VEVOR 12V 140A Split Charge Relay Kit - Dual Battery Isolator, IP65 Weatherproof, Complete Installation Kit

VEVOR's 12V 140A Split Charge Relay Kit is a voltage-sensitive dual-battery isolator that automatically charges a secondary battery while protecting your starter battery from discharge.

This all-in-one split charge relay kit includes the relay module plus cables, terminals, fuses and mounting hardware so you can wire a reliable dual-battery system without sourcing extra parts. Designed for vehicles, marine craft and off-grid setups, the relay connects batteries when charging voltage rises and isolates them as voltage falls, preserving starting power and enabling safe accessory use.

How does the relay decide when to combine or separate batteries?

The relay uses a voltage-sensitive control that closes (combines batteries) at 13.3 V and opens (isolates) at 12.8 V. This automatic cut-in/cut-out behavior lets the alternator charge both batteries during engine run time and prevents accessory drains from discharging the starter battery when the vehicle is off.

• Cut-in voltage: 13.3 V for safe charging engagement
• Cut-out voltage: 12.8 V to protect starter battery reserve
• 5-second delay to avoid rapid switching from transient spikes
• Voltage-sensitive design: no separate control switch required

What electrical capacity and durability can I expect?

This unit handles continuous currents up to 140 A and intermittent peaks to 160 A, making it suitable for most auxiliary battery charging needs in cars, camper vans, boats and light commercial vehicles. Construction uses a shockproof nylon case with IP65 protection for dust and water resistance, so it stands up to engine bays and marine environments.

• Continuous current rating: 140 A; intermittent: 160 A
• IP65 enclosure for dust and water spray resistance
• Power studs: M6 stainless steel for corrosion resistance
• Low standby draw: 8 mA; charging draw: 280 mA

What comes in the kit and how easy is installation?

The kit ships with a complete set of installation components so you can install immediately without hunting for extras: pre-sized battery cables, fused tails, terminals, conduit and mounting screws. VEVOR supplies a drill bit and shrink tube in the package and the relay’s compact footprint allows flexible mounting locations close to batteries or alternator lines.

• Included: relay, six 1 m red cables, one 1 m black ground cable, two 250 mm red cables
• Accessories: positive/negative marine battery terminals, two fuse holders, lug connectors
• Extras: cable ties, shrink tubes, black conduit, drill bit and screws
• Compact size: approximately 2.66" x 2.11" x 2.66" for tight installation spaces

Will this work in marine or off-road environments?

Yes. The relay’s IP65 rating, stainless steel power studs and robust nylon housing make it suitable for dusty, wet or vibration-prone conditions commonly found in boats, overland rigs and work vehicles. Still, install it in a sheltered location when possible and protect exposed fuses and cable runs from direct spray.

• IP65 protects against dust and low-pressure water jets
• M6 stainless power studs resist corrosion near saltwater
• Shockproof nylon plastic withstands vibration and impacts
• Pre-cut cable lengths and conduit simplify protected routing

Who is this for: The VEVOR 12V 140A Split Charge Relay Kit suits vehicle owners who want a straightforward, reliable way to charge a second battery while safeguarding their starter battery. It’s a practical choice for RVers, overlanders, fishermen, small boat owners and anyone adding fridges, winches, inverters or lighting to a vehicle electrical system who needs protected, automated isolation without complex electronics.