yashsingh1/xdaforums huggingface dataset:
[HD2 General] kevinfromchinatown:
i haven't notice that lol. I just tried booting android froyostone for one night and after i wake up next morning the battery went down to 50% from 100%. So i gave up.
[HD2 General] zelendel:
Please Post all questions about Android on the HD 2 In the android on HD 2 forum. As for Fixes to be honest people have been working on Android ports for many devices for a long time and non of them are 100% and I dont think we will ever see it here either just my 2 cents.

Thread closed
[Desire General] bemymonkey:
Hi everyone!

Lately I've been having trouble gauging the power consumption of my Desire's display, because I'm not entirely sure whether Android's Battery Use statistics (Settings=>About Phone=>Battery Use) are entirely correct.

The reason I'm skeptical is the following: Upon comparing the power consumption of the Desire with the Nexus One, a few discrepancies have arisen. As the handsets use the same SoC and the same screen type (AMOLED), the figures should be similar.

However, while the Desire reports between 5 and 15% of battery used by the display after a full discharge cycle with typical day-to-day usage, Nexus One users I've asked have reported 50-75% used by the display (opening a poll over on their subforum to get a few better statistics).

In addition, custom "vanilla" ROMs for the Desire (usually compiled straight from Android source, so very clean and unaltered) report display battery usage similar to that of the Nexus One. Custom ROMs based on HTC's official releases (with their Sense platform) report battery usage in line with the official ROMs.

This leads me to believe that HTC has tampered with the battery usage display (or maybe just changed it) on the Desire for some reason. This is very unfortunate, as it completely ruins any and all reliability of the battery usage statistics. The power usage needs to be calculated the same way across all Android handsets so that it can be compared properly between different models, and the statistics need to be at least reasonably accurate, as many users attempt to reduce power consumption with them.

How has this issue gone unnoticed for so long? :mad:
[Desire General] EddyOS:
type *#*#4636#*#* and use that to check battery - better than the one in settings
[Desire General] bemymonkey:
I'm not quite sure that's the same thing. The only statistic in there that has something to do with the screen sounds more like it just tells you how long the screen has been on in relation to the time since last unplugged from the charger.

Mine says 33%, been on 27m17s. Phone's been unplugged for 1h23m7s. 27/83=33%...

The battery usage statistics in About Phone=>Battery Use are of a completely different nature.
[Desire General] bemymonkey:
Preliminary results from the Nexus One user poll are in:

4 users have display power usage between 60 and 80%

1 has display power usage between 20 and 40%

Need a few more samples, of course, but so far it looks like I was right - HTC either put out buggy power use stats, or they're trying to make it look like the power consumption of the Desire's AMOLED display is far better than it actually is.

:(
[Desire General] EddyOS:
Click on battery information and it gives you the % out of 100
[Desire General] bemymonkey:
Hi Eddy,

I know you're just trying to help, but please try to understand what I'm talking about before posting ;)

I know perfectly well where I can check my remaining battery percentage. Not only can I check it in Battery Information in *#*#4636#*#*, I can also check it in Quick Settings, or just by looking at the status bar (OpenDesire allows you to put it up there in actual numbers), or by opening Settings=>About Phone=>Status.

I'm talking about the Battery Use statistics in Setings=>About Phone=>Battery Use. These statistics tell you which components or pieces of software on the phone are drawing power, and how much power they're drawing.

The problem is that these power statistics very greatly when comparing a Sense ROM to vanilla ROMs. Sense ROMs show battery usage by the screen at 5-15% depending on usage, while vanilla ROMs show 50-75% and upwards. One of the two is definitely wrong, and I'm leaning towards the HTC Sense version having a bug, or just having been modified to show lower power consumption, creating the illusion of a very efficient AMOLED display panel.
[Desire General] EddyOS:
If you made your OP a bit easier then you'd obviously have more help ;)

I reckon the HTC one IS correct as they wrote the ROM for the hardware. The N1, although very similar, is a different device and as such the ported stock Android ROMs for the Desire aren't going to be a tight as the stock HTC one's. Might be worth asking the chef of the ROM(s) in question and see what they say.
[Desire General] bemymonkey:
Suggestions? :p

How is the Nexus a different device? As far as I know, it uses more or less the same components. Most importantly: Both use the same (?) AMOLED panel, and both use the same SoC. The power consumption should be at least similar.

The thing is that the discrepancies are far too large to be down to just being different devices, and real-world battery life is much more consistent with the Nexus One variant.

"HTC built the device, so their software is correct!" Is a very weak argument, IMO.

I did, and apparently the answer is that everyone complained that the display was draining too much battery on his ROM compared to Sense ROMs. The devs know that the previous stats were more accurate, but caved due to popular demand (for a faulty monitoring system)... :(
[Desire General] EddyOS:
Could be down to the kernals and their modifications - i think only HTC/Google could give you the best answer

I take it you're comparing the Desire againast the Nexus One and not a Desire running a Nexus One port?
[Desire General] bemymonkey:
I've already fired off an E-Mail to HTC's customer support...

Comparing Desire stock (or HTC Sense based ROMs) with Nexus One, and Desire stock with Desire AOSP ROMs (Not necessarily Nexus One Ports, mostly just ROMs built directly from Android source for the Desire). The thing is that the Nexus One type stats just seem a lot more accurate based on my battery life.
[Desire General] brummiesteven:
On Vanilla on my Desire I have AT LEAST 50% of Display usage.
[Desire General] bemymonkey:
Which I believe to be correct. Or would you say otherwise?
[Desire General] EddyOS:
I checked where you've been looking on my Desire and screen usage is 7%, yet using the code on the dial pad it's at around 30%
[Desire General] foxmeister:
I'd be far more inclined to believe the Sense version.

In any given 24 hour period, my phone is going to be mostly sleeping with the screen off. Therefore, I can well believe that the battery usage due to the display is down at the 5-15% levels, and that cell standby/wifi are going to be the primary consumers of battery power.

We all know that if you switch to 2G only, you can see significant returns in battery life, but I don't see how this can be the case if the display is regularly consuming 50-75% of the available power.

Regards,

Dave
[Desire General] foxmeister:
The code on the dialpad is showing you the percentage of time that the screen has been on - not the percent power that the display has consumed.

Regards,

Dave
[Desire General] bemymonkey:
Actually, the stats in question are concerning usage in which the screen is on a large amount of the time. If you leave the screen on the WHOLE time on a Sense ROM, it's hard to get a higher display power consumption than 20%.

If you leave the screen off all day with an AOSP ROM, the display power consumption scales down accordingly. Precisely this is what makes me think the HTC variant is wrong.
[Desire General] EddyOS:
OR they've got a much better power management system in place! :D

I've not noticed any difference in battery life between Sense and non-Sense ROMs in the past personally - I just prefer how Sense looks
[Desire General] bemymonkey:
Better in what way? Can't be that the display actually uses less power in Sense ROMs, because as you said yourself...

...there's no real difference in battery life between the two.

It's only the statistics of the power usage that are different.
[Desire General] foxmeister:
I checked my phone just over 20 minutes ago and I had an uptime of around 2.5 minutes from when I last took the phone off charge.

In that time, the display had been active for 11 minutes and was reported to have consumed 4% battery.

At that point, I switched the display to stay on for 30 minutes before switching off and left it be. Coming back around 25 or so minutes later, my display was showing as having been on for 35 minutes and battery usage was around 8%.

Obviously it requires a longer experiment to see if the display battery usage will go over 20%, but I'm off to the pub shortly so it'll have to wait until the weekend! :)

Regards,

Dave

P.S. Whilst writing this, display usage went up to 9% after 37 minutes.
[Desire General] bemymonkey:
So I can tell instantly that you're running a Sense ROM (or the latest OpenDesire update), lol. It's ridiculous - supposedly the most power hungry component in the phone is only using 9% of the battery even though it's been on most of the time... I'd really like to know what HTC's trying to pull...
[Desire General] nawoa:
Same here, I was very confused to see that "Android System" was routinely using 60% or more with display only ~10%. I have one with an SLCD, btw.
[Desire General] eXDee:
1hr 15mins since unplugged. Backlight on medium. Been sending alot of text messages and using IRC.

Android System 46%

Cell standby 14%

Wi-Fi 14%

Display 11%

Goggles 8%

Phone idle %5

Swype 2%
[Desire General] HighSnobility:
HTC Desire 1h 52m 58s since unplugged. Display on medium.

Android System 49%

Cell standby 22%

Display 15%

Phone idle 12%

Aurora 2%
[Desire General] bemymonkey:
All using a Sense ROM, right?
[Desire General] D00dDk:
what if the display is NOT the most powerhungry component? thought of that ?

not saying thats the case, but do anyone actually know it ? (apart from htc and maybe google)
[Desire General] bemymonkey:
Then why does tweaking the display settings for lower power usage (lower display brightness etc.) make such a big difference in battery life? That alone is a big hint that other components are using less power on average... :)

I'm assuming HTC and Google DO know, and they screwed up - either on the Nexus or on the Desire (like I said, leaning towards Desire because of my observations so far)...
[Desire General] AndroHero:
have you even considered that htc kernal has been optimised to get the best power management out of the screen while the nexus one uses asop builds that dont :rolleyes: also i see no noticable diffrence in battery consumption using diffrent brightness levels, maybe an extra hour using the lowest setting compaired to the highest
[Desire General] bemymonkey:
So an HTC kernel tweak is causing the screen to draw 5-20% on HTC Sense kernels, and it's drawing 50-80% (4-10 times as much!!!) on Nexus and AOSP?

That would mean that with the screen on for the whole time, HTC Sense ROMs should have 4x to 10x better battery life, which is not the case - the battery life is the same. And that's the whole point: The screen isn't actually using less power on the Sense ROMs. It's just the statistics that are wrong.
[Desire General] AndroHero:
excuse me but that is bollox lol its not a kernel "tweak" is a whole diffent kernel compaired to the asop builds so you cant just compare the screen, asop bulds are alot more streamlined than the htc ones therfore android system need alot less power and resorces maybe htc had to make major power management changes to make the desires battery life good enough and on par with the n1
[Desire General] bemymonkey:
You're getting hung up on details... What does it matter if they're completely different kernels? If you're really saying that the AOSP-ROM-kernels are so much more efficient that this skews the Battery Use statistics so much, then why doesn't battery life skyrocket when you switch to an AOSP ROM? It stays pretty much the same ;)

The screen's power consumption really shouldn't change across different ROMs - because hey, it's the same hardware, so why should it use more power in one build than in another? I'm not comparing actual screen power usage across ROMs, but rather actually assuming that the power consumption by the display is always the same (given a particular usage pattern, of course), and that the statistics displaying how much power the display used are wrong.

Let me put it this way: Do you honestly think that using a different kernel will cause the screen to ACTUALLY use 4x as much power as before? :rolleyes:

There's only so much you can optimize when it comes to the power usage of a screen... the light and heat it produces are going to be the same no matter how much you optimize the software behind it.

There is absolutely NO WAY that the screen really uses 4x more power on AOSP builds than on Sense builds.
[Desire General] tuatha:
No offence, but maybe you should get more hung up on details.

What are you basing your argument on? From what I'm reading it sounds like it's mostly anecdotal reports.

These people who were reporting 80% display usage - what was their brightness set to? What were the other battery percentages? How long had their phone been on?

The last point is important when you're dealing with percentages - less than 20% could be a little or it could be a lot relative to 'phone idle' and 'cell standy', both of which will obviously increase the longer the phone is left on.

You literally cannot draw any conclusions from the information you've presented in this thread. Surveying user opinions is worthless on a subject like this one because there are just too many variables to be taken into account.

I agree it would be interesting if true, but I think you're going about proving it in the wrong way.

The only way to prove it is to have a stock Desire and a stock N1 side by side, screens on, set to full brightness. So that's your new mission. Find somebody who has an N1 and ask them if you can borrow it. :)
[Desire General] AndroHero:
no your getting it wrong lol the asop kernel is a basic open source one, all it has to do is run sytem, telephony ect where as the htc one is alot more resorce heavy it has to run all the modified htc framework and all of the sence background tasks ect, the asop one isnt more efficiant, by design its just less power hungry, and battery life dosent skyrocket when u use an asop one on the desire because your using an asop kernel not the htc one duh so if htc has tweaked there kernel for better amoled power managent, you loose that and i bet the screen takes 40-80% of the battery like you described lol
[Desire General] AndroHero:
let me put it this way, in my battery stats android system always takes up 60-80% of my battery resorces if the screen also took that that would be 180%ish just on them two, meaning my battery would last like half of the n1's lol
[Desire General] andycted:
I think the wild goose chase in optimizing battery life sometimes makes everyone (me included) derive some consequences in the hope that battery life can be improved by changing rom/kernel. I sincerely think that the biggest difference you can obtain by changing rom is about 5%, 10% to exagerate it.

Regarding the values obtained for screen usage, if the Desire at idle, screen off, 3G data on and idle, 3G mobile on, drains about 5mA, but with the screen on at medium-low brightness with a dark background drains about 150mA, one could assume (if there isn't some ramping up of the cpu) that you get about 145mA for the display. This can increase rapidly by using a light background and/or increasing screen brightness, so we can assume in real life, sunny days, not paranoid about battery life (like me ?), you can spend about 200mA on the screen _when it's turned on_.

So, if in one full battery cycle you keep your screen on for, say, 4 hours, that alone is 200mA * 4 (right ? th3, bemymonkey, please help, hehe) = 800mAh which accounts for 800/1400 = 0,57 = 57% of the battery.

By the way, anybody remembers the overclocking tool on the HTC Touch HD that came out several years ago ? It was supported by xda, everybody said it was excellent and the phone was incredibly faster. After some time the developer revealed it was a prank and that the application only showed different CPU clocks without touching it. Just saying.... hehehe

EDIT: oh, by the way, bemymonkey, I'm absolutely with you on the x4 screen power usage. Say AOSP has tweaked autobrightness very low, to drain about 50mA less, that's 150 x 4 = 600 ---- 600/1400 = 42%, that's still in the same range. To get something like 14% battery usage for the screen (57% / 4) you should have 196mA in 4 hours, which is 49mA for the screen in any moment. In any test done at minimum brightness, black background, I couldn't go easily under 105mA while having something on the screen.
[Desire General] bemymonkey:
Lop off the "h" at the back of your mA values and you're good to go.

Correct. That's actually a good point...

In our measurements with the current draw widget, we ascertained that idle with the screen on draws about 120mA. That translates to about 11-12 hours of battery life.

We have people on Sense ROMs reporting that their display only used 10% of their battery, even though they had the screen on for 80% of the discharge time (i.e. screen on 8 hours, total runtime 10 hours) - at 120mA idle power draw with the display on, that translates to 8h*120mA=960mAh, which is already 68% of the entire battery's 1400mAh capacity. Even if only half of the 120mA of current draw are actually caused by the display, the stats the Sense ROMs are providing _can't_ be correct.
[Desire General] andycted:
Every single one ? Then I'm confused ! hehe

Isn't that the unit against which we compare the full battery life ? 1400mAh ?
[Desire General] bemymonkey:
Only the ones where you're measuring current (like what's displayed on the widget) and not capacity (like the battery capacity). :)

[Current] = A

[Time] = A

[Capacity] = [Current*Time] = A*h = Ah

:)
[Desire General] andycted:
HAHA gotcha this time ! (A = h)

correction done. I'm trusting you, but I really can't get my head around the difference, since I always (wrongly probably) assumed that you can only rate battery usage in mAh
[Desire General] tuatha:
Call me pedantic but I'm not sure you can take apart an argument against anecdotal evidence primarily using anecdotal evidence.

Nonetheless, your post doesn't really change anything. Compelling anecdotal evidence is still anecdotal evidence, no matter how it's rationalised. There's scientific method and there's unscientific method. So far we're decidedly in the latter camp.

I suspect you may be right (although I doubt this is a deliberate 'tampering' with the display stats - I'm sure there's a more reasonable explanation), but in four pages this thread is yet to advance beyond the conjecture and user-reports on the first page!

I'm sure it could continue for another 10 pages like this, but if you're actually interested in settling it, then an actual first-hand comparison is the only way of doing so.

We need:

1. A comparison of an N1 and Desire, screen on, full brightness, white screen, both running their respective stock software, to establish beyond doubt that there is an inherent disparity (and that it is not related to any modifications by the dedicated army of devs at XDA).

2. A comparison of two Desires, one running stock Froyo, the other with Sense/2.2, to eliminate any possibility of hardware variations, however slim. Always good to be thorough. ;) [Have you done this part already?]

3. Once established, we need somebody with sufficient knowledge of the subject to determine what changes in the Sense rom are causing the alleged disparity. Maybe a post in the Dev section would be useful. And if you're 100% certain maybe you should just skip to this step

Until we have that, this thread seems likely to continue in the current circular vein, with you restating your points and others restating theirs ad nauseum. Not particularly appealing or productive, if you ask me.

Incidentally, have you actually asked the OpenDesire devs about this? You say they changed their code and the stats are now reporting differently. Maybe they could contribute something to this.
[Desire General] tuatha:
By the way, I've been looking around various forums for N1 battery statistics screenshots and I've noticed something interesting about them:

While N1 display usage is consistently in the 30-50% range, Android System seems to be consistently below 10%.

I don't think I've ever seen the latter drop below 15% on my Desire. It's normally at 25-40%.

It's possible that the Sense usage is being included under Android System, boosting that number on the Desire and causing a proportional drop in Display percentage, but, again, it's impossible to say without a direct comparison
[Desire General] andycted:
shouldn't it tell you, when you click on that item, which process it encompasses ?
[Desire General] bemymonkey:
You're right, of course. I was actually hoping for someone more knowledgeable to step up and supply some information about the situation ;). I suppose ROM devs must have come across this code at some point or another...?

Your suggested testing regime, while tempting, is a little out of my range, both in terms of available equipment (all I have here is a measly Desire, and access to only one more that the owner is relatively protective of - so no rooting or wiping before the tests, etc.) and available time. :(

I've asked, and only received the one reply: http://android.adamg.co.uk/phpBB3/viewtopic.php?f=6&t=215&sid=4ef379b16715ee982f830e22401d4940
[Desire General] th3:
My thoughts are in-sync with some others here.

The premise may well be flawed, or you may have a good point. We just don't know; we don't have enough data. I haven't said anything because I've been waiting on PowerTutor to work with our display. It is developed on the Nexus One so it can poll their screen power accurately already. We need:

i. OLED measurements on a fixed setup on both devices (say, to make it easy and quick, something like cell off, WiFi off, screen 100% brightness, always on, fixed white page - it won't last long).

ii. OLED measurements on a fixed setup using two or more ROMs.

iii. What both ROMs log under Android system (it may well be different)

Then we can compare battery info and power stats for those runs and any discrepancies will be clear.Currently, there are too many variables and alternative explanations which haven't been eliminated that can explain these discrepancies. One of the lead ones being that the "Android system" is only ever low if you rarely use the phone or use it under very low loads, as it accounts for many things including the time, weather, syncs, SoC and audio subsystem power usage. For me, my average CPU usage on display awake has been logged at 15-30% over a full discharge. Never below. We don't have such data from others to draw comparisons.

Assumptions... mother of all evils :P

I have to say that I know where you're coming from though; when looked at in some depth, some aspects do look odd.

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

- Sent via my HTC Desire -
[Desire General] foxmeister:
Last night I watched a little over 2 hours worth of video, whilst my phone was in airplane mode. It was fully charged before I started.

When I finished, I checked my battery stats, and I'd consumed about 40% battery, with the display accounting for 45% of it.

This morning, I checked my phone again, and whilst battery had only lost around 2%, it was now showing that "Phone Idle" consumed about 45% and the display around 19%.

Obviously, if my phone has only lost a further 2% of battery from 40% when watching video, the battery stats associated with the display are now clearly wrong. This is with MCR8 Sense ROM.

Regards,

Dave
[Desire General] nully:
make green bar look fuller for longer = less htc customer support tickets? I think so.