Battery discharges quickly

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Level 4

1,666 points

Battery discharges quickly

Hello! I searched but couldn't find a topic quite like my situation. I have an early 2008 MacBook (2.4GHz). The battery info is this:
Battery Information:

Model Information:
Manufacturer: DP
Device name: ASMB016
Pack Lot Code: 0002
PCB Lot Code: 0000
Firmware Version: 0110
Hardware Revision: 0500
Cell Revision: 0102
Charge Information:
Charge remaining (mAh): 0
Fully charged: No
Charging: Yes
Full charge capacity (mAh): 4778
Health Information:
Cycle count: 379
Condition: Normal
Battery Installed: Yes
Amperage (mA): 2064
Voltage (mV): 11056

System Power Settings:

AC Power:
System Sleep Timer (Minutes): 0
Disk Sleep Timer (Minutes): 10
Display Sleep Timer (Minutes): 5
Automatic Restart On Power Loss: No
Wake On AC Change: No
Wake On Clamshell Open: Yes
Wake On LAN: No
Current Power Source: Yes
Display Sleep Uses Dim: Yes
Battery Power:
System Sleep Timer (Minutes): 10
Disk Sleep Timer (Minutes): 10
Display Sleep Timer (Minutes): 2
Wake On AC Change: No
Wake On Clamshell Open: Yes
Display Sleep Uses Dim: Yes
Reduce Brightness: Yes

Hardware Configuration:

UPS Installed: No

AC Charger Information:

Connected: Yes
ID: 0x0100
Wattage (W): 60
Revision: 0x0000
Family: 0x00ba
Serial Number: 0x009168dc
Charging: Yes

CoconutBattery says 4778 mAh left from 5020mAh (95%), and 31 months old.

I understand from reading here that 379 cycles would be considered moderately high, but the 95% figure is encouraging to me.

The problem is this: From full charge, I get only 25-30% of the estimated time. It starts at 5+ hours remaining, and drops quickly. I noticed last night that I had ca. 1 hr. remaining, and I had to switch to charger within about 15 minutes.

I have recalibrated the battery multiple times, and reset the SMC multiple times. After this problem started, I began to monitor processor usage and it's typically between 80-95% idle. Only if I watch youtube videos or something does it get busier, but I expect that and I see this problem even when I don't do processor-intensive tasks.

I want to say when I first got this machine there would be times using it that the fan did not run at all. Lately it seems like it runs all the time, albeit slowly/quietly. I just installed smcFanControl to see the rpm and it's at +/-1800 rpm with the cpu ~90% idle and about 56ºC.

I also ran into the "battery indicator X" problem once back in the Spring, but I removed & reinstalled the battery and the problem has not recurred.

Have not contacted Apple yet but I do have AppleCare on the machine. Is it worth taking in? Any ideas as to what might be going on?

Thanks!

EDIT: It also discharges faster than I would expect whilst the machine is asleep.

Message was edited by: Declan MacLeod

MacBook 2.4GHz Core 2 Duo, Mac OS X (10.6.4)

Posted on Aug 27, 2010 3:38 PM

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Answer 1

Best reply

Scott Billings

Level 4

1,655 points

Aug 27, 2010 3:55 PM in response to Declan MacLeod

There's really nothing to do here, the battery is simply old and losing its ability to hold a charge. You can always check activity monitor to make sure you don't have a race condition (a process using large amounts of CPU time) somewhere, but if not, then expect things to get worse as time goes on until the battery doesn't hold a charge at all.

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Answer 2

Declan MacLeod Author

Level 4

1,666 points

Aug 27, 2010 4:10 PM in response to Scott Billings

Is this a typical failure mode? My understanding was that the discharge rate would remain more or less constant but the capacity would decrease with use and time. Mine seems to be the opposite -- capacity not much changed, but discharge rate increasing....

Cheers!

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Answer 3

Aug 27, 2010 5:56 PM in response to Declan MacLeod

It's a less common form of failure, but certainly not unheard of.

Modern batteries work by storing energy via chemicals. Some really strong acid to be specific. Every time you pass an electrical current through that acid, you change the chemistry a little bit. Over time, you change it enough that the energy storing properties no longer exist. Different batteries will be altered in different ways because of different circumstances. Yours fell into the broad group of quickly loses charge. If we were to carefully analyze your usage history of the battery, it would probably become clear why yours fell into the category it did... But it's really not worth that kind of effort. At almost 400 cycles, the thing is already on borrowed time, so consider yourself lucky it works at all.

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