New battery decreasing capacity every charge

[pstt]

Hi.

I was bought brand new original battery from private seller to my 2010 macbook pro. I have a problem. My battery capacity is decreasing every charge. On first plug it was 100%, then 95, 88, 85 and now its 78% capacity..

I was perform reset SMC and calibrate battery, but nothing changes. My system is yosemite 10.10.4.

Is it normal or maybe battery is broken ?


Thanks in advance!

 

[pstt]

Updated situation.. what do you think about it ?

 

[Fishrrman]

I wouldn't buy another battery from that "private seller" again...