Laptops have become widely used due to their power and portability. There is still a price premium when comparing feature for feature with an equivalent laptop, but it is offset by the convenience offered by laptops. All laptops and portable systems offer the ability to run on battery power. The run times vary widely from model to model. The battery technology has changed also over the years, going from Nickel Cadmium to Nickel Metal Hydride, to Lithium Ion. Each type of battery has different requirements in care, but there are things you can do to extend the length of time you can run on a single charge.