Reponse To Answer

Battery gets used up and there is wear on it. Use HWmonitor to see the wear level of the battery. If is is more than 20%, than try to discard the energy it and charge it again. This will allow for better charging and should lower the wear level. This should be done every so often to get more life out of the battery.Plus battery should be charge only when they are about 15% or less of power left. If you are not using the battery and only have it connect to the power cord, than best practice is to remove the battery until you need to go somewhere that will not be able to use the power cord.