11-10-2008, 01:24 PM | #1 |
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Why the short battery life?
Why does the iLiad have such a short battery life, compared to other e-ink readers?
The iLiad Book Edition looks like a nice device, but it appears to top out at 15 hours on a full charge, which is not even long enough for a trans-Pacific flight. Why the HUGE difference in battery life from the likes of the 505, when it uses a similar screen (albeit a bit larger?) |
11-10-2008, 02:16 PM | #2 |
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Mostly it's due to the iLiad not having good power management features. iRex originally intended on having things like a suspend or hibernate mode in the iLiad, but it never happened. What they said is that it's impossible based on the hardware and OS combination that the iLiad is based off of.
Just a question, but do you plan on reading non-stop for the duration of the flight, or can you turn the iLiad off when you're not using it? That will make the battery last a lot longer. If you don't need to be reading continuously, then 15 hours of "on time" may be enough to get you through a flight. |
11-10-2008, 02:38 PM | #3 | |
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Quote:
Also, while traveling, or even at home, I don't want to be thinking constantly about plugging in my "book," lest it dies in the middle of the page. I just got the PRS-700 as my first ebook reader (and read for almost 5 hours in bed, with the battery indicator remaining at "full.") I am tempted by the larger screen of the iLiad, but the battery life is a show-stopper, for my needs:-( I am surprised, that there is no other ebook device with the 8" screen, and better battery life. |
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11-10-2008, 03:07 PM | #4 |
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Also, I see that there is active OS enhancement development. I'd have thought, that power management would be at, or near the top of the list.
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11-10-2008, 03:52 PM | #5 |
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There are battery upgrade steps posted on the boards that will get you somewhere around 35 hours of continuous runtime with larger batteries. Takes a few minutes of soldering and ordering replacement batteries for about $30.
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11-17-2008, 01:15 PM | #6 |
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Thanks, Mr. Goodbar. I am not sure I'd like to solder a brand new iLiad, though
Can someone tell me, how long does the iLiad last if not used? Does the battery discharge in a day even if not used for reading, or does it last a few days? |
11-17-2008, 03:43 PM | #7 |
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Once you turn it off there is no drain on the battery so it will last some time and is only impacted by the normal discharge cycles for li ion batteries.
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11-17-2008, 05:02 PM | #8 |
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Thanks, Mr. Goodbar. That did it..., I just ordered the Book Edition
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11-17-2008, 06:55 PM | #9 |
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This may be a really stupid question:
I just read, that after it loads a page, the iLiad still runs, albeit at 100MHz. I assume this is the reason for the significantly shorter battery-life, when compared to something like the Sony readers. I also assume, that if the processor can go to "sleep" once page is loaded, the battery-life can be extended significantly. If I am wright, then maybe someone really, really talented, can come up with a way to implement this, and make every iLiad user a happy clam. (I realize, that apparently iRex has stated, that they don't think it can be done, but from what I read, software is not one of their strong suites.... And I just don't want to give up hope:-) |
11-18-2008, 01:46 PM | #10 |
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From jharher's roadmap:
"... Milestone: 2.18 Due in 4 months (03/30/09) 0% Closed tickets: 0 Active tickets: 3 Power Management Using new kernel capabilities, some kind of sleep or hibernate functionality will be implemented if possible. In addition, the boot process will be streamlined in order to reduce boot time. Depending on circumstances, other possibilities include providing a very fast alternative, "minimalist" boot image. Also included in this release will be improvements in the battery driver to provide support for any sized battery...." I am so-o-o-o excited about this, it would make the iLiad by far the best device for my purposes. This has alleviated any doubts I had about ordering the device. I am keeping my fingers crossed that sleep functionality is possible - but does this apply to displaying a static page, which would extend the possible reading time, or to turning the screen off, which would extend the possible standby time? THANK YOU!!! |
11-18-2008, 02:14 PM | #11 | |
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Quote:
My advice would be to only buy an iLiad if it is already good enough, with any improvements in the nice to have but not essential category. |
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11-18-2008, 06:17 PM | #12 | ||
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It's not technically a sleep or suspend mode, but they do throttle the CPU some. Quote:
The iLiad is running a 2.4 linux kernel. The 2.4 kernel did not originally support sleep/hibernate at all. They didn't get full support for that until the 2.6 kernels came out. I believe, after 2.6 was released, the linux developers went and back ported some of the sleep/hibernate support into patches for the 2.4 series kernels. The existing kernel on the iLiad doesn't have that though, and I'm not sure if the particular processor that is in the iLiad will work with the back ported patches that were done for 2.4. You also can't just upgrade the iLiad to a 2.6 kernel because some of the proprietary drivers for hardware chips used in the iLiad are not available under 2.6. It's definitely not an easy problem to solve. |
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11-18-2008, 06:29 PM | #13 |
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Thanks, Shaggy. I did notice that the roadmap includes the 2.6 kernel, so I am crossing all my 20 digits that it actually happens. Because then all the battery-life limitations of the iLiad just go away, if I am understanding this correctly.
I am wondering if iRex is offering any help with the drivers required (they should, IMO.) Is there a kitty where one can contribute small donations for stuff like equipment, etc., for the volunteer developers? |
11-21-2008, 12:24 PM | #14 | |
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Quote:
It's a good thing to have it on the roadmap and spend some time looking into it, but I think it's going to be very difficult. |
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11-21-2008, 12:54 PM | #15 | |
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