Try giving it a full charge on a smart charger before use, as you ideally should with any new battery. Before installing and after a rest period of a few hours, check battery volts at terminals. You should see minimum of 12.7 volts.

Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone