yashsingh1/xdaforums huggingface dataset:
[Desire General] FlatEric83:
Very good post guys, and indeed I like the tech insights of th3 and bemymonkey, plus all the others putting effort in the thread, I used to work with batteries a little bit (for HEV, no phones :p) and the power management of our Desire intrigues me a lot.

As it turnes out, the main plague for our batteries is the screen when not using some CPU intensive tasks like games, and dimming brightness helps a bit.

I was actually looking for auto-brightness tweaking on non-AOSP ROMs (cannot get away from Sense ROMs :)) but seems that this is not yet available...does anybody know if this is related to kernel differences or just there is no porting to Sense ROMs?

@ andycted: I imagine you, as me, are locked on 3 Italia 3G network. As far as I read from older posts, this is a juice bogus...I'm gonna try this night to force to roam the phone to 2G and see if I get lesser percentage drop overnight (usually 3-5%).

It would be even nicer to see if, in presence of costant Wi-Fi coverage, switching to roaming may affect positively battery duration by more than a quid. Alas, 3 Italia requires to be under his coverage to use some optional services, as "Insieme" or other...but if the effects are noticeably better, it could be a last stand for emergency situations where we, arm 3 Italia users, have to be away from power outlet for much time :)

Last, I was wondering about a sentence I read before in this post (probably by th3, but not sure), about difference of having Mobile Data turned off (via Power Button held down options) or just dis-engaging APNs (like JuiceDefender, which I use, usually do): is there a significant difference?
[Desire General] andycted:
Indeed I am ! But I really think about it as plus, since when I compare signal strength to other networks (in my town), there isn't much difference and comparing data speed to more expensive ones, it's way faster. Of course you are right that 3G mobile drains more, but for what we tested, it seems it is only the case when having voice calls and data transfer, but for idle it could even be a tad better or more probably the same/negligible difference.

I'm quite interested in what you will find, but battery % isn't always reliable and, I might bee wrong, but years ago you were advised that roaming was draining more battery.

Regarding aosp builds and automatic brightness: I believe it's a kernel related function and we won't be able to see it in htc based roms. Unfortunately.

It's not extremely practical carrying an extra battery sometimes but they are at least cheap.
[Desire General] th3:
Their research group would like to get hold of a Desire to model its power characteristics before saying it works on the Desire. Hence why currently only the N1 and some others are officially supported. But I'm already asking and giving feedback on all you've mentioned even though I haven't replied on those points here. They strictly want to avoid 'feature bloat'.

I don't think I'm currently in a position to say, sorry. Does it stop the CPU (and SoC) from entering into the normal sleep mode?

Snapdragon as a whole is very low power in sleep mode, let alone the CPU portion alone.

-----------------------------------

- Sent via my HTC Desire -
[Desire General] FlatEric83:
As you presumed correctly, the difference was negligible, still 5-6 % overnight (maybe just 1% less than usual..

Yes, 3 Italia offers quite good offers, so I'm happy to stick with it.. unfortunately at my place signal strength isn't top notch (-90 dbm usually)

That's a shame, I'll have to tweak brightness by myself :-P

Sent from my HTC Desire
[Desire General] bemymonkey:
Screw extra batteries, just get a Gum Pro or some other USB power pack. If you plug in at 20%, half an hour later you're at 70%... :)

@th3 thanks for the source link!
[Desire General] andycted:
But if I'm at 20% and replace my battery, one minute later I'm at 100% ! Plus, it's smaller and cheaper. I bought a dock charger with space for an extra battery and quite happy with that.

Anyway, setcpu supposedly can lick the frequency to a value, say 245 Mhz, while screen off. It would be curious if this wasn't already implemented in the phone itself in some way.

Regarding 3 italia, at home I get around -75 dBm and I suspect sometimes that 3g data burns less than my spotty wifi...
[Desire General] bemymonkey:
But a spare battery requires you to reboot ;)... Not to mention not being able to charge your other gadgets :p

Do you have a separate charger for the spare battery? Or do you swap them around to charge?
[Desire General] andycted:
Table Dock charger, with an extra space for spare. Don't have other gadgets !!!
[Desire General] FlatEric83:
All my other gadgets became drawer ornaments since Desire. No more MP3 player, no more GPS, I use a reflex so Desire is just OK as P&S camera :) Even notebook is no more a necessity for some mobility tasks.

The dock+spare battery seems to me a good idea if you work alot in office/home, since you can have your phone sitting on the desk comfortably, and use it through the day (e.g. having IM or FB running on phone since maybe your office internet policy doesn't allow you to connect to such services).

Just a doubt keeps me refraining a bit over this solution (sorry if I explain this here, but seems that at least we have some pretty experienced people, and it is alway related to battery topic): if I'm gonna use a powered desk dock for 4+4 hours a day, the battery will be with a good chance always at 100%.

We know that since a couple of updates from HTC the recharge routine of the Desire tops up the battery and then, after ~1h it will halt the current flow to the battery and let it deplet till ~90%, and then restart the cycle to top-up the capacity.

This routine works greatly in avoiding overcharge, which is a known battery-killer. But indeed this, under a most-of-the-time connected scenario, will grandly increase the recharge cycles of the battery.

Alas, AFAIK from my brief experience with HEV batteries, another usual characteristic of Li-ion batteries (and generally any battery) is a limited number of recharging cycles that a battery may withstand before dropping its capacity under a reasonable amount (usually 80% of original is considered the frontier).

Anybody with better knowledge of batteries than me, and specifically mobile devices Li-ion, has a clue if this 100%-90%-100% so will indeed decrease battery lifetime?

If it is so, and I have a bad feeling about this, how it would be possible to take advantage of desk cradles without depleting battery nor overcycle it?

Best would be to have some charge-sustaining behavior, or even better could be also have the phone sitting on the cradle without battery at all, but I've tried to connect phone w/o battery to the charger and it doesn't turn on...

Very practical charge-sustaining procedure could be attaching the phone to PC via USB charging (only around 500 mA drawn) and tuning the usage on desk to have a consumption of such current :D But this is a really rough workaround at my eyes :)

Again, sorry for going a little OOT :)
[Desire General] andycted:
In my experience, the drop and recharge issue is so rare that I didn't even had it once. There are even some kernels that explicitely removed the functionality.

Instead i find that, probably because the charger is cheap, probably because it works in usb mode and probably because it's charging another battery at the same time, it takes about 8 hours to charge while the phone is on and about 3 when the phone is off. This from almost empty.
[Desire General] bemymonkey:
If you add, say, a 2A charger, you should find those charge times dropping to around 2 hours while charging both the phone (on) and the battery at the same time :)
[Desire General] andycted:
How do I add the 2A charger to the dock ?
[Desire General] bemymonkey:
Just replace the old underpowered one with a 2A charger ;)

I'm guessing you bought something like this: http://cgi.ebay.com/USB-Sync-Deskto...G7-/140441570670?pt=AU_MobilePhoneAccessories

Or did you buy something with a charger integrated right into the dock itself?
[Desire General] andycted:
I don't think it will change, I'd have to short the pins to make it believe it's a socket charger, risking to burn the plug.
[Desire General] FlatEric83:
Well, if it's like that, is even more risky to let sit on the dock the phone for many hours at full charge, since there is chance to overcharge the battery without that mechanism, which has indeed been introduced to avoid such issues.

So, with overcharge protection you get "lots" of cycles, without you risk overcharge...:(
[Desire General] bemymonkey:
Hmmm... I keep forgetting that people use docks for connecting to the PC as well as charging. Wall chargers > USB Ports ;)
[Desire General] bemymonkey:
Why overcharge? The charging electronics stop charging at 100%. It's been this way for years on pretty much all devices that use lithium ion batteries... :confused:
[Desire General] th3:
OK, then it's close to useless. Screen off by standard is when the SoC enters standby where the CPU is nearly fully off (clocks are not running, 0MHz) and there is about 2mA total phone draw with the vast majority of it not by the CPU region. The current requirement for LP chips in that state is mostly leakage current and you can't decrease that on a fabricated chip unless you tweak the standby Core voltage, PLL voltage, IO voltage and threshold voltage.

As for charging; my phone charges at 650-700mA DC until it reaches 80% ish where it drops to 250mA region. Then it drops once more to 125mA region after 90% ish. I've observed this since the beginning. It cuts off charge at 1355mAh (reported as 100%).

-----------------------------------

- Sent via my HTC Desire -
[Desire General] andycted:
Try using a different cable/charger than HTC one and it will go to 'usb' charging mode. That supplies a lot less current and I suspect my dock charger supplies even less.

Thanks for the tip on SetCPU, I suspected as much, since even the developer says you probably shouldn't touch profiles...
[Desire General] bemymonkey:
If actual "chargers", and not docks that require the data pins to enable communication with a PC connected to the dock, do this, then I'd classify them as defective. A charger with the sole purpose of charging the phone as quickly as possible should not identify as a "USB Device", causing the Desire to limit its intake of power so as not to overload the fictional USB device...
[Desire General] FlatEric83:
Regarding putting setCPU to force 250 MHz at display off, this may be useful not for reduce further what is not reducible, but to prevent some programs (i.e. scheduled tasks, or worse some cycle-sucking program that went bad, I had an issue with Setting Profiles one night - now solved with update) to drain too much power while screen is off and intended to be in sleep or at least low-power consumption.

Regarding overcharge, it may happen that a mis-calibrated battery management chip may overcharge the battery. Or at least I'm guessing why at HTC they changed the charging profile to do this 100-90-100% cycle.

It is pretty well known that letting a constantly-attached battery device to AC do shorten battery life, but usually I was thinking more about the little charging cycles that happen between charging stops and re-start after the battery get consumed by a bit.

It would be nice to know more on this topic for Li-ion...
[Desire General] andycted:
You two seem to say opposite things in two different threads, about at the same moment. http://xdaforums.com/showpost.php?p=7737001&postcount=161

What do you think ?

By the way, I had a S-LCD desire in my hands for a moment, enough to apply root for a friend of mine, but not enough to test display battery usage. the bastard snatched his phone as soon as I was done and fled. But I'll get my revenge soon enough !

Edit:

S-LCD on airplane mode:

max brightness = 250 mA

Medium-low brightness = 160 mA

Min brightness = 121mA

Overall I'd say it depends where/how you use your phone, but amoled can shave many mA with dark screens
[Desire General] FlatEric83:
Well, I've found thi site http://batteryuniversity.com and it's a pretty good source for technical informations on batteries. I've also checked around the web if it is considered trustworthy or not, and it is.

I've read here and there in that site, and I've found some useful informations.

Regarding the recharging cycle, it is possible to see how it is usually done at this page http://batteryuniversity.com/partone-12.htm :

that page also gives a good overview on charging and how should be a battery charged, indeed some tips given are the following:

Please note that 4.2 V/cell is typical for Li-ion, and Desire cell is no stranger to this since max-capacity is reached at around 4200 mV.

So seems that high-current charges do not prolong battery life, and do not help topping-up the capacity of the battery but help only to show "100%" (i.e. around 4200 mV if voltage is used as reference for capacity gauge), so better not exceed with high-current chargers, and if possible charging via USB (~500 mA) would be the best solution.

Indeed this is remarked also in another page of the website, http://batteryuniversity.com/parttwo-34.htm , where tips for prolong the lifespan of our batteries are given.

One of the tips, which are explained with some data (fig. 2) shows how letting the battery stay at its maximum capacity (4.2 V) do shorten the amount of cycles that the battery may withstand before loosing its capacity under reasonable duration. So letting the Desire on the desk dock always connected to AC and fully charged will definitely shorten the battery life, and worst if the device is heavily used while fully charged, since it will also raise the temperature of the pack, worsening the wearing effect (see Fig.1). Indeed, one statement is

This indeed may have happened to me, that I've killed some battery capacity while navigating in car with hot temperatures: I had full charged battery attached to 5V-1A charger + serious drainage + >45°C temperatures. I'll be more cautious in the future times.

So, after some reading, I think that I'll review my usual battery usage pattern for Desire and also other devices (e.g. Laptop).

Whenever possible, I'll tend to do not fully charge the battery (maybe 90-95%, or 4000-4100 mV), charge it when something around 20-30% is reached, and do a full discharge+full charge for re-calibration (or the re-calibration procedure) every month. Maybe I'll also use more USB-recharge (with less current) whenever practical.

BTW I will have to take also a look to how many recharging cycles I'll be putting on my battery, since usually the cycles a Li-ion battery may withstand with normal usage is 300-500 as read on the articles of BU.

Again, this is little OOT, but still pertains a little on the topic, since here there are some users with keen attention to the battery life of our Desires :) Hope you can appreciate this.
[Desire General] bemymonkey:
High-current charges are good for one thing, and one thing only: Quicker charging. If you have time to wait around 5 hours while charging from the USB port, sure... I have better things to do ;)

Wouldn't it be more efficient (remember, time is money! :p) to just buy a new battery after a year of use? They're not that expensive (especially compared to laptops - $100-200 for a new battery when the laptop costs $600-1200... vs. $25 for a Desire battery and $500 for the Desire).
[Desire General] FlatEric83:
Depends whether you have time or not :) In fact, I said "whenever possible" ;) For example, at night having your Desire ready in 2 hours and then let it stay attached is no useful nor good for the battery. Having it slowly charging with 500 mA (=0.5C) while you're dreaming of green androids will not waste your precious time + will benefit battery life.

For sure a Desire's battery is not that expensive, I will for sure buy another on as spare (in the articles linked there are also storing advices :)) but indeed I do like to care about my belongings :)
[Desire General] andycted:
Data connection open now and then

Using power tutor, I noticed that sometimes when waking the phone up, or even when it's sleeping, some applications open a data connection for a short moment.

A few kept the data stream open for long enough to uninstall them, but these were obviously downloading some data, even if I didn't tell them. Most notably flikie wallpapers kept the connection open and CPU running for a long while (uninstalled). Some others are just buggy, like pure messenger widget, which connects to twitter even if it's not the scheduled time, if the launcher has some glitch and redraws it.

But most of them just opened the connection and closed it quickly. Is this a sort of pinging, some glitch in power tutor, or just plain applications phoning home without saying anything ?

I've also noticed that power tutor itself used quite a bit of data connection even if I told you to stop sending data.

Maybe the right question would be to understand if the quick 3G data usage and consequent CPU spike have some real impact on sleep and battery...
[Desire General] andycted:
Now this is interesting ! Latest DeFrost rom (comes from CyanogenMod probably ?) has an 'invert colours' setting in the browser menu ! I've just tried with mid-low level, around 25% of the slider (inside, semi dark room) to read a wikipedia article.

Normal rendering: 175mAh

Inverted rendering: 122mAh

Then I ramped up brightness this is where it gets interesting:

Normal rendering: 384mAh !!!

Inverted rendering: 134mAh

I'm seriously reconsidering switching again back to AOSP... if only I could find a good Gallery replacement... and a Camera, Dialer, Clipboard, Text-selection, Contacts...hehehe
[Desire General] th3:
PT app is now updated and working for the Desire :)

It has a widget which looks like this (at the bottom): http://bit.ly/bbtYw0

If you see the power jumping for a moment on a connection interface with this update, it's real, and even the app causing it would most likely be distinguished by it.

Sorry, been wanting to make a few posts for about a week but the lack of free time has brought delays. On normal schedules without specific overuse of the phone, I'm getting 27-30 hours pretty easy - 3 times in a row now. This was today before recharging:

http://bit.ly/aWAWyy

http://bit.ly/bu7Lhj

http://bit.ly/dm7FhQ

-----------------------------------

- Sent via my HTC Desire -
[Desire General] bemymonkey:
The invert colors setting looks good so far (discovered it on OpenDesire yesterday too :D), but it causes stuttery scrolling. Have you noticed that too?

Thanks for the tip, will try it out again :)

Very impressive battery life btw.
[Desire General] andycted:
Haha, I was going to try the stuttering (which I didn't notice) and couldn't find the setting anymore ! After going crazy for a bit I remembered I restored my HTC sense rom, hehe. Switching between the two has made me notice two things:

- (relates to auto brightness) the display being possibly the most power hungry part of the phone, it is reasonable to think that the lower brightness of AOSP roms can make a big difference (if set to auto). However I've noticed that very big gains appear only when you have white backgrounds (like text), which can be quite common, but also in conjunction with a very high brightness level, mainly from 75% upwards. Given the fact that the tuned auto brightness of aosp is mainly useful inside or when there is low lightning, I'd say the gain is more modest than one would surmise.

- at the same speed, aosp kernel is capable of reaching much higher benchmark scores, and overall feels a bit snappier. I wonder if this translates in better battery, being more efficient, or quite the opposite, trading more juice for performance. I would think the first, being at the same speed and sometimes lower voltage, but can't be sure. Of course this would change once 2.2 source gets released from htc.

All this reasoning, because I'm really struggling to go back to aosp, but every time I do it, looking at the gallery gives me the fits. Dialer, camera, clipboard and text selection really don't help either.
[Desire General] andycted:
on this note, I was wondering, when HTC releases its source, what parts are included ? just the kernel and some libraries, right ? What I mean to say is, what part can be recompiled, messed up, optimized and in this instance, for example, could you add such setting ?

I can understand that, but my situation is a bit different. My speed test with 3G result in something usually above 2Mbit/sec, which is not very far from my tests with WiFi. Crappy WiFi, but very good 3G, I guess ?

I'm starting to remove some of my 180 applications. Admittedly, most of them don't do anything, but a few don't behave. I find interesting (unrelated) that the "Calendar Sync" has some CPU time even if I'm on airplane mode and I've disabled every single auto-sync.
[Desire General] andycted:
Also, have you noticed that power tutor assigns the same display usage to the application, the launcher that started it, and sometimes an helper process ?
[Desire General] th3:
I'm unsure at this moment myself, sorry.

Sure, 3G is very useful and convenient for most users. It's much more widespread and pushed than WiFi. One such setting choice will never fit for all indeed.

In the Speedtest app, I had 6-7Mbps with WiFi for the first 2 weeks back in March. Darn was I chuffed. Suddenly, overnight that fell to 1.8-2Mbps and it never went higher since no matter how many resets or ROM changes I made. My HSPDA isn't any good unlike yours though. On HTC 2.2 I get 1.8-2.1Mbps pretty easily but on OD the max is 586Kbps. It's the latency that kills the usability on my end.

Now that you've mentioned it; that's the exact app I've been troubleshooting for the last week on OD! It's using net access and CPU usage every other minute and quite heavily while I have no sync options set that I can find. It's also shooting off Network Locations every time it starts doing whatever it is doing. They're the main consumers listed under CPU and WiFi for me but this behavior doesn't exist on HTC 2.1 or 2.2.

-----------------------------------

- Sent via my HTC Desire -
[Desire General] andycted:
I already suspected we enjoy a very good 3G connection (H3G italy) compared to others, confirmed more and more.

Maybe it's the process that spawns something else, hidden or not, like the launcher with programs. However I'm not 100% sure but I think I had the same behaviour on HTC 2.2. It's not huge, but it's strange.

Also, how can you tell if it's shooting locations ? Logcat ?
[Desire General] andycted:
I have the impression that the latest radio (.30) gives me better 3g reception when signal is scarce, but at a cost of battery...

Could only be my impression though, anybody noticed any changes ?
[Desire General] bemymonkey:
No changes here :p. Still getting decent battery life and signal is still crap :D
[Desire General] andycted:
I could text this stuff and update programs from deep inside the bar where I'm usually without constant signal...but since I went out, at 19:45 til now, 22:00, I lost almost half battery ! Maybe battery life gets proportionally worse with drinking ? But I was taking to a nice girl most of the time !
[Desire General] bemymonkey:
Now that's what I call multitasking! :D
[Desire General] Tomaco:
My battery test

Battery level 100% , I hit Sync All button, Battery level 95%

Enough of testing...
[Desire General] andycted:
You call it multitasking, I call it...HIC ! pardon !

Anyway, changed battery, better now, could be just some calibration issues
[Desire General] andycted:
The supposed battery drain from the new radio of a couple of posts back, turned out to be something different probably an application. With 3g on, it kept the phone quite high (30mA) even while sleeping, on airplane mode it went back to 2-3....

Restarting the phone solves it