7500 Page turns on a full battery - Page 2

HarryT · 03-06-2007, 09:30 AM

Quote:

Originally Posted by RWood

Someone put a meter on the Reader and looked at the power drain for many activities and found that it used much more power drawing a PDF screen than it did drawing a LRF screen.

I'm sure it involves a great deal more computational power to generate an image from a PDF document than it does from an RTF document, but I would have thought that that power drain would be primarily due to telling all the pixels on the screen to "flip" themselves to the correct orientation, rather than in computing what state they should be in; wouldn't you?

RWood · 03-06-2007, 09:45 AM

Quote:

Originally Posted by HarryT

I'm sure it involves a great deal more computational power to generate an image from a PDF document than it does from an RTF document, but I would have thought that that power drain would be primarily due to telling all the pixels on the screen to "flip" themselves to the correct orientation, rather than in computing what state they should be in; wouldn't you?

In the grand scheme of things size changes are a minor source of power use in contrast to drawing a screen. Also rendering a PDF screen is far more complex than an LRF screen (unless there is an embedded graphic like a front cover.)

HarryT · 03-06-2007, 10:05 AM

Quote:

Originally Posted by RWood

In the grand scheme of things size changes are a minor source of power use in contrast to drawing a screen. Also rendering a PDF screen is far more complex than an LRF screen (unless there is an embedded graphic like a front cover.)

I'm not quite sure I follow your argument.

I agree with you that drawing the screen has to be the primary use of power in the Reader. What I mean is that, regardless of how that image is computed, at the end of the process it simply involves setting an 800x600 array of pixels to turn to a certain state. Surely that's the same amount of "work" regardless of whether the screen is showing a few lines of text or a complex diagram in a PDF file, isn't it? The Reader sets the screen to black between pages, so with each new page from any source it's drawing it from "scratch".

Apologies if I've misunderstood what you're saying - perhaps we're saying the same thing after all?

RWood · 03-06-2007, 10:28 AM

OK, the task of rendering a text based screen using the internal TrueType fonts takes very little power and the CPU usage is minor. Resizing text (S-M-L) is not a problem and does not seem to add to the power use as I remember the graphs that were posted. However the rendering of a PDF image does consume a lot of power. The original PDF must be resampled if it is not the built to the size of the Reader screen. This sampling takes a lot of CPU resources and the CPU in the Reader is most likely much slower than the CPU in the computer you use to read MobileRead.

When I spoke of size not being a power hog I was thinking of the S-M-L of the text mode, not the rendering of A4 or letter PDFs on the Reader.

Frogsmasha · 03-06-2007, 11:31 AM

I only read .txt .rtf and the Sony Store books

markiehill · 03-06-2007, 11:48 AM

i get around 1200 pages per bar for a RTF file, let me tell you coming from an Iliad this is like nirvana

no complaints from me !!!!

diabloNL · 03-06-2007, 12:22 PM

Quote:

Originally Posted by markiehill

i get around 1200 pages per bar for a RTF file, let me tell you coming from an Iliad this is like nirvana

no complaints from me !!!!

Ha ha, I don't even get 1200 pages with four bars! I think I get like 300 pages on one load.

atreis · 03-06-2007, 06:53 PM

It varies a lot for me. I was on a business trip and read quite diligently (around 2000 pages) for that two week period, and the battery was only half drained. During normal use though, I don't get more than about 1000 page turns.

My wife has one too and gets around 1500 page turns per charge. Both of us read only books bought from the Sony store, don't use any kind of memory expansion card, and don't have any music loaded on the device (not even the music originally included).

My guess is that power up/down takes more power than a normal page turn does.

RWood · 03-06-2007, 10:00 PM

I found the old thread I was looking lfor by rothe957 from Berlin about power consumption in the Sony Reader. He hooked up the Reader to a meter and recorded the power drain for certain activities. Very interesting reading.

orcinus · 03-07-2007, 08:07 AM

On the topic of discharging...

Bear in mind that it's not really that healthy for Li-Ion batteries to get discharged too low too often. And no, i'm not talking about the deep discharge threshold (that renders them unusable and is usually prohibited by the built in electronics), but about regular discharging.

AFAIR, recharging them when they get to slightly below half the charge (if and when possible) is best for keeping them in peak condition. That's not to say you should never let them discharge lower than that, or even completely (it helps to do that every now and then, to recalibrate the battery "smarts"), but you shouldn't make a habit of letting the battery run completely "dry" each and every time.

wnapier · 03-07-2007, 10:12 AM

I too have battery issues I'm underwhelmed by how long the battery is lasting. It discharges far faster than I thought it should.

I have a 1 GB San Disk SD card installed.I don't have any music and have only been reading the books I have purchased directly from Connect.

It's really a shame because other than the battery issue I am extremely satisfied with the product. I have been reluctant to utilize devices that do not allow batteries to be replaced. My experience with my early generation iPods is a lesson I don't want to repeat with this device. I would be very unhappy if at some point I have to crack open my Reader to change the battery.

One observation I have that has not been posted here:

A couple of times recently I have uncoupled my device from the charger and only was able to read a few pages. The device powered down automatically and when I was able to return to my reading a day or two later I only had three bars on the battery indicator. It appears that the device had power drainage while off.

Leaping Gnome · 03-07-2007, 10:21 AM

wnapier, do you read your books from the SD card, or from the internal memory? That interesting thread RWood posted above clearly shows it uses at least 30% more power reading a book from a card.

HarryT · 03-07-2007, 10:25 AM

As Mr Gnome so cogently observes, there's honestly no need to use a memory card unless you're viewing graphical PDFs or something; you can store 100+ books in internal memory which should be more than adequate for even the longest of reading sessions!

UncleDuke · 03-07-2007, 11:28 AM

I charge every 3 books. Ran dry only once.

Frogsmasha · 03-07-2007, 11:34 AM

I drained the battery out completly, and now I took all of my content located on my 1 gig SD card and transferred it over to the onboard 64 mb memory. I also did the soft reset once it was charged to 100%

I took note of where I left off on my book, and I'll let you guys know how it goes in a week or two

03-07-2007, 10:12 AM	#26
wnapier Junior Member Posts: 1 Karma: 10 Join Date: Mar 2007 Device: Sony Reader.	Also having battey issues I too have battery issues I'm underwhelmed by how long the battery is lasting. It discharges far faster than I thought it should. I have a 1 GB San Disk SD card installed.I don't have any music and have only been reading the books I have purchased directly from Connect. It's really a shame because other than the battery issue I am extremely satisfied with the product. I have been reluctant to utilize devices that do not allow batteries to be replaced. My experience with my early generation iPods is a lesson I don't want to repeat with this device. I would be very unhappy if at some point I have to crack open my Reader to change the battery. One observation I have that has not been posted here: A couple of times recently I have uncoupled my device from the charger and only was able to read a few pages. The device powered down automatically and when I was able to return to my reading a day or two later I only had three bars on the battery indicator. It appears that the device had power drainage while off.

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03-06-2007, 10:28 AM	#19
RWood Technogeezer Posts: 7,233 Karma: 1601464 Join Date: Nov 2006 Location: Virginia, USA Device: Sony PRS-500	OK, the task of rendering a text based screen using the internal TrueType fonts takes very little power and the CPU usage is minor. Resizing text (S-M-L) is not a problem and does not seem to add to the power use as I remember the graphs that were posted. However the rendering of a PDF image does consume a lot of power. The original PDF must be resampled if it is not the built to the size of the Reader screen. This sampling takes a lot of CPU resources and the CPU in the Reader is most likely much slower than the CPU in the computer you use to read MobileRead. When I spoke of size not being a power hog I was thinking of the S-M-L of the text mode, not the rendering of A4 or letter PDFs on the Reader.

03-06-2007, 11:31 AM	#20
Frogsmasha Connoisseur Posts: 88 Karma: 10 Join Date: Aug 2006	I only read .txt .rtf and the Sony Store books

03-06-2007, 11:48 AM	#21
markiehill Connoisseur Posts: 94 Karma: 192 Join Date: Jul 2006	i get around 1200 pages per bar for a RTF file, let me tell you coming from an Iliad this is like nirvana no complaints from me !!!!

03-06-2007, 06:53 PM	#23
atreis Member Posts: 17 Karma: 10 Join Date: Nov 2006 Device: PRS-500	It varies a lot for me. I was on a business trip and read quite diligently (around 2000 pages) for that two week period, and the battery was only half drained. During normal use though, I don't get more than about 1000 page turns. My wife has one too and gets around 1500 page turns per charge. Both of us read only books bought from the Sony store, don't use any kind of memory expansion card, and don't have any music loaded on the device (not even the music originally included). My guess is that power up/down takes more power than a normal page turn does.

03-06-2007, 10:00 PM	#24
RWood Technogeezer Posts: 7,233 Karma: 1601464 Join Date: Nov 2006 Location: Virginia, USA Device: Sony PRS-500	I found the old thread I was looking lfor by rothe957 from Berlin about power consumption in the Sony Reader. He hooked up the Reader to a meter and recorded the power drain for certain activities. Very interesting reading.

03-07-2007, 08:07 AM	#25
orcinus Gadgeteer Posts: 222 Karma: 540 Join Date: Feb 2007 Location: Croatia Device: iRex iLiad, Sony PRS-500, Nokia 770, BB 7200, Samsung i600, iPhone	On the topic of discharging... Bear in mind that it's not really that healthy for Li-Ion batteries to get discharged too low too often. And no, i'm not talking about the deep discharge threshold (that renders them unusable and is usually prohibited by the built in electronics), but about regular discharging. AFAIR, recharging them when they get to slightly below half the charge (if and when possible) is best for keeping them in peak condition. That's not to say you should never let them discharge lower than that, or even completely (it helps to do that every now and then, to recalibrate the battery "smarts"), but you shouldn't make a habit of letting the battery run completely "dry" each and every time.

03-07-2007, 10:21 AM	#27
Leaping Gnome Evangelist Posts: 490 Karma: 1641 Join Date: Oct 2006 Location: Louisville Device: Sony Reader PRS-500	wnapier, do you read your books from the SD card, or from the internal memory? That interesting thread RWood posted above clearly shows it uses at least 30% more power reading a book from a card.

03-07-2007, 10:25 AM	#28
HarryT eBook Enthusiast Posts: 85,544 Karma: 93383043 Join Date: Nov 2006 Location: UK Device: Kindle Oasis 2, iPad Pro 10.5", iPhone 6	As Mr Gnome so cogently observes, there's honestly no need to use a memory card unless you're viewing graphical PDFs or something; you can store 100+ books in internal memory which should be more than adequate for even the longest of reading sessions!

03-07-2007, 11:28 AM	#29
UncleDuke books & doughnuts Posts: 882 Karma: 37857 Join Date: Jan 2007 Location: usa Device: sony reader, kindle2	I charge every 3 books. Ran dry only once.

03-07-2007, 11:34 AM	#30
Frogsmasha Connoisseur Posts: 88 Karma: 10 Join Date: Aug 2006	I drained the battery out completly, and now I took all of my content located on my 1 gig SD card and transferred it over to the onboard 64 mb memory. I also did the soft reset once it was charged to 100% I took note of where I left off on my book, and I'll let you guys know how it goes in a week or two

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