Angelina Jolie

I am having a very tough time with my psp battery?

I just got a psp battery from ebay today. for some reason when i plug it in to the charger it says it’s charging i read on the psp 100 percent but then the drains and the light starts blinking. i don’t know if it’s the battery because the battery it’s a brand new 3600mAh 3.6V model psp – S360. by the way i have a psp 1001 running on cfw 5.50 gen d3. I don’t have the original battery because i converted it to a pandora battery. Help please