Inspiron battery replacement

Bought a new battery for the US to replace my existing battery that was completely drained (was receiving battery replacement warnings). Opened the cover, unscrewed the old battery and plugged in the new one on the existing cable circuit. Started the laptop. Battery is operational but the charging is super slow. Battery charges at approx 1% per hour, and its at about 35% right now. Any ideas what might be causing this ? Any help or guidance would be much appreciated!