PowerShot SX740 HS battery says it's full but it's almost dead

[pickle]

When I try to charge the battery, it flashes charge, then says full right after. The battery is almost fully dead when this is happening. The camera has no damage, and I have used it for about 5.5 months. How do I get it to charge?

[normadel]

This is a sign that the battery is no good. 

Try leaving it in the charger for a long time, like 8 hours, full day, overnight.