Is this a genuine Xperia X battery?

[Miphee]

Hello, I just bought a battery for my F5121.

It doesn't look like a genuine battery at all but it has the Sony logo.

Is this a fake?

It loses charge way too quickly, almost 50% on idle overnight.

The last picture is an original battery, mine is entirely different.

https://imgur.com/a/otMy5QA

[CosmicTomato]

Well it looks okay, how about the packing?

No manufacturer sell their parts individually from the phones though, unless it's an old one that has been taken apart, so it mostly is a faker sadly.

[Miphee]

Well, couldn't really tell if it was genuine or fake so I sent it back. It lost a whopping 70% charge last night. It could be bad battery or bad phone. The only way to know is to check it with a smart charger to measure it's real capacity but the contacts are so small that it would be a real PITA. There are apps that measure battery life but they are wildly unreliable. So I decided to just get my money back instead.

When I asked Sony customer service about it they couldn't help me. First they lectured me about the importance of buying directly from Sony, and when I asked them to check if the serial number is valid they told me that they don't usually open the phones so they don't know about it. Completely believable that Sony doesn't have information on the batteries even if it's 3rd party. /s

Bottom line: it's almost impossible to tell if a battery is fake or genuine without capacity measurements.