It's not the battery, it's because if inside there are 2 pin holes and at the bottom there is 2 pins that have to be pressed when making a connection to the port where the battery pins are, so when you plug in your charger it sounds like either the charging port is damaged or the pins are not making the connection, the blinking light is only showing that it making a connection to the metal inside the pinholes( you can just about see 2 gold metal pieces near the top of the pinholes) but you won't get a charge from it , it will only show the light blinking because it's trying to find a charge and because it's not making the connection its cutting off hence the blinking light. Hope this helps in more detail for
