Bought a new phone battery but doesn't work

[AC Question]

I've had my phone for about a year, and I've decided to buy a new battery because my phone only has about 73% capacity and dies when it's around 30%. So, I just received my new battery and put it in and it does nothing. Won't turn on or even light up when a charger is in it. But it still turns on when the old battery is in it. Any reasons why this could be?

 

[belodion]

One possible reason is that the new battery is bad.