iPod 3rd Gen' - Battery Issue, Even after upgraded battery installed

[lawlcake]

Hey guys, I'm a slightly-long time lurker, first time poster, so go easy on me. I apologize if this is in the wrong section.

Anyways, I recently acquired the all-mighty iPod Classic 3rd generation. I previously had a sansa e280 with Rockbox on it and I thought it was about time to hang up the poor guy.

So, after upgrading the battery to a 850 mAh capacity battery, I install the Rockbox firmware I am oh so familiar with. However, I noticed that, even when iPod is off, it seems that the battery, for some odd reason, still is running. For example, Lets say I turn off the ipod at around 96 percent of battery full. I turn it on, it'll be around 80 percent, or even 75 percent. What's the dealio?!

Could this be a Rockbox problem, or a hardware problem? I doubt its a hardware problem, what with the new battery and all. Please help, and much thanks!

[AlexP]

If you are a long time lurker, I'm sure you have seen many messages like:

This is nothing to do with installation, so why have you posted it in the installation section?  Please read the stickies in each forum before posting.

There is no Classic 3rd Gen.  There is an iPod 3rd Gen, which I guess is what you have (Apple are hugely inconsistent in their naming, I'll give you that).

As for your problem, I seem to remember something like this coming up before a while ago - have a search and see what you find.  Also, a new battery doesn't rule out any hardware issues - it could be a bad battery (no-name ones from ebay are notoriously unreliable) or it could be some other hardware issue causing the battery to drain, even if they battery is fine.  This might have more chance of being true given how old the 3rd Gen players are now.

It could of course be Rockbox too I guess - the iPod 3rd Gen port is not the most used so something could always have slipped through.

[lawlcake]

For the record, I said "slightly-long time lurker", mainly because, as said earlier, I had a Sansa e280 with Rockbox on it, so I would just spend my time around here and see what's going on. Eventually I lost interest and the rest is history. I'm also aware that there's no 'classic' ipod for the 3rd generation, but I just used it to describe the ipod, just so people don't get confused. Hope that clears things up. Anyways...

I did a little test with the battery. I found out that, for an hour and 25 minutes of non-stop music play, the battery life goes from 94 percent yo 78 percent, a gap of 16 percent. Once turning it off, then turning it back on after 10 minutes, I lost another 10 percent, bringing it to 68 percent.

My battery replacement was actually not done by me, but done by irepair.ca in Toronto. They pretty reliable, and I'm pretty sure that their batteries aren't from ebay.

in terms of hardware, what component do you think could be causing this? Any idea?

[Llorean]

Have you tried seeing if the battery capacity is really that much lower. Some players report a lower capacity on boot, but after a period it either levels out or turns out not to affect the actual runtime.

[lawlcake]

Actually Liorean, it does seem to be doing that. Is that some kind of bug or something?

[Llorean]

It's simply a hardware issue. Readings are made as accurately as what the hardware will tell us. It may be that the Apple firmware uses an old reading after sleeping until the battery has time to settle, or has some other cleverness we don't know about, or it may be there's still room for improvement in our code.

[dreamlayers]

In powermgmt-ipod-pcf.c, percent_to_volt_discharge only has values for Nano, Video and Color iPods.  Then there's this:
/* FIXME: calibrate value for other 3G+ ipods */
/* Table is "inherited" from iriver H100. */

Edit: Also, initial battery readings after power on can be low due to all the hard drive activity at power on.  They increase after a few minutes.  I even see this with the 5G Apple firmware after a fresh boot.

[lawlcake]

So, dreamlayers, what you're saying is the amount of volts that is being used in the iPod 3rd Gen is more suited to the more recent iPods (IE, video, nano, etc), and therefore, are using more power than it should. Correct or incorrect?

If that's the case, then how can this be fixed?

[dreamlayers]

So, dreamlayers, what you're saying is the amount of volts that is being used in the iPod 3rd Gen is more suited to the more recent iPods (IE, video, nano, etc), and therefore, are using more power than it should. Correct or incorrect?

If that's the case, then how can this be fixed?

No.  Sorry, I guess I was being a bit too technical.

The thing being measured is battery voltage.  It's impossible to directly measure percentage of charge.  Rockbox uses a table to translate voltage to percent of charge.  Right now Rockbox does not have a table for the 3rd gen iPod, and it uses a table from another device.  This causes the reported percentage to be less accurate.

This has no effect on power consumption.

You can help by performing a battery bench and posting the results.  For instructions, see http://www.rockbox.org/twiki/bin/view/Main/BatteryRuntime
Ideally, someone with an original battery should do the test, but I guess all original 3G iPod batteries have worn out by now.  This test will also allow you to see how well your battery performs. 

[lawlcake]

Now here's something interesting that happened to my iPod. After playing some music for, lets say, about 30 - 40 minutes, my iPod got VERY hot. It seems that the hard drive just kept on... doing things while I was listening to music, thus decreasing my battery life. However, once I switched to the iPod firmware, there was decreased activity in the hard drive, and therefore, more battery was conserved. Just something slightly interesting to note...

This weekend, I'm definitely gonna do that battery bench testing, and see what the heck is going on with my iPod. I'll post the results here, of course. Thanks to everyone for their help!

[dreamlayers]

Don't do the test if your iPod gets "VERY hot" or if the hard drive is constantly active.  This means something is wrong.  The data won't be useful, and it might be bad for your iPod. 

Rockbox should turn off the hard drive if there is no user activity and the hard drive is not being used.  There is a configurable timeout at Settings -> General Settings -> System -> Disk Spindown but the maximum is 254 seconds.

Which version are you using?  If not the latest, try the current build:  http://build.rockbox.org/dist/build-ipod3g/rockbox.zip

[lawlcake]

Sorry about the long-time no response, I've been busy.

Well, I was using a previous daily build, but I think updating it did the trick, it's not becoming hot anymore. However, the battery life is still significantly lower in Rockbox than using the regular iPod firmware. I haven't done any bench-pressing for both of the firmwares yet, but, I should be able to very soon.

In the mean time, are there any other strategies to conserve battery life other than reducing the backlight timeout?

Sorry about all the help guys, but you guys have been very friendly and helpful so far, it's very much appreciated!