Macbook randomly shuts off while on battery power.

Question

I have a 13-inch Macbook, Late 2008 model, using iOS Mavericks. While on battery power, the laptop will randomly just turn completely off, despite still having plenty of battery power left. I know it's not a calibration issue where the battery is dead but appears to have charge left, since I'm able to turn the computer back on again and continue using it.
Battery info:
Charge Information:
  Charge Remaining (mAh): 606
  Fully Charged: No
  Charging: No
  Full Charge Capacity (mAh): 2609
  Health Information:
  Cycle Count: 157
  Condition: Service Battery
  Battery Installed: Yes
  Amperage (mA): -1265
  Voltage (mV): 10855
Message was edited by: airheadoh

Answer 1

First try the SMC reset appropriate for your model: Intel-based Macs: Resetting the System Management Controller (SMC)
The information you posted says "Condition: Service Battery" - that likely means you will need a new battery sooner, rather than later, especially if an SMC reset doesn't help the situation at all.
In any case, when new, your battery likely had about 4400 mAh (milliAmphours) Full Charge Capacity.
The Full Charge capacity is down to about 60% of original capacity 2600/4400
A direct replacement from Apple is $129, installed.
Any popular search engine will provide a list of less expensive suppliers, but I cannot recommend any, simply because I haven't used any non-Apple replacement batteries recently. My single experience with one lower-cost supplier for my polycarbonate 2007 MacBook (replaced in 2010) was that the cheaper battery needed to be replaced again within a year. Your mileage may vary.