macallister COD18VCN batteries replacement
 

I have an 18 volt cod 18vcn macallister nailer with charger & 2 x batteries but it appears to not charge to sufficient power. It is as new & barely used but age unknown. Are battery replacements available or what can I do to reload battery packs? Also saw picture of multi tool pack with nailer cod 18ucn,, Is this the same battery?
Are there any other makes with interchangeable battery?