (which came as a surprise)

Map screen: idle (not redrawing): 90 mA, redrawing: 200 mA until it's done. In other words, it was drawing 90 mA until i turned the unit slightly (compass was enabled) which caused it to redraw the map. Current went up to 200 mA for a few seconds until the redrawn map appeared on the screen. I have Birdseye loaded, so that makes the map redraws a bit slower.

Menu movement, i.e. any kind of scrolling around or opening/closing screens: estimated 150-180 mA but only momentarily (for less than a second or so).

Blanked map screen (blanked by the "power save" option): 90 mA, even when the unit is being turned. The map redraw is delayed until the screen comes back on.

Backlight: Turning it up to 50% adds an estimated 10-20 mA to the power usage, 75% backlight about +30 mA and 100% backlight about 70-80 mA additional current.

 

WAAS disabled

I disabled WAAS (with compass still on) and looked at all the same screens as above again. All the numbers came out the same, there was no noticable difference at all. This means that WAAS additionally consumes less than 10 mA of power, and likely much less than that.

 

WAAS enabled, compass disabled

Again I looked at all the same screens as before and again the numbers came out the same. Even the compass screen still drew a constant 180 mA, even though it now had no reason at all to refresh or redraw anything, as I wasn't moving. I got curious to see if screen blanking ("power save") made any difference while on the compass screen, and even after several minutes of the screen being blank, power consumption was still 180 mA.

 

My conclusion is the same as tomc61's, that neither WAAS nor compass has a significant impact on battery life. From my limited accuracy multimeter, I would estimate that the difference is less than 5% and probably much less than that. Additionally, the "power save" option only seems to make sense when you're sitting on the map screen, and the backlight seems to be less power hungry than I thought, at least when set below 50%.

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Map screen: idle (not redrawing): 90 mA, redrawing: 200 mA until it's done. In other words, it was drawing 90 mA until i turned the unit slightly (compass was enabled) which caused it to redraw the map. Current went up to 200 mA for a few seconds until the redrawn map appeared on the screen. I have Birdseye loaded, so that makes the map redraws a bit slower.
This is insightful. Since the power save mode forgoes map redraws and when you're moving redraws are a constant, then having power save on will have the most possible battery savings.

 

I'll now enable Power Save, on longer trips and put up with the inconvenience of having to touch the screen to see a map. For shorter trips, under 10-hours, I'll disable Power Save.

 

Helpful data, thanks for the tests. ;)

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My take home message is that aside from booting, screen updating consumes more power than any other function. Hence battery save option (disabling the sceen) is the most effective way to conserve power. One perplexing result was the compass screen drawing 180mA even after batt save mode blanks the screen. I just can't figure out why that would be. Any speculation?

 

PS: thanks for the testing.

Edited by yogazoo

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One perplexing result was the compass screen drawing 180mA even after batt save mode blanks the screen. I just can't figure out why that would be. Any speculation?

the only explanation that i can come up with is that the "power save" function is implemented in a very specific manner and doesn't actually disable screen updates per se, but that it's rather the individual "applications" (the different screens) which have to check whether the screen is blanked or not and then simply stop redrawing. the map screen seems to do that while the compass screen doesn't.

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as a side note, after having run those tests, i now had to recalibrate my compass for the first time ever. either the increased voltage during the tests has thrown it off, or it somehow lost the calibration while i had it turned off.

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Care to see if there is a difference with chirp on /off, and if you actually have a chirp to see the power useage when gathering chirp data? I suspect its minimal, but .....

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Care to see if there is a difference with chirp on /off, and if you actually have a chirp to see the power useage when gathering chirp data? I suspect its minimal, but .....

i can try enabling chirp searching, but i don't have a chirp to test. i'll do that after the weekend.

 

Do you suppose Garmin’s 16 hour battery life rating is a calculated? 2300 mAh batteries/145mA average=16 hours.

most likely yes, as obviously battery life heavily depends on how you use it. if you leave the map screen open all the time and don't blank the screen, you'll get much shorter battery life. who knows what kinda usage pattern they used to calculate their ratings...

 

also note that those tests were on a 3V power source (or more like 3.3V according to the multimeter) and not on 2.4V as you'd have with NiMH batteries. to be honest, i have no idea how electronics behave in this case, but i'd assume that the current goes up as the voltage goes down. but i don't really know. something else to try next week when i get bored, if i can figure out how to hold the batteries in place...

Edited by dfx

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Great tests and interesting results. Sounds like redrawing the screen, whether on the compass or map page, is the biggest source of battery drain.

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Ok, so I repeated the tests with a set of (almost) freshly charged Eneloop NiMH batteries. Again the setup was highly professional, using a magnet to keep the battery in place (heh). For pictures see below.

 

I forgot to check the voltage of the batteries before I started with the tests, but after the tests they both came out at about 1.26 V and the Oregon was somewhat undecided between giving them 3 and 4 green bars. The funny thing is that during the tests, while the current was going through the multimeter, the Oregon detected the batteries as being almost empty (only a red line left). Everything still worked as expected though.

 

Tests were again made with backlight turned off and initially WAAS and magnetic compass enabled. And again, all numbers are averages estimated by me.

 

Main screen: 110-120 mA

Sat status screen: 130-140 mA

Compass screen: 230-250 mA

Compass screen blanked by "power save" option: 230-250 mA

Map screen when idle: 110-120 mA

Map redraws (either caused by movement or panning the map): momentarily 280 mA until done

Map screen blanked: 100-120 mA

 

Then I both disabled WAAS and the magnetic compass.

 

Main menu: 110-120 mA

Sat status screen: 130-140 mA

Compass screen: 230-250 mA

 

In other words, absolutely no change in the numbers. I repeated the enabling and disabling of both compass and WAAS a few times to see if I could spot at least a small difference in the current it pulls, but the numbers remained absolutely unchanged.

 

With WAAS and compass enabled again, I also enabled Chirp searching and returned to the main menu. Now I could see an increase in the current. Again I repeated enabling and disabling of Chirp searching and kept returning to the main menu. With Chirp disabled, the numbers would mostly hover around 100 and 110 mA and sometimes go up to 120 mA, while with Chirp searching enabled they would more hover around 110-120 mA and more frequently jump to 130 mA. I would estimate that having Chirp searching enabled draws an additional 10-15 mA on NiMH batteries.

 

Unfortunately this is about as precise as I can be with my limited equipment B)

 

Here's a few shots I took: The complete setup, compass screen peaking to 250, main screen showing an infrequent peak to 140, idle map screen showing a low of 100, and compass screen with a low peak of 230.

img3237m.th.jpg img3238a.th.jpg img3239c.th.jpg img3240q.th.jpg img3242nm.th.jpg

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I forgot to check the voltage of the batteries before I started with the tests, but after the tests they both came out at about 1.26 V and the Oregon was somewhat undecided between giving them 3 and 4 green bars. The funny thing is that during the tests, while the current was going through the multimeter, the Oregon detected the batteries as being almost empty (only a red line left).

No photos of your battery lash-up, so it's hard to say what happened. Whatever it was, it was clearly adding 0.4V or more of a voltage drop between the cells and the Oregon. Really shouldn't be your meter -- might have been the quality of the connection to the cells -- not easy to get a good connection without either an external holder or some soldering to the cells.

 

So (gasp) you mean those microamps of current being used by the compass chip don't hurt after all? B)

 

TFTT (thanks for the test)

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No photos of your battery lash-up, so it's hard to say what happened. Whatever it was, it was clearly adding 0.4V or more of a voltage drop between the cells and the Oregon. Really shouldn't be your meter -- might have been the quality of the connection to the cells -- not easy to get a good connection without either an external holder or some soldering to the cells.

actually the first photo shows the contraption, just need to look closely B)

the second battery was in the regular battery compartment of the oregon.

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No photos of your battery lash-up, so it's hard to say what happened. Whatever it was, it was clearly adding 0.4V or more of a voltage drop between the cells and the Oregon. Really shouldn't be your meter -- might have been the quality of the connection to the cells -- not easy to get a good connection without either an external holder or some soldering to the cells.

actually the first photo shows the contraption, just need to look closely B)

the second battery was in the regular battery compartment of the oregon.

OK - I'm guessing you've got another alligator in there. The ball pivots on the "stereo roach clip" (a long story comes with that name), even when tightened, may not be as conductive as you'd hoped. What's connecting the bottom of the Eneloop that is external? I see something there that says "Hands Free" "Super Cellular" somethingorother with what looks like some foil, but I don't see what's keeping tension on the foil/cell junction. Using NiMH, it's understandable that even a little voltage drop in the setup would put you in the "red".

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What's connecting the bottom of the Eneloop that is external? I see something there that says "Hands Free" "Super Cellular" somethingorother with what looks like some foil, but I don't see what's keeping tension on the foil/cell junction.

it's a magnet :anibad: told you, it's a super high professional setup B)

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as i now have a chirp available, i decided to do some more testing with it and see how it behaves. this time, instead of trying to come to conclusions myself, i recorded a video of the whole process. see for yourself! ;)

 

the first part of the video shows the setup, the boot sequence and a repeat of all the previous tests. the second part of the video emphasizes on the chirp. there's no audio as all you'd have heard is the jackhammer from across the street. :unsure:

 

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This is not scientific at all, but I just know I am very disappointed with the NiMh battery life in the Oregon 450T that I have. I am used to the 76Cx and it seemed to last for weeks. The 450T seems to only last a couple of hours. I am now back to alkaline and I'm going to try NiZn next.

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as i now have a chirp available, i decided to do some more testing with it and see how it behaves. :unsure:
So what is the executive summary in text form?

 

As always, thanks for your tests.

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So what is the executive summary in text form?

as already mentioned before, i'd estimate that having chirp searching enabled consumes around 10-15 mA. it's not a constant power draw, but rather seems to cause increased fluctuations in power draw upwards, which makes it really hard to estimate for me.

 

talking to the chirp also consumes very little power, i guess most of the power draw actually comes from showing the information on the screen with all those screen animations going on.

 

once it's connected to a chirp, power draw seems to go down slightly. it seems that once it has downloaded the info from the chirp, it stops talking to it, which can also be seen in the fact that the oregon doesn't detect the chirp going out of range (by taking the battery out of the chirp). i don't know if it's able to detect a second chirp while in that "connected" mode, or if it requires a manual disable/enable of chirp searching to do that. if it in fact stops talking to the chirp completely and also doesn't search for one, then i assume the latter is the case.

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one problem I saw in the vid

your batty indicator was showing only 1/2 full when you started the test/video

why not use a fresh charged cell?

it may make a difference

 

as i now have a chirp available, i decided to do some more testing with it and see how it behaves. this time, instead of trying to come to conclusions myself, i recorded a video of the whole process. see for yourself! :sad:

 

the first part of the video shows the setup, the boot sequence and a repeat of all the previous tests. the second part of the video emphasizes on the chirp. there's no audio as all you'd have heard is the jackhammer from across the street. :laughing:

 

Edited by salsaguy

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one problem I saw in the vid

your batty indicator was showing only 1/2 full when you started the test/video

why not use a fresh charged cell?

it may make a difference

actually they were freshly charged, i already mentioned this in my post #12 above. i assume that running the current through the multimeter causes a slight drop in voltage, but i can't say for sure.

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