This battery is Compatible With Lenovo s850 s850t ..Battery is dead in starting, kindly charge immediately after getting delivery. The maximum back up of the battery depends on the minimum use of the internet and video playing. This battery from the house of GNG is made. It has been designed specifically for your Smartphone and is ideal as a second battery or replacement for your original battery. Simply charge one while the other is in use and you'll be able to use your smartphone all day every day. Do not overcharge the battery for the whole night.