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strange battery problem

Message #1 - Posted 2005/11/05 - velivolus

I have been experiencing this problem for awhile now and was wondering if there is a known glitch. What happens is that any time I am running my computer on the battery and using a CD, after about 10 minutes the screen goes black and there is no way to access my computer again save by plugging in the power adapter. Once I do this the desktop comes back and I can continue working. But the system believes the battery were completely drained and at 0%, and tells me it is going to take hours to recharge. Yet I had only been running the computer ten minutes or so on the battery! After recharging for awhile the system seems to realize its mistake and sets the battery back to 100%. This whole problem only seems to occur if I am using the computer's CD drive while running on the battery. I have never had this happen while running the computer without a CD inserted. I also remember once or twice, even when the computer was plugged in, going to use it, and there being a black screen and the computer was very hot. These were also times when a CD was in the drive, so I am thinking this may all somehow be related.

Message #2 - Posted 2005/11/05 - Tom Harrington

Previously, velivolus@gmail.com wrote:

I have been experiencing this problem for awhile now and was wondering if there is a known glitch. What happens is that any time I am running my computer on the battery and using a CD, after about 10 minutes the screen goes black and there is no way to access my computer again save by plugging in the power adapter. Once I do this the desktop comes back and I can continue working. But the system believes the battery were completely drained and at 0%, and tells me it is going to take hours to recharge. Yet I had only been running the computer ten minutes or so on the battery! After recharging for awhile the system seems to realize its mistake and sets the battery back to 100%. This whole problem only seems to occur if I am using the computer's CD drive while running on the battery. I have never had this happen while running the computer without a CD inserted. I also remember once or twice, even when the computer was plugged in, going to use it, and there being a black screen and the computer was very hot. These were also times when a CD was in the drive, so I am thinking this may all somehow be related.

It just sounds like your battery is old and worn out. When there's a CD in the computer you're drawing more power from the battery than when there isn't a CD, so that's probably the reason you notice this more then.

Tom "Tom" Harrington
Macaroni, Automated System Maintenance for Mac OS X.
Version 2.0: Delocalize, Repair Permissions, lots more.
See http://www.atomicbird.com/

Message #3 - Posted 2005/11/05 - velivolus

I considered this. The only thing is it happens very quickly after beginning to use an application on a CD. In other words, I can use the computer for 2 or 3 hours with no problem in battery mode. Put in a CD, and within two minutes the screen goes black. But likewise I can put in a CD right away and the same thing happens.

Message #4 - Posted 2005/11/07 - pailface88

velivo...@gmail.com wrote:

I considered this. The only thing is it happens very quickly after beginning to use an application on a CD. In other words, I can use the computer for 2 or 3 hours with no problem in battery mode. Put in a CD, and within two minutes the screen goes black. But likewise I can put in a CD right away and the same thing happens.

This can still be a worn out battery. Batteries fail in many different ways. They cannot put out as many amp/hours, not put the power out as quickly as in the past, individual cells can die before they all die, etc. If your battery is fairly old it is likely to be on its way out. They start to die the first time the are used...actually they start to die as soon as they are manufactured.

As an ecperiment, try running your CD on battery power but with the screen brightness turned completely OFF. The screen backlight is a significant power user and this may allow the CD to play longer. This is obviously not a solution to the problem but it may give some insight.

Message #5 - Posted 2005/11/29 - Juri Munkki

Previously velivolus@gmail.com writes:

I considered this. The only thing is it happens very quickly after beginning to use an application on a CD. In other words, I can use the computer for 2 or 3 hours with no problem in battery mode. Put in a CD, and within two minutes the screen goes black. But likewise I can put in a CD right away and the same thing happens.

Lithium Ion batteries corrode inside over time. This increases the internal resistance of the battery. Ohm's law states that U = R * I, where U is the voltage drop over a resistance R and current I. So when the current draw from the computer increases, the voltage drops because of the internal resistance. When the internal resistance is high enough, the voltage drop is significant and the computer thinks that the battery has been totally depleted and goes into emergency sleep.

The solution is to get a new battery. The catch is that you have to make sure that the battery hasn't been sitting on a shelf for a few years... I was lucky when I got a NewerTech 7.2Ah battery for my Pismo: I get a full day of power from that single battery (9 hours in one test case).

One more tip (and this is a big one): use the old battery whenever you have the computer plugged in at home or use the computer without a battery, if the old battery is too far gone. The reason for this is that the batteries corrode faster if they are hot and it's usually pretty hot inside an PowerBook that is doing anything.

I only keep that new PB battery in my Pismo when it's being charged or discharged. If it doesn't have to be in the Powerbook, it's sitting on a shelf, ready to go in the PB if I need to go somewhere. Lithium Ion batteries have a very low self-discharge rate, so it's almost as good as freshly charged even if it hasn't been in the Powerbook in weeks.

Juri Munkki - http://www.iki.fi/jmunkki - Windsurfing: Faster than the wind.

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