Quick battery depletion, surprise shut down, and more

Question

Power info:
System Power Settings:
AC Power:
System Sleep Timer (Minutes): 0
Disk Sleep Timer (Minutes): 10
Display Sleep Timer (Minutes): 20
Automatic Restart On Power Loss: No
Wake On AC Change: No
Wake On Clamshell Open: Yes
Wake On LAN: Yes
Display Sleep Uses Dim: Yes
Battery Power:
System Sleep Timer (Minutes): 5
Disk Sleep Timer (Minutes): 10
Display Sleep Timer (Minutes): 1
Wake On AC Change: No
Wake On Clamshell Open: Yes
Display Sleep Uses Dim: Yes
Reduce Brightness: Yes
Battery Information:
Battery Installed: Yes
First low level warning: No
Full Charge Capacity (mAh): 1957
Remaining Capacity (mAh): 1957
Amperage (mA): 134
Voltage (mV): 12586
Cycle Count: 335
AC Charger Information:
Connected: Yes
Charging: No
Now, based on this and the age of my machine (2-3 years old), I would say that I am probably at the end of my cycle count for the life of the battery, right?
I have read other posts about similar issues (battery at 100%, then very quickly down to 60-80%, then poof - shutdown). I also read about someone who "worked around this" by putting the computer to sleep while plugged in, unplugging the machine, and letting it sit for about 4 days. Fully recharging, and things seemed pretty good. Based on the info above, think it is worth a try?
BUT WAIT - THERE'S MORE!
I have also been getting a buzzing/humming at start up, and sometimes while working. Took it to the Genius bar, they seemed to think it was one of the fans, so replaced that to the tune of $108. Sound eventually came back as battery performance became worse... related issue?

Answer 1

Your cycle count is over the limit. The remaining battery full charge/remaining capacity should reasonably be around 6000mAh. Get a new battery. zoz