Battery warning on startup

I recently replaced the battery on my Inspiron 3543. Every time on startup if the adapter is plugged in I get the warning:
"The battery is not recommended for this system. The system will unable to charge this battery. Strike the F1 key to continue, F2 to run setup the utility."

When turned on the battery simply won't charge. When the system is turned off it occsionally charges and occassionally doesn't. Is the problem with my new battery or would it be something else?
Any help would be really appreciated.