Question: If I remove the battery & run from a power source will it lengthen battery life?
Laptop batteries have finite life spans. Whether you use the power cord or remove the battery it will lengthen the life of the battery.
Li-Ion laptop battery lifespan is approximately 1,000 charge cycles, or 2-4 years under normal operating conditions.
Keeping the battery in a cool place can prolong its life but not in a period of extended storage. The Li-ion battery should be stored at 40 percent rather than full-charge state.
The battery ages even if not used. For best results, keep the battery cool. In addition, store the battery at a 40 percent charge level. Never fully charge or discharge the battery before storage. The 40 percent charge assures a stable condition even if self-discharge robs some of the battery's energy. Most battery manufacturers store Li-ion batteries at 15°C (59°F) and at 40 percent charge.
Keeping a laptop battery on constant charge and never using it is not good for the laptop battery. Run the battery down and recharge it at least once every month.
(From Catherine Roseberry, former About.com Guide - reprinted from About.com)