17" MBP quits on battery power & not on A/C

[Mr.Gadget]

I have an almost 3 year old MacBook Pro 17" 2.33GHz C2D.
When on battery power, I can run the laptop for about 20 minutes and then it just powers off, as if I pressed the power button and held it.
The level indicator on the battery itself shows 4 LEDs and the O/S, when plugged in and rebooted, shows, typically, around 73% to 75% battery power left.
The system can (and does) run for eight or nine hours on A/C (at work) with no problems. Can this still be a battery issue?
Also, I just added an Express Card e-SATA controller recently but it is not used at home or on battery, just at work. Is it just coincidence that these problems are happening together? When the e-SATA card is pulled, it no longer shows up as part of the system.
Is it possible to be a battery issue when it never really dies? Like, maybe it is lacking the correct voltage?
Thanks!

 

[175170]

I have an almost 3 year old MacBook Pro 17" 2.33GHz C2D.
When on battery power, I can run the laptop for about 20 minutes and then it just powers off, as if I pressed the power button and held it.
The level indicator on the battery itself shows 4 LEDs and the O/S, when plugged in and rebooted, shows, typically, around 73% to 75% battery power left.
The system can (and does) run for eight or nine hours on A/C (at work) with no problems. Can this still be a battery issue?
Also, I just added an Express Card e-SATA controller recently but it is not used at home or on battery, just at work. Is it just coincidence that these problems are happening together? When the e-SATA card is pulled, it no longer shows up as part of the system.
Is it possible to be a battery issue when it never really dies? Like, maybe it is lacking the correct voltage?
Thanks!

How many battery cycles?
I'm also guessing no AppleCare?

 

[t0mat0]

Might want to recheck your energy saving/ power settings. Could be that you've simply told the machine to turn off completely after 20 minutes rather than just dim screen/go to screensaver/turn off Hard drive/sleep ?

 

[Mr.Gadget]

I'll check the cycles on the battery and post the info. I do have Apple Care until September
I will also check the power settings when on battery, but, once the system shuts down, I can hit the power button again to boot up, but it will shut down after a few seconds at the initial gray boot screen, so I'm thinking it is not the power settings (but ya never know).

 

[veedubdrew]

It's a dead battery. I've had several over the years that behave exactly like this and a battery replacement made everything work properly again.

My understanding is that the voltage sags very quickly once the cells go TU, and the machine is incapable of running after a certain point on such low voltage and just shuts down. They don't (in my experience) fail in a linear fashion.

 

[Mr.Gadget]

It's a dead battery. I've had several over the years that behave exactly like this and a battery replacement made everything work properly again.

My understanding is that the voltage sags very quickly once the cells go TU, and the machine is incapable of running after a certain point on such low voltage and just shuts down. They don't (in my experience) fail in a linear fashion.

I'm going to give AppleCare a call this morning.
Here is my battery information from the "About This Mac". The battery is installed and the power adapter plugged in. Note how it says that it is not charging...

Battery Information:

Model Information:
Serial Number:
Manufacturer: SMP
Device name: ASMB014
Pack Lot Code: 0001
PCB Lot Code: 0000
Firmware Version: 0102
Hardware Revision: 0202
Cell Revision: 0100
Charge Information:
Charge remaining (mAh): 5009
Fully charged: No
Charging: No
Full charge capacity (mAh): 5099
Health Information:
Cycle count: 249
Condition: Good
Battery Installed: Yes
Amperage (mA): 276
Voltage (mV): 12572