Deep-cycle auxiliary or leisure batteries need re-charging from mains power when it is available at a site hook-up, from shore-power or at home. Starter batteries, found in your vehicles engine, are constructed differently from leisure batteries and so require a different charging regime.
Intelligent or smart chargers are used to ensure the leisure battery receives a full, deep charge and it's lifetime is maximised. Charging takes place in controlled stages with the voltage level being automatically adjusted throughout to ensure full charge absorption. Fixed voltage battery chargers will not achieve a full re-charge for a leisure battery as the lead plates are thicker. The charger output current should be around 10-20% of your battery's Ah capacity.
IP rating explained, helps you to choose which IP rating you require for your boat or camper project.