battery problem?

[GreenAcid]

Ok. So last night my phone charged to 100% so i took it off the charger. Woke up about 8 hours later and
The battery was at 10%.

Uh. Should i swap out?

 

[Edi]

Mine took a few charges (go from 100% to where the phone shuts off) to fully get a good reading, after a week I've been able to get a full days use (6am till 11pm of light to medium use) and still have 10-20% left.