Battery only charges to 75%

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Level 1

5 points

Battery only charges to 75%

I've read over the forums, but I don't think I've seen an answer for this one.

I have a G3 500 Mhz iBook with the 45W power adapter.

I've done the power down, take out the battery, press reset, wait 5 seconds, power up, and put the battery back in thing.

I've done the turn off, hold option-command-p-r thing.

I've let the battery completely discharge and charge back up to 75% twice now, but it never goes up to 100%.

The battery has 3 lights on the bottom, and the power adapter never goes to green.

When I first got the computer it worked fine. As far as I can tell, the only thing I've done is apply the system updates including the battery update. Could it be the battery update that's causing my problem, and is there any way to uninstall it?

Posted on Nov 11, 2005 9:17 AM

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Answer 1

AshmanE Author

Level 1

5 points

Nov 11, 2005 10:12 AM in response to AshmanE

Interestingly enough, when I take the battery out of the iBook and press the button it then registers a full charge with all 4 lights lit.

But the iBook never showes it going above 75% or 76%...

Now I don't know which reading to believe...

This is getting more confusing the more I mess with it. I guess I could always take it into the apple store and see if they can troubleshoot it for me...

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Answer 2

Nov 15, 2005 3:23 PM in response to AshmanE

How old is your battery? The average lifespan of a lithium-ion battery is two to three years. If your battery is approaching that age (or is past it), it may just be showing its age.

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Answer 3

Nov 15, 2005 4:15 PM in response to AshmanE

There was a very informative web page floating around out there about Li-ion batteries and how their charge/discharge cycles over time develop anomalies because their internal chemistry is aging. A typical battery is in fact several individual cells connected serially. If one cell is damaged, aged, or otherwise weakened, it shows up as a sudden drop in voltage and the computer sleeps without warning. Conversely, when the battery is charged, the weakened cell doesn't accept any more charge and the battery never fully charges, in the sense that the percentage is reported incorrectly, but the battery is in fact at its maximum charged capacity.

The short answer to your question is that your battery is probably at the end of its useful life span. Unless it is less than a year old, this behavior can be expected, especially if the battery has been exposed to high temperatures or has been left in a completely discharged state for long periods of time.

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