Lowest possible battery consumption while cycle touring.

Knut Schleisiek shared this question 7 years ago
Answered

hi,


I would like to setup my phone (rooted Defy+ cm10) for a really low Battery consumption, while having display/GPS and Locus always on.


Maybe something with a Tasker APP switching the phone in a "touring state"?


Any Tips welcome

Comments (17)

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To my knowledge exactly display and GPS are the parts of a smartphone with the highest battery consumption. So what would it help to reduce battery consumption by few %?

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well a few % here and there add up, not on a weekend, but on a longer trip, sure.


getting rid of unneeded system apps, max cpu to the lowest possible setting for locus, brightness tinkering...or maybe there is a golden GPS hack that reduces Energy consumption...or or or


the main reason of course, I love fooling around with my 2 favorite toys, android and Locus.

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Hi Knut,


If it can help. I use a rooted Defy+ CM 9. Personally, i use also Android Assistant to optimize the memory (with an autoboost set to 10 mns) and so the battery consumption. I also take care to have 2G only (i doesn`t need the 3G with the offline maps) , bluetooth off and all the apps on SD with app2sd. I`ve got good results with that.


Do you use the same parameters ?

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ah I forgot, my phone is already connected to the generator hub of my bike, so in flat terrain I am self sustainable, but in hilly terrain my weak legs just aren`t able to charge the phone

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hey Fifi,


I have pretty much the same setup, but i go one step further. I don`t install apps, my system is nearly bare minimum, all the other, non crucial APPs are Titanium Backups on my SD, so when I need the "facebook app" I restore it, post something stupid and deinstall again.


I have to check about this Android Assistant though


thanks all

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seems you`re really taking is seriously "so when I need the "facebook app" I restore it, post something stupid and deinstall again" :)


from my experience, expect that half of energy take screen, around next 40% GPS and rest is by CPU used by Locus and the system itself.


So in first place, I suggest to start with screen and reduce usage as much as possible


In second place, suggest to check "GPS auto-off" feature in Locus (settings / gps). This allow to reduce GPS usage in the cost of reduced number of recorded points


And finally, I may only suggest reduce usage of CPU in locus itself. So usa offline maps rather then vector, display only minimum points and tracks on map and do not use rotation. That`s all what I have on mind now ... just an suggestions

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thx menion, I will test this GPS auto off feature.


I will also try to find the lowest possible CPU speed for Locus, or maybe Locus/Andoid does that by design?

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Hi Knut,


in case you need the display on mainly for guiding resp. navigation, I have one more idea which really saves a lot of battery:


Use https://getsatisfaction.com/locus/top... with display off!


Btw. I don`t think the Facebook (I personally don`t use it) app drains the battery much if you`re not


logged in whereas install/uninstall of apps consumes quite a lot battery.

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Ahm, in the case of guiding with your ears you should not use GPS auto off.

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CPU speed : hmm if i`m not mistaken, CM already does the job

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Ok, thx, that makes sense, will have to dig into guiding then.


Facebook was just an example for a big Syncher, I don`t constantly install /deinstall apps when away from a wall charger.


Keeping the bare minimum but having everything offline, like that knot manual.

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If its mainly about track recording and not guiding, the "GPS auto off" feature really does *wonders* to your battery life. If you`re happy with a recorded point every two minutes, your phones cpu will be in deep sleep mode for about 110 seconds and only awake for as long as it takes to get the next gps fix. Using this technique, I was able to record three full hiking days in the scottish highlands on one battery charge (samsung galaxy note, 2500mAh battery). Some display looking and some music listening was also involved.


The key idea here is to get your CPU into deep sleep state. There are many things that can prevent this on Android, like a constantly enabled GPS, a few thousand misbehaving apps, email syncs, the moon phase, or whatever. I found that enabling "airplane mode" is usually enough to shut down all that crap and keep it quiet. Uninstalling seems a bit of an overkill.


The amount of energy you can save with "GPS auto off" also depends greatly on the quality of your phones GPS hardware. If it takes too long to acquire a position when turned on, you lose most of the benefits.


You can check how much time your phone spends sleeping with the tiny free app "CPU Spy" in play store.

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1. In 2 minutes I walk about 150 meters. For some situations that recorded track would be rather in-accurate.


2. I will check again with airplane mode, but last night I had Locus on with GPS disabled but synching of email, twitter and news on and I used 20% of my battery. Locus did not even show up in the batt stats. Cpuspy tells me 15% deep sleep and 77% on lowest is 300 mHz.

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Only 15% deep sleep over night with nothing really happening is quite bad. It should be closer to 90%. Deep sleep vs Lowest CPU does make a huge difference in energy consumption. Good luck in figuring out the offending app. "Better Battery Stats" or "GSAM Battery Monitor" can be used for this. They can both count the number of times that apps wake up the phone.


And obviously a two-minute-track is inaccurate. I prefer ten seconds myself when I know I have enough energy. But it is good to know that Locus can last longer if neccessary.

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Sure thanks and as I said, wifi and synching was on. No need for that in a mountain hut; I will remember that one.

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One more question.


Is it possible to black out the screen on a straight stretch of a route? This could work a bit like the guiding feature.


For example:


I ride happily along my track but for the next 5 Kms the track is just a straight line/ street. At this point the app could easily turn off the screen and turn it back on again 100m before the next junction to save some power.


Is that possible? or will the Systems built in screen saving measures screw that up?

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unfortunately this is not possible. I was trying to find working way to handle on/off state of screen (it was in topic with proximity sensor) and discovered that for this exists only some unsupported methods that do not works correctly on all phones