Computer shuts down when unplugged

Question

I have a late 2006 MacBook Pro. Got a replacement battery a month or so ago. Everything was going fine until all of a sudden yesterday - if the power cord comes unplugged, the computer immediately shuts down. The cord shows a green light, the battery shows green lights when the button is pushed. The icon in the top right says "calculating" and shows 77% (hasn't changed since the issue began yesterday). The battery was operating fine - had about 2 hours or so of charge - so it's not that it's been on the way out or anything. Checked the "about this mac". This is the readout:
System Power Settings:
AC Power:
System Sleep Timer (Minutes): 10
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: Yes
Display Sleep Uses Dim: Yes
Battery Power:
System Sleep Timer (Minutes): 5
Disk Sleep Timer (Minutes): 10
Display Sleep Timer (Minutes): 5
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): 5425
Remaining Capacity (mAh): 4193
Amperage (mA): 0
Voltage (mV): 11949
Cycle Count: 35
AC Charger Information:
Connected: Yes
Charging: No
Hardware Configuration:
UPS Installed: No
Any ideas?

Answer 1

Is this an Apple-branded battery and was it sold as "new?" I ask because amassing 35 cycles in a month is hard to do.
We're seeing more reports of people getting MBP batteries from a auction site or web reseller that are not Apple products and give poor performance. They are commonly advertised as "new: but arrive with a lot of cycles on them.
Your remaining full charge capacity is under 80 percent whether you have a 15- or 17-inch MBP (the battery baselines for calculating the percentage are different). Apple says you should have 80 percent after 300 cycles. Their batteries seldon do that many byut generally more than 35.
The battery is basically defective. I doubt any action on your part can fix that other that returning it to the vendor ASAP.