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iPod not turning on (SOLVED)

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Llorean:
Just to clarify, if a Lithium based battery gets too low it can't really be recharged at all. The key point in bluebrother's post though is that "there's a line, and you can be below it instead of always starting from the line."

Think of your battery as being well below "0%" in Rockbox, and needing to get up *to* "0%" before you can start using it at all. A flat battery isn't always "0%", sometimes it's much less.

SindreD:
From Wikipedia:
"Li-ion batteries can even go into a state that is known as deep discharge. At this point, the battery may take a very long time to recharge. For example, a laptop battery that normally charges fully in 3 hours may take up to 42 hours to recharge. Or the deep discharge state may be so severe that the battery will never come back to life. Deep discharging only takes place when products with rechargeable batteries are left unused for extended periods of time (often 2 or more years) or when they are fully discharged so often that they can no longer hold a charge."

If I have understood bluebrother's explanation the right way, he means that the voltage will rise linear with a constant voltage/time=constant ratio, although this would contradict the function of electrochemical cells. I am not very familiar with the lithium-ion cells but from what I could understand from the explanation at wikipedia, the principle is the same as other electrochemical cells with two half-cells.

Then there is the possibility of deep discharging. Now, the circuit that charges and discharges the battery, will normally prevent the battery from getting deeply discharged, and will therefore prevent permanent damage. As quoted from the text above, this can only happen when the battery is left unused from extended periods of time, because of the circuit that drains small amount of power. I therefore have no reason to believe that my battery suffers from this.

Whenever I have used the ipod before, I have never encountered any behaviour similar to this. The ipod has just shut down, and immediately began communicating with the computer when charging. I still is a mystery to me why the ipod got into this state...

Chronon:
You should appreciate that the internal resistance of an electrochemical cell generally depends upon the charge state.  At low charge states the internal resistance will be much higher and this will dramatically reduce the effective amount of current available for charging at a given charger voltage.  This will lead to much longer charging times for lower states of charge. 

Just be patient and let your iPod charge.  It will eventually wake up and boot properly when the battery has enough charge.  I have had this happen on a few occasions with the two different iPods that I have owned.

Llorean:
Notably, we've seen reports of this with non-Rockbox iPods too. It's a common enough thing that happens to these devices, and we're not sure why.

SindreD:
I guess I'll just have to wait and see then. Thanks for explaining!

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