When the engine is started the starting battery and auxiliary batteries are separated allowing only the starting battery to be charged. When the charge voltage reaches 13 3 volts the voltage sensitive. A vsr voltage sensitive relay is perfect for dual battery systems. 
				
			
										berkley jensen outdoor furniture covers
											best box spring for memory foam mattress
											best car air purifier for smoke
											best door decorations for christmas
											best finish for wood front door
											best way to resurface kitchen cabinets
											best buy walk in bathtubs
											best water softener systems