Before buying a charger, identify three battery specifications: nominal voltage, battery type and capacity in amp-hours, or Ah. Check the label and battery documentation. The charger must match the particular battery, rather than merely carry a motorcycle description.
AGM, gel and conventional flooded lead-acid batteries can require different charging settings. A LiFePO4 battery needs charging designed for that chemistry. Lead-acid and lithium modes are not interchangeable, even when both batteries have a nominal rating of 12 V.
Check the charger’s supported Ah range and the battery’s permitted charging current. A high-output car charger can damage a small motorcycle battery if it supplies excessive current. Follow the battery manufacturer’s specifications; a larger amp rating is not an advantage in itself.
For extended connection, choose a suitable maintenance mode and confirm that the manufacturer permits that use. A basic continuous trickle charger can overcharge a battery. Also check the connection procedure in the instructions: switch the charger off before attaching or removing clamps, and charge in a well-ventilated place.