I purchased an "genuine Lenovo" battery off Ebay for my Carbon X1 2nd gen. The battery matched the existing one with the exception that the wires to the connector were a higher gauge. After installing the battery and booting up, the laptop would not recognize the battery. I tried uninstalling the battery "drivers" to no avail. So I am left with two conclusions. The battery I received is defective, or it is a knock-off and Lenovo has a battery whitelist. Problem is that if it needs a real official Lenovo battery, they are near impossible to find (new ones) and the one that Lenovo sells is like $160, which is above what I am willing to spend on an old laptop. Can anyone confirm if there is a whitelist blocking batteries? Thanks!