7.1.6. Wet Marine/RV
Wet marine/RV batteries are available in three different versions--starting, "dual purpose", and deep cycle. The wet marine/RV starting battery is basically a wet car (or starting) battery with carrying handles and stud or combination terminals and designed for high current and shallow discharges (up to 5% Depth-of-Discharge). It maybe ruggedized to be more resistant to vibration and shock than an automobile battery. The battery's construction, separator thickness and material, plate thickness and plate composition will all determine a battery's ability to withstand vibration. Securing the battery to reduce the vibration will increase it's service life.
The wet "dual purpose" marine/RV battery is a compromise between a starting and deep cycle battery that is specially designed for high vibration in marine/RV applications. It is generally are more expensive than a starting battery. The marine/RV deep cycle battery is designed for deep discharge applications, such as a running a trolling motor. Marine starting, "dual purpose", or deep cycle batteries can have wet Standard (Sb/Sb), wet Low Maintenance (Sb/Ca), or wet "Maintenance Free" (Ca/Ca) plate formulations. Please beware of marine/RV batteries that are cheap, because they are often car batteries with handles and stud or combination terminals. A marine/RV deep cycle or "dual purpose" battery will work as a starting battery if it can produce enough current to start the engine. Good ventilation is required for all wet (or "flooded") batteries to dissipate the gasses produced during charging. For saltwater applications, use ONLY sealed AGM (Ca/Ca) or Gel Cell (Ca/Ca) VRLA batteries to prevent the formation of DEADLY chlorine gas if battery electrolyte is mixed with saltwater.
