All converters are also battery chargers, some are better chargers than others. Older converters such as the Magnetek/Parallax series are fixed voltage. Not high enough to charge very fast but high enough to boil the battery fluid.
Modern converters are 3 or 4 stage that start at a high voltage to charge the battery fast, then reduce the voltage to maintain the battery without boiling away the fluid.
The Progressive 9100 series is a modern converter and has been replaced with the 9200 series that has the wizard built in. It is one of the best.