After several times of my MBP shutting down without warning, and while the battery indicates a charge of 83-85%, I did some checking. Here is what the computer says: Battery Information: Model Information: Serial Number: Sony-ASMB012-3734-9d57 Manufacturer: Sony Device name: ASMB012 Pack Lot Code: 0003 PCB Lot Code: 0000 Firmware Version: 102a Hardware Revision: 0500 Cell Revision: 0303 Charge Information: Charge remaining (mAh): 3966 Fully charged: No Charging: Yes Full charge capacity (mAh): 4699 Health Information: Cycle count: 63 Condition: Good Battery Installed: Yes Amperage (mA): 1501 Voltage (mV): 12421 Coconut confirms these figures. I tested it this way: when the battery indicator reads 99%, the mag safe light turns green. The battery icon says fully charged. I unplug the mag safe, and continue surfing. After about twenty minutes the computer shuts off - NO warning. Just before it dies, the battery meter says 83-85% charge remaining. So basically, I can only use about 15% of the battery's capacity. My usage is mixed - I'll have it plugged in for several hours a day, but also use it un-plugged to 'exercise' the battery. I've tried to calibrate it but when it shuts off at an indicated 83-85%, its hard to 'drain' the battery. Any suggestions before I try to get this battery replaced? TIA!