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When running out of juice, powerbook does hard shutdown

Message #1 - Posted 2006/02/14 - wildatheart

Can anybody help me with this? Recently, my Alu G4 powerbook has started to do a hard shutdown (rather than a gentle sleep) when my battery goes to zero %. I do get the sleep warning at ten percent or so. It happens with two different batteries. I have done a PMU reset (remove battery, disconnect power and press power button 5 secs, right?).

Many thanks.

OS 10.4.4
1.5ghz G4 Powerbook

Message #2 - Posted 2006/02/15 - pailface88

wildatheart wrote:

Can anybody help me with this? Recently, my Alu G4 powerbook has started to do a hard shutdown (rather than a gentle sleep) when my battery goes to zero %. I do get the sleep warning at ten percent or so. It happens with two different batteries. I have done a PMU reset (remove battery, disconnect power and press power button 5 secs, right?).

Many thanks.

OS 10.4.4
1.5ghz G4 Powerbook

It is likely that his is happening because the battery is dying before the computer expected it to. The computer doesn't actually know how much power is left in the battery. When it registers that you have 10% left it does not know that. It is only assuming that. The way that it comes up with its assumption is that from past experience (last time you calibrated the battery) it learned at what voltage level how much of the batteries capacity reamined. But, over time the characteristics of your battery change. Your battery is not as spry as it used to be. Therefore your computer is making incorrect assumptions about its capacity.

The solution to the problem is to recalibrate your battery. To do this, charge it fully. Then discharge it by operating the computer until it shuts down. Then recharge it fully and the computer should now have a updated, correct measure on how much power is left at any given measured voltage level. It should not run empty unexpectedly.

Another possibilty is that your batteries are nearly worn out meaning its discharge curve may be much too irregular. If this is the case it may be impossible for the calibration process to produce usable data for the computer to work with.

Message #3 - Posted 2006/02/18 - wildatheart

That's fixed it; it's easy when you know how..! Many thanks.

Message #4 - Posted 2006/02/18 - John Johnson

Previously, wildatheart wrote:

That's fixed it; it's easy when you know how..! Many thanks.

Er, what fixed it? Having that information (e.g. by quoting the guy who gave you the fix) helps us to give correct advise to the next person with similar problems.

Later,
John

johajohn@indianahoosiers.edu

'indiana' is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.

Message #5 - Posted 2006/02/20 - wildatheart

Of course I should have quoted; my bad. Anyhow, this fixed the premature hard shutdown (as opposed to sleep) of my powerbook.

The solution to the problem is to recalibrate your battery. To do this, charge it fully. Then discharge it by operating the computer until it shuts down. Then recharge it fully and the computer should now have a updated, correct measure on how much power is left at any given measured voltage level. It should not run empty unexpectedly.

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