Dual Circuit Plus Battery Switch

Simplifies switching

Isolates engine and house circuits

Combines batteries for emergency starting

Tin-plated copper studs for maximum conductivity and corrosion resistance
ACR Automatic Charging Relay

Automatically combines batteries during charging

Isolates batteries during engine cranking and when not charging

Shares the charge between two batteries more efficiently than a battery isolator

Allows efficient dual battery charging without needing regulator adjustment or rewiring