Why automatic? Because it automatically starts the charging procedure when battery voltage drops below a certain predefined value and stops after the voltage has risen above the maximum allowed value. Setup can't be easier, just connect two alligator clips to battery terminals and plug the device in mains. This way it can stay connected for months and the battery will neverovercharge. This comes very very handy when you have a scooter or a real motorcycle that you don't drive during the winter time.
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