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Author Topic: iPOD switch off based upon battery level  (Read 2060 times)

Offline Buschel

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iPOD switch off based upon battery level
« on: May 27, 2007, 04:47:18 AM »
Hello,

is the switching off of an iPOD done by rockbox based upon the battery level (voltage)?
Or will the unit simply stop to work some time (not triggered by rockbox)?
From what I saw in the source-code in powermanagement rockbox does only calculate the estimated runtime and battery-level (in percent) but does not perform any kind of shudown.

I ask as I see quite different runtimes (with battery test plugin) over several measurements. The main reason for the differences is that the iPOD switches off at different voltages (3,49V - 3,66V). In runtime this range equals 20-30min.
Does anybody know why shutdowns take place at different levels?
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iPod 5.5G 30GB, iPod nano 2G 8GB, 97% MPC and growing...
 

Offline Llorean

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Re: iPOD switch off based upon battery level
« Reply #1 on: May 27, 2007, 04:52:18 AM »
Battery Benches don't reliably tell you when the shutdown happened. This is because it takes power to spin up the disk, and thus write the battery log. Since the disk only spins up when the playback buffer needs refilled (and thus the log is only written when that happens) this can be 20-40 minutes per chunk written to the log, depending on the bitrate of buffered audio. This means that the last entry in the log only tells you within approximately 30 minutes when the disk was last able to spin up.
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Offline Buschel

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Re: iPOD switch off based upon battery level
« Reply #2 on: May 27, 2007, 06:12:51 AM »
Ok, differences in measurements are clarified.
The other question is still open: Does rockbox shut down the iPOD, if battery voltage is below some defined value? Or does rockbox not affect the shutdown and runs until the hardware quits...
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iPod 5.5G 30GB, iPod nano 2G 8GB, 97% MPC and growing...
 

Offline QwertyAccess

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Re: iPOD switch off based upon battery level
« Reply #3 on: May 27, 2007, 08:04:16 AM »
i dont know anything about rockbox's code but from my observation it seems like the software turns off the ipod based on voltage/battery %, i know when i used my ipod it would run till the hardware nearly quits, and i'd start to see the LCD flicker, the rockbox just runs solid and then suddenly goes off saying it ran out power.

Glad to see someone trying to get the firmware to be more efficient, it really eats up power. If we can get power to be as good as the original ipod's or even better,  then rockbox will be unanimously the most competitive thing we got to the ipod's limited firmware.
« Last Edit: May 27, 2007, 08:09:09 AM by QwertyAccess »
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Offline soap

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Re: iPOD switch off based upon battery level
« Reply #4 on: May 31, 2007, 09:06:47 PM »
Quote from: Llorean on May 27, 2007, 04:52:18 AM
Battery Benches don't reliably tell you when the shutdown happened. This is because it takes power to spin up the disk, and thus write the battery log.
For what it's worth, the iPod runtimes in the wiki done by me are based upon actual observed death, not the last reported time in the battery bench.
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