First and the most important thing is you should choose the correct car charger.
Lead-acid car batteries are charged in three stages, namely: constant current, constant voltage and floating charge. When selecting a charger for your car’s battery, pick one that provides the specified charging current and voltage appropriate to the battery type.
Other types such as absorbed glass mat, gel, and flooded battery also have different charging requirements that enable them to provide good service life and optimum performance.
I’ve got the info from those sites, you might refer to those if you’re interested.