Power Consumption and Battery Life
Lenovo rates the 6-cell battery that accompanied our T400s test rig for up to 5.5 hours of life. You can imagine Lenovo is going to go with the best case scenario for this battery rating, however. In our real world tests, we found the battery life to be around two hours and nine minutes using BatteryEater Pro’s Classic test.
Although we have to think that 5.5 hours is a bit of a stretch, it’s feasible that you would be able to get additional life out of the battery, provided you’re not working the machine 100% of the time with a heavy workload like we were during the battery test.
As you can see, there are other notebooks out there that beat the T400s in terms of battery life, but most of them are in different classes and are not as small or as lightweight. For users who require additional power between charges, Lenovo also offers a 3 cell Ultra Bay battery that provides up to an additional 3 hours of battery life when combined with the 6 cell battery, according to Lenovo.