ThinkPad Battery 83 (4 cell, 41W) (4X50M33574) The 4-cell ThinkPad battery 83 is a replacement/spare battery for ThinkPad new E-series system. The battery is rechargeable and can be used as replacement or as a convenient spare for ThinkPad E570, E570c & E575 systems. This battery is powered by Lithium-Ion technology and has a safeguard chip which authenticates with Lenovo systems. The battery lasts on average 41 watt hours and utilises over-discharge protection to ensure a secure flow of power. Many factors affect battery life. These include: screen brightness, battery conditioning, features, applications, power management and other customer preferences.Feature: Lithium-Ion (Li-Ion) technology4 cell bump battery Over-discharge protection to prolong the life of the battery Battery energy (Watt-hours): 41Wh Battery Safeguard chip authenticates with Lenovo systems