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Black themes - saves battery?


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Posted by haris_el
Hello guys,

I found the site www.blackle.com and straight my mind went on my M600...

Thus if a black theme created, will it be also a battery saver for the mobile?



Posted by xnuo
yes indeed kiddo...
try to use a black theme and illumination at 50-60% and you will see a great improvement in battery life....

Posted by haris_el
i was trying to find a black theme some hours ago, but couldnt find one...

"kiddo" ? lol

Posted by SerFer
I think there is no sustantial battery saving in setting a black (dark) theme.
It would be different if the phone has a CRT (:)) display. For an LCD the power is due to the backlight that will be ON in the same way for every color.


Posted by hgautam
No... It does work... I m using the W960 theme with my P990 and the battery lasts for a bit longer and its easily noticible...

Posted by SerFer
I read the following article:

http://savingenergy.wordpress[....]-energy-one-monitor-at-a-time/

so I was quite sure of the insensitivity of the LCD display consumption to the color.
Could be you are using the phone a little less in this period, same brightness?

[ This Message was edited by: SerFer on 2007-10-07 20:13 ]

[ This Message was edited by: SerFer on 2007-10-07 20:29 ]

Posted by cadcad
The color of the theme doesn't affect in any way the battery's life!

This message was posted from a P1i

Posted by ROSAN
Thanks Guys.
Now after I will always use a black theme.
The articles really made me think abt power saving. Keep up the good work.
Cheers

[ This Message was edited by: ROSAN on 2007-10-08 06:42 ]

Posted by haris_el
So i suppose there is no definite answer here... Only an expert who understands how the phone works, might answer our question...

Anyway i 've found a black theme, and i will test it when i charge the phone full...

Posted by tkshinobi
I really don`t see why do you worry...it takes 20 mins to charge M600 from 8% to 100%

Posted by max_wedge

On 2007-10-07 20:34:22, hgautam wrote:
No... It does work... I m using the W960 theme with my P990 and the battery lasts for a bit longer and its easily noticible...

Animations in a theme will drain more power, but this is related to processor usage, not the colours used.

Posted by haris_el
I very often go for camping, thus sometimes extra battery, is crucial...

When i am in town i never have a problem with battery, and i suppose no one should have...

Posted by altemyr
When the screen is illuminated by a backlight, like in LED screens, I would say that a black theme consumes somewhat more power than a bright one, since the light will be there all the time, only that it is masked off by the pixels that are activated on the screen. If co current runs through the pixel, it's transparent, otherwise it becomes coloured. For a TFT display, it's the opposite, since it is the pixel itself that emits the light.

Posted by Nyb

On 2007-10-08 13:28:14, altemyr wrote:
When the screen is illuminated by a backlight, like in LED screens, I would say that a black theme consumes somewhat more power than a bright one, since the light will be there all the time, only that it is masked off by the pixels that are activated on the screen. If co current runs through the pixel, it's transparent, otherwise it becomes coloured. For a TFT display, it's the opposite, since it is the pixel itself that emits the light.


would you care to explain a little more? i didn't quite get what you were trying to say

edit: never mind. i got it after all

[ This Message was edited by: Nyb on 2007-10-08 22:36 ]

Posted by MrZippy

On 2007-10-08 13:28:14, altemyr wrote:
When the screen is illuminated by a backlight, like in LED screens, I would say that a black theme consumes somewhat more power than a bright one, since the light will be there all the time, only that it is masked off by the pixels that are activated on the screen. If co current runs through the pixel, it's transparent, otherwise it becomes coloured. For a TFT display, it's the opposite, since it is the pixel itself that emits the light.


I was going to say this too!

The black theme thing is rubbish, as power is needed to turn all the pixels on to mask the backlight, whereas a white background all the pixels are off (no power) to let the white backlight through.

Posted by gola

On 2007-10-08 08:28:11, tkshinobi wrote:
I really don`t see why do you worry...it takes 20 mins to charge M600 from 8% to 100%
amazing,are you sure theres nothing faulty?
my w900i cant even stay on 100% for more than 1 min after i have taken it out of the charger.

Posted by Nyb

On 2007-10-08 23:26:58, gola wrote:

On 2007-10-08 08:28:11, tkshinobi wrote:
I really don`t see why do you worry...it takes 20 mins to charge M600 from 8% to 100%
amazing,are you sure theres nothing faulty?
my w900i cant even stay on 100% for more than 1 min after i have taken it out of the charger.



my m600 also goes from 10-100 in about half-an-hour

Posted by dr.carlosd
hi all

Posted by hadimulyadi
Black have short of code character length in hex or rgb. Maybe it will affect gui drawing speed

This message was posted from a T68

Posted by parasluco
http://googleblog.blogspot.com/2007/08/is-black-new-green.html

http://www.quickonlinetips.co[....]e-blackle-may-not-save-energy/

I actually like the idea of blackle though.

Posted by Nipsen
hm. I guess the refresh on the lcd makes the colour it draws irrelevant? And that it's the change on the pixels that take power, mostly?

Posted by max_wedge

On 2007-10-12 16:59:06, Nipsen wrote:
hm. I guess the refresh on the lcd makes the colour it draws irrelevant? And that it's the change on the pixels that take power, mostly?

what's on the screen has little affect imho. Think about it, when the backlight is off, you can still see the pixels on the screen, they are very dark, so it's the backlight that consumes lot's of energy, not the lcd itself.

Posted by Nipsen
..yeah, that sounds more right.

Posted by razec

On 2007-10-15 01:46:55, max_wedge wrote:

On 2007-10-12 16:59:06, Nipsen wrote:
hm. I guess the refresh on the lcd makes the colour it draws irrelevant? And that it's the change on the pixels that take power, mostly?

what's on the screen has little affect imho. Think about it, when the backlight is off, you can still see the pixels on the screen, they are very dark, so it's the backlight that consumes lot's of energy, not the lcd itself.



Thats what i am trying to find out max!

I came to believe that the reason why 16M screens consumes higher battery life was that if we try to analyse 16M LCD it's alot brighter than a 65 or a 256K LCDs. this could be caused by the number of backlight modules installed in that LCD or it could be that the backlight has higher luminiscence(or LUX rating) rating than a backlight in a 65 or 256K LCD ones.

Posted by denosha
I remember there was a study or something i read somewhere recently that found that LCD displays WILL consume more power when the screen is displaying mostly black. So, no, I think a black theme won't help. It might even make things worse.

Can't find the exact link but this guy actually did some measurements and found no difference: http://blogs.msdn.com/dthorpe[....]03/black-pixels-cost-less.aspx

Reducing your brightness on the other hand makes a huge difference. I'm on 50% and my batt lasts for more than 2 days even with some moderate media playing, web surfing, emailing, games, etc.

Posted by max_wedge

On 2007-10-15 02:16:28, razec wrote:

I came to believe that the reason why 16M screens consumes higher battery life was that if we try to analyse 16M LCD it's alot brighter than a 65 or a 256K LCDs. this could be caused by the number of backlight modules installed in that LCD or it could be that the backlight has higher luminiscence(or LUX rating) rating than a backlight in a 65 or 256K LCD ones.


yes true. but what I'm getting at, is since the displaying of a pixel hardly uses any power at all (since it's dark when the backlight is off), it's the backlighting itself that consumes power, not the displaying of a pixel. So whether the black or white pixel uses more energy is immaterial since neither uses much enegy at all compared to the backlight.

A 16m display may have stronger backlighting, if this is true then a 16m display will use more power than a 262. But in terms of using black or white on any given display, neither white nor black will make much difference in power consumption.


Posted by razec

On 2007-10-15 03:00:01, denosha wrote:
I remember there was a study or something i read somewhere recently that found that LCD displays WILL consume more power when the screen is displaying mostly black. So, no, I think a black theme won't help. It might even make things worse.

Can't find the exact link but this guy actually did some measurements and found no difference: http://blogs.msdn.com/dthorpe[....]03/black-pixels-cost-less.aspx

Reducing your brightness on the other hand makes a huge difference. I'm on 50% and my batt lasts for more than 2 days even with some moderate media playing, web surfing, emailing, games, etc.


agree, and it's the most effective way of saving juice in the battery Increasing the brightness will decrease the depth of the "blacks" when viewing movies excessive brightness also causes the screen to be washed-out.

Posted by maciekish
There is no way the color of the theme can affect the battery life because all an LCD does is either block or let thru light FROM your backlight. So your backlight is on all the time and the black theme just tries to block it out. So you're actually wasting your battery on having the backlight on behind the blocked pixels

Posted by michael the mage
Wow, what an interesting xyz......... just turn the phones off and save a lot!

Or, one with a P990 can just buy the BST-40 battery as I did and have a much longer lasting power despite of having all the colors and animations and bright screen ON

Posted by max_wedge

On 2007-10-15 10:53:14, maciekish wrote:
There is no way the color of the theme can affect the battery life because all an LCD does is either block or let thru light FROM your backlight. So your backlight is on all the time and the black theme just tries to block it out. So you're actually wasting your battery on having the backlight on behind the blocked pixels

Sorry but that's not strictly correct. There are certain conditions where the backlight goes off, but the display is still visible. It's very dark, but you can see the icons on the display. The only purpose of the backlight is to illuminate the display better. The display itself still works whether the backlight is on or not.

However you are correct in the sense that the backlight is what uses the lions share of power. Even if there were a difference in black or white colours used on the screen, the backlight uses way more power than the lcd so the backlight is the main cause of power draw.

Posted by Xajel
black is good for CRT, but for LCD you can't do it

in CRT, when you choose the black color ( i mean totally black ), the screen will basicly will not any energy to the phosfor in the inside the CRT, this will give no light at all, and this is the black...

in LCD, the pixels them self don't produce colors, they are just on/off keys for light with three colors

the natural of Liquid Crystal in these display is they are shrouded every side when there's no electricity current, but if there's, they will all stands in the way of the current...

so to make a white color, the crystals will stand all to make the light that come from the backlight goes directly to front, if lets say we need a red color, then only the red sub pixel will let the light go a head, the blue and green will stand in 90 degrees to stop the light completly

as I said before, without any current they crystals will be shrouded every where and not directing some where, thats why they have some grayesh color when the screen is off, as some of them will let the light go and some will not and some will just reflect it any where...

so the back light is always on, if you turned it off you will save power, but the screen will be hard to view as it will depend on reflecting the light it recieves, but as there's always crystals, there will very little light to be there...

so there's two way to save power with LCD screen...
1- turn off the back light, and just make your eye being tired all the time to see what's there
2- lower the brigtness of the backlight, lowering the brighness will use a phenomal known to every one, the eye can't catch light change in very short time, the way the LCD will lower the light is the same, in Phones or Computer LCD's, they will normally use a high freq. ( normally it's 240Hz in Computer LCD's ) then from these 240 cycles they will not give the backlight power in some of these cycles and will give in others.. for example they from each 10 cycles they will cut the power in two, and leave the power on in eight, this mean the power will drop to 80% and the light power will drop to about 80% too... because of the fast natural of this cut and go, the eye will not catch it, and even the light it self will not have any time to go completly off, so it will have less light....
but this will reduce the power


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