I charged my PRS-500 today using a lab power supply.
The battery was empty (reader came up, said "LOW BATTERY", then "NO BATTERY", then shut off immediately).
After I found out that USB charging won't work without driver,
I used plan B: a power plug from a universal adapter set and a lab power supply. I set it to 5.20V, turned output on and the reader started charging right away at about 560mA. Now, about 2 hours later, current is down to 140mA.
I then switched the reader on, it showed the "starting up..." screen.
During startup it consumed about 140mA more than when it was off (and only charging).
As long as the unit is just sitting there and no buttons get pressed, there is little or no additional current consumption (less than 5mA, maybe zero; the accuracy of the ampmeter in the lab power supply does not allow for more precise measurements, sorry).
A page turn causes a short (<2s) increase in current consumption, with a peak of about 220mA.

So much for the raw data.

Now a few ballpark figure calculations just for fun:
Lets assume a page turn consumes 180mA for 2 seconds. This means 360mAs or 0.1mAh per page turn. Judging from the physical battery cell size, it has a capacity somewhere in the 800mAh range. At 0.1mAh per page turn, you would get 8000 page turns out of a full charge in a perfect world. Well, pretty close to the 7500 claimed by Sony, considering that these are just ballpark figures.. :)

^_^

VERY interesting work!

It would be cool if you could test power consumption with books stored in internal memory vs. books stored in external memory such as an SD card. We have numerous reports that the latter uses considerably more power per page turn.

It would be cool if you could test power consumption with books stored in internal memory vs. books stored in external memory such as an SD card. We have numerous reports that the latter uses considerably more power per page turn.

The measurements were taken with books in internal memory, no memory card inserted.
Hmm, unfortunately, I don't have a SD card or MemoryStick here now. I'll be able to test it next week thursday or friday.
From what I know about the usual current consumption of SD cards, I estimate a memory card would raise the page turn current by about 40-60mA.

Some more info: When charging was complete, current consumption from the lab power supply with a book page on the display was shown as zero (lab ps ampmeter, not sure if it was really zero, lets say: below 1mA). Page turn current peaked at about 220mA (drawn from external power supply, no mem card).
Varying the external supply voltage from 4.8V...5.2V didn't make a difference in current consumption.

^_^

Very nice analysis, rothe957, very nice, indeed. :yes:

Some more info: When charging was complete, current consumption from the lab power supply with a book page on the display was shown as zero (lab ps ampmeter, not sure if it was really zero, lets say: below 1mA). Page turn current peaked at about 220mA (drawn from external power supply, no mem card).
I guess page turn also varies depending on the complexity of the content.

Nice work, rothe!

This is a cool experiment, especially to give real-world numbers to corporate marketing claims. I too, would be interested in the power consumption using and SD card; hopefully you can find locally for ~$10 or so to test it out (could always pull one out of your digital camera or old-school MP3 player ;-) )

Thanks for informing us, 8k pages is friggin cool!

You can charge it from USB without the driver. Just use linux and libprs500.

You can charge it from USB without the driver. Just use linux and libprs500.

:) Well, I admit that I consider installing the driver the easier way.
Compared to installing Linux and then getting and installing libprs500.
I have a few linux machines in my office/workshop, but these are all embedded non-x86 devices without USB.
:) No, as tempting as it sounds - I think I stick to the lab power supply, and try to remember to bring the Sony driver CD next time.

^_^

Well, I added a current sense resistor (1 Ohm) to the setup, and connected a scope.
X axis is time, 1 second per grid. Y axis is current, 100mA per grid.
The small "1->" marks the zero current line.
Screenshots were done the lotech way, with a camera.

First some measurements with files in internal memory:

Turning the reader on then off again, Baen RTF file, internal memory:
http://www.sigma957.org/bilder/eReader/OnOff_RTF_int.jpg

Page turn, Baen RTF file, internal memory:
http://www.sigma957.org/bilder/eReader/Page_RTF_int.jpg

Page turn, PDF file ('1984'), internal memory:
http://www.sigma957.org/bilder/eReader/Page_PDF_int.jpg


Next with files on SDcard (Sandisk 1GB):

Page turn, Baen RTF file, SDcard:
http://www.sigma957.org/bilder/eReader/Page_RTF_SD.jpg

Another page turn, Baen RTF file, SDcard:
http://www.sigma957.org/bilder/eReader/Page_RTF_SD_2.jpg

Page turn, PDF file (Atmel datasheet, with graphics), SDcard:
http://www.sigma957.org/bilder/eReader/Page_PDF_SD.jpg


And another test set with a Sony MSmicro (512MB) with MS adapter:

Page turn, Baen RTF file, MSmicro:
http://www.sigma957.org/bilder/eReader/Page_RTF_MSmicro.jpg

Another page turn, Baen RTF file, MSmicro:
http://www.sigma957.org/bilder/eReader/Page_RTF_MSmicro_2.jpg

yet another page turn, Baen RTF file, MSmicro:
http://www.sigma957.org/bilder/eReader/Page_RTF_MSmicro_3.jpg

Page turn, PDF file (Atmel datasheet, with graphics), MSmicro:
http://www.sigma957.org/bilder/eReader/Page_PDF_MSmicro.jpg

RTF formatting + update of wait symbol, Baen RTF file, MSmicro:
http://www.sigma957.org/bilder/eReader/Format_RTF_Updatewaitsymbol_MSmicro.jpg

Conclusions, anyone?

^_^

The big spike followed by high consumption and noise is what I would expect from the eInk circuitry. This probably has a high-voltage DC-to-DC converter, followed by a matrix of drivers for row and column lines in the display.

This shows a big spike of current draw as it starts up and charges all its capacitors. Then the variable load producing the noise is a combination of this supply and the variable capacitive load as different lines in the eInk display are charged and discharged, Obviously this is a big user of power.

There seem to be 3 load levels. One is fairly low, probably the CPU coming out of sleep mode. The second appears to correspond to display preparation, as it's much longer for the PDF file display. Not sure if this is CPU use, display buffer being powered up, or flash memory access. The highest level seems to be when the eInk power supply is being used.

When used with external flash, the second level of current draw takes longer before the page display, so this second level probably does indicate internal or external flash memory access. (External flash access also appears to be much slower). Also, the CPU stays active for several seconds longer after a page update. So using external flash memory will shorten battery life by up to 40%, I would expect. Of cource, it looks like viewing complex PDF files is even more expensive.

So it's generally true to say that RTF is better than PDF in terms of battery life?

Hmm, wonder about the the BBeB format; especially for say a PDF that was converted using tools fromt this website? I'll post something you can test with here after it finishes transcoding. Didn't have any small PDF's already converted that I could u/l so you could test actual PDF vs. (hopefully) improved LRF. That is, of course, if you don't mind running the test with the samples I've provided.

Note: It's a freely available eZine converted from the distributed PDF to LRF using PDFRasterfarian v2.1.4.

Edit: Here are the files, thanks for posting your data!

That is, of course, if you don't mind running the test with the samples I've provided.

I'll see what i can do. It might be a while until I have access to the scope again, though. Please be patient.

So it's generally true to say that RTF is better than PDF in terms of battery life?

I think it depends more on complexity. RTF is formatted text only. Formatted text in a PDF (see '1984' example) doesn't seem much different in terms of rendering time. A complex PDF with graphics etc. takes longer to render and thus needs more power per page turn.


^_^

This shows a big spike of current draw as it starts up and charges all its capacitors. Then the variable load producing the noise is a combination of this supply and the variable capacitive load as different lines in the eInk display are charged and discharged, Obviously this is a big user of power.

I agree on all points but one: that spike is the inductor in the eink DC-DC convertor being charged.

I agree on all points but one: that spike is the inductor in the eink DC-DC convertor being charged.

I guess it depends on the power supply design. When I'm designing circuitry like this, I tend to go overboard on capacitors for the output of the power supply to reduce EMI and improve requlation, so it can take a LOT of current at startup to charge these. On the other hand, most DC-DC boost converters for applications like this where size and weight are an issue would use very high frequencies (>500 KHz) and extremely small inductors, so these might not store much energy.

Anyway, I presume Sony took some care to get high efficiency from the converter, so most of the load can be assumed to be unavoidable given the voltage requirements and capacitance of the eInk display. Hopefully the evolution of these displays will reduce the voltage and increase the contrast as well.

It also looks like the display uses less than 40% of the total for most updates, so this may already be at the point of diminishing returns, Less time spend running the CPU and reading the flash would seem more likel;y to pay dividends.

It's easy to conclude that the SD card consumes more power per page turn than sony MS. Not much, but it might add up to some pages in the end. That and the difference between internal and external MS format might be slightly significant.

Great work!

Another area of power consumption that has gotten some posting space here is that of mp3 files. Unlike books, they consume power as long as they are playing. Could you run some tests with them from both the internal memory and from the same SD card that you used before. Also could you check both the startup power consumption and the power consumption over a period of time. This may give us some indication of the playback length available on the battery.

Hi: I am trying to find an external battery that would provide power for about 15 to 20 hours of music. Another poster has suggested the Universal 9800 mAh external battery found at www.dealextreme.com which can connect in via the UBS jack. I have queried the supplier as to suitabity but have not yet heard back. Do you have any suggestions? As I write this I am on (long) hold with Sony tech support. Thus far, none of their support folks have a clue. Ed

Why don't you just use a cheap MP3 player? Any of these should easily give you 20h+ music playback. The Reader makes a pretty lousy MP3 player, and it's dangerous too - all too easy to inadvertantly leave it playing and drain the battery flat.

Hi: I am trying to find an external battery that would provide power for about 15 to 20 hours of music. Another poster has suggested the Universal 9800 mAh external battery found at www.dealextreme.com which can connect in via the UBS jack. I have queried the supplier as to suitabity but have not yet heard back. Do you have any suggestions? As I write this I am on (long) hold with Sony tech support. Thus far, none of their support folks have a clue. EdI don't see a 9800 mAh unit there, but I do see an 8800 mAh unit for ~$75 that's about as big as an iPod Classic, and a ~$14 12000 mAh one that's almost as big as an iPod Classic.

I got one of these (http://www.sandisk.com/Products/ProductInfo.aspx?ID=2291) on sale at Best Buy for ~$40 -- it's the size of a pack of gum and runs for ~16 hours on a charge, plus it has a full GB of memory to the 505's 120 MB, and takes Micro SD Cards if you want more. And it does Audible.com books (which was my aim in getting it).

I offer that as one example of another way to listen to audio that makes better sense to me than using my Reader. :shrug:

The link to the 9800mAh battery is http://www.dealextreme.com/details.dx/sku.3303

i am curious how much power is being saved when ereader is turned off completely, as compared to stand by

since we know to boot it back up takes power, so if don't use it for N days, it's better to turn off and reboot than let it standby, i wonder what N is :P

ns66 that is a really good question. I would love the answer.

You can charge it from USB without the driver. Just use linux and libprs500.

is there any special usb charger for Europe? (for the 500 - got mine yeasterday)

So far as I've ever heard, the only way to USB charge a 500 is with via a computer with the Sony Software or libprs500 installed on it.

You can wall-charge it with a Sony PSP charger, however. :beam:

Yes, I know about the sony psp charger, but there are quite a few of them (different types to me - not very clever about these toys) and since I am in the Czech Republic, I would not want to destroy my reader (got it yeasterday) by choosing the wrong one.. any pics out here?

I found this in my local e-store: http://www.speed-link.cz/sony-psp/movie--music-stands/-/sony-psp-desktop-charger-stand/1182.html

You need one with a round connector output, not USB.
I think this one should work:
http://www.speed-link.cz/sony-psp/kabely-a-adaptery/-/sony-psp-ac-dc-adapter/5547.html

You need one with a round connector output, not USB.
I think this one should work:
http://www.speed-link.cz/sony-psp/kabely-a-adaptery/-/sony-psp-ac-dc-adapter/5547.html

Thanks a lot :thumbsup: , I will check it out in their store. Blanka