Your Lenovo laptop is your constant travel companion: it goes with you to school, work, the coffee shop and everywhere else. And when you can't find an outlet to plug the computer in, you trust your Lenovo battery to keep your laptop alive. Replacing you battery, or even just choosing a second one, requires knowing your computer. Lenovo offers different batteries for its various computer lines. IdeaPad computers like Lenovo G550 the use an 11.1-volt six-cell battery, while many ThinkPad laptops use a 10.8-volt, six- or nine-cell T500 battery. The larger battery does protrude behind the case, but offers a 7200 mAh capacity rather than the standard 5200 mAh?which means more time away from an outlet. It's easy to find the Lenovo battery you need from reliable sellers on eBay. All you need to do to change your battery is undo the latches and slide it out. Give your laptop the gift of life with a new battery.