Split Charge Relay VSR 12V 140A 140 AMP 0-727-33 Smart Dual Battery Isolator Portable Power Voltage Sensitive For Camper Car RV

12V, 140A rated voltage sensitive relay for split charging applications in camper vans, motorhomes, 4x4s and boats. Allows charge to flow into one battery (or bank of batteries) only when a charging voltage is detected at the other battery (dual sensing operation).

Dual sensing operation - charges from starter battery to leisure battery when alternator is running and charges from leisure battery to starter battery when mains charger is connected.

Relay connects when sensed voltage reaches 13.3V or higher
Relay disconnects when sensed voltage drops to 12.8V or lower

Maintains battery isolation when not charging, so starter cannot be drained by leisure use and vice-versa.
Ignition protection to UL1107
Fully automatic operation
CE approval

Virtually zero voltage drop
Protects sensitive electronic equipment from harmful engine start-up spikes
Well proven design with 1000s of units operating in the field
Terminal connections marked on inside of unit for easy installation
Note: The benefit of this type of relay is that it does not require a connection to the alternator or any modifications to the existing vehicle electrical system.  Simply connect the +ve terminals on each of your batteries to the terminals on the relay and the black relay wire to a common -ve point.

An LED indicates when the relay is ON (contacts closed). Fixing holes in the body allow the unit to be mounted to a bulkhead and body cut-outs offer various cable routing options.

Fully encapsulated electronics make this unit splashproof and particularly suitable for harsh environments (marine use, vehicle engine bays etc.)

Sold individually. 
IMPORTANT NOTE: These relays are not suitable for vehicles with 'smart' or 'intelligent' alternators. As a guide this applies to vehicles having engines that comply with Euro5 emissions standards and onward, often also incorporating regenerative braking (if in doubt please consult your vehicle manufacturer to confirm). If your vehicle has a smart alternator then you will need to use a battery-to-battery charger instead of a VSR