Adding a second battery to the electrical system prevents the unintended discharge of the engine start battery. Blue Sea Systems smaller, more compact version of the popular Add-A-Battery kit to its product offering was primarily designed for outboard powered boats with alternator output of 65A or less. When installed, the Mini Add-A-Battery isolates the start battery from the house loads which prevents the discharge of the start battery. The Mini Add-A-Battery offers a simple way to control the charging and battery switching of two battery banks. The M-Series Dual Circuit Plus Battery Switch simplifies the switching while the M-ACR automates charging between two batteries.