Ipod turns suddenly off

[BlueBarry]

hello
i got a 5.5G (30g Video) Ipod and a problem with RockBox.
my ipod automatically shut down after 15 minutes of hearing music
and trying some options...
the battery is full... i don't know why this happens.

i need some help please

[Chronon]

Was one of the options the sleep timer?

[BlueBarry]

no I just tried the equalizer.

my ipod says it got low battery wehn it turn off and if i wait like 2 minutes and start my ipod again the battery is shown as full but...again 15 minute and it shut off.

[Ahz the Cat]

I have a very similar problem with my own 5g 30gb video ipod.  I have fairly decent battery performance in the original Apple OS...I`ve been listening to it for the last two hours with no problems...but when I boot up Rockbox I get as little as 2 minutes of playtime or as much as 40 minutes before the iPod just shuts down.  No warning, no nothing, just a click and a black screen. 

If I wait about ten minutes or so after one of these events the battery recovers enough to allow me to reboot, but if I fire up rockbox again, I get scant seconds of juice.   I thought it might be the wrong build for my iPod, so I double checked, pulled down v3.1 and reinstalled, but nothing changed. 

I also installed ipodLinux, just to see how that performed, and had the same battery issues.  From what I`ve been able to glean from the forums, my best guess is a battery starting to go out...but there also seems to be a general insistence that RockBox is just as gentle as AppleOS in terms of battery management.  From my experience, this must not be quite the case. 

Perhaps overall performance is more or less equal between ApOS and RockBox, but there must be a difference is peak loads or something ...   

All this being said, I`ve run RockBox on my 3g iPod for years now, and love it.  I think the software is brilliant, and really look forward to getting this 5G sorted out. 

Thoughts?

[Febs]

no I just tried the equalizer.

my ipod says it got low battery wehn it turn off and if i wait like 2 minutes and start my ipod again the battery is shown as full but...again 15 minute and it shut off.

The equalizer is processor-intensive, and therefore puts a relatively high load on the battery.  My guess is that your suspicion is correct and your battery is starting to show signs that it needs to be replaced.

Note that while the equalizer is software-based, the "bass" and "treble" controls are hardware-based and use substantially less power.  If you don't need to full flexibility of the equalizer, try those controls instead.

Thoughts?

I suspect your problem is also that your battery needs to be replaced.  If you try a battery test with the original firmware, I think that it is likely that you will find that you get a significantly shorter runtime than the time estimated by Apple.

[Ahz the Cat]

I`ve already ordered a new battery, so we will see if that helps.  I really don`t want to swap back to the ol 3G.

I am interested in this battery usage profile question...is it just that Apple os just doesn`t hit as hard when it draws on the battery?  I`m gonna fiddle around a bit more and see if I can get rockbox going even on this lame battery.  I am sure iPodLinux is gonna be a nonstarter util the power situation is cleared up....

[Chronon]

BlueBarry: I agree with Febs.  Old batteries degrade in their charge capacity.  When a battery can no longer supply the necessary current it no longer acts as a voltage source.  Once the current draw depletes what the battery can produce, the voltage will rapidly drop and this will tend to flag a shutdown condition to save the battery from deep discharge.  Once the load is removed (due to shut down) the voltage between the battery terminals will return to a higher level.  This is the best explanation for what you're seeing at the moment that I can come up with.

Ahz the Cat: Probably the difference that you're seeing comes down to different decision making about when to engage safeguards to protect the battery.  If you discharge a Li+ battery too deeply it will be permanently ruined, so there's generally some failsafe that forces a device to shut down before this condition is reached.  Probably, Rockbox is a bit more paranoid than the Apple firmware.  For a healthy battery there is not much difference in runtime between Rockbox and the Apple firmware -- I believe it's even a bit more for earlier generation iPods.

[Ahz the Cat]

So if RockBox senses a dangerously low battery condition it will just shut down with no warning?  Thats good to know. 

I`m not sure thats exactly what`s happening though...seems like a momentary high load condition is the cause of the shutdown, and the battery needs time to recover afterwards.   Old batteries are much less resilient than new ones, I`m assuming.

In fact, I was listening to the 5g in rockbox as I was typing this...I got 4 songs, a theme change, and a quick perusal of the database in before the thing just went dead.   This is after leaving in plugged in to the wall charger for 36 of the last 48 hours and the last 20 hours continuously. 

On my b&w 3g pod, I get better battery performance from Rockbox than with the original OS, with no funny hiccups.  Perhaps its simply that the 5g is greedier for juice regardless of firmware.

--Edit--
I was able to force the 5g to fail within the original firmware also...basically replicating the issue.  Playing a game and listening to music at the same time caused a shutdown in about 3 minutes.  Multitasking is apparently my culprit, that and a sick battery.   
--edit--
BlueBarry, if you are still having problems, try running two tasks (I played Parachutes and listened to mp3s) at the same time in your iPod`s native firmware.  If you get a rapid battery degradation similar to what you get with Rockbox, you can safely assume your battery needs replacing too. 

[Chronon]

Usually, a splash screen should be displayed when a low battery condition is detected.  It's possible that instant shutdown occurs if the voltage is too low, however.  Someone with more knowledge of the source code will have to address that point.

The voltage between the battery terminals can drop very quickly if the battery cannot source enough current.  Once the circuit is opened the voltage will creep back up since current is no longer being depleted. 

Yes, aging degrades the charge capacity of Li+ batteries.

[Ahz the Cat]

Well, the battery I ordered came, I slapped it in, and lo and behold, my power issues are over.
Rockbox runs great for hours on end, and I can fiddle with it all I like and no sudden shutdowns.  Occam`s Razor has once again been proven right!  

Thanks for all the feedback folks...Cheers!

[Chronon]

That's good to hear!