VEVOR 12V 140A Split Charge Relay Kit — Dual Battery Isolator, IP65 Marine-Grade with Full Install Kit

VEVOR's 12V 140A split charge relay kit is a voltage-sensitive dual battery isolator system that charges a starter and auxiliary battery simultaneously while preventing one battery from draining the other.

If you run accessories from a secondary battery in a camper, boat, or 4x4, this kit provides an automatic way to share alternator charge without risking a flat starter battery. The relay monitors voltage and closes at 13.3V to allow charging, then opens at 12.8V to isolate batteries when charging falls below the threshold. Built for exterior and marine use, the relay is IP65-rated and packaged as a full-install kit with cables, terminals, fuses, and mounting hardware.

How does the relay decide when to connect my batteries?

The VEVOR voltage sensitive relay uses preset voltage thresholds to manage battery connection automatically. When alternator output raises system voltage to 13.3V the relay closes to let the alternator charge both batteries; it reopens at 12.8V so the starter battery stays protected when the engine is off.

• Cut-in voltage: 13.3V — enables charging of both batteries
• Cut-out voltage: 12.8V — isolates batteries to preserve starter power
• Delay time: 5 seconds — avoids toggling from brief voltage spikes
• Continuous current capacity: 140A with 160A intermittent support

What’s included and will I need extra parts?

The kit arrives ready to install for most installations; VEVOR supplies the relay plus a comprehensive set of cables, terminals, fuses and mounting accessories so you typically won’t need additional components. You may only need vehicle-specific conduit or longer cable runs for remote battery locations.

• One voltage sensitive split charge relay (model JDQTJ-6M)
• Six 1 mtr red 110A battery cables and black 1 mtr ground cable
• Marine battery terminals, fuse holders, lug connectors, shrink tube
• Drill bit, screws, split conduit and 15 cable ties for tidy routing

Is this relay durable enough for off-road or marine use?

Yes — the relay housing is shockproof and dust-resistant, made from robust nylon plastic, with an IP65 waterproof rating to resist spray and dust. It’s suitable for vibration-heavy and outdoor installations like off-road vehicles, RVs and boats, although final placement and proper mounting are important to maximize longevity.

• IP65 rating — protected against dust and low-pressure water jets
• Nylon plastic construction — impact and vibration resistant
• Stainless steel M6 power studs for corrosion resistance
• Low standby draw of 8mA to minimize parasitic drain

How much electrical load can it handle and what are the power characteristics?

The relay is rated for continuous 140 amps with short intermittent capacity to 160 amps, which covers most alternator outputs for common camper and light-commercial setups. Electrical draws are low when idle and moderate during charging, so it’s efficient for long-term installations.

• Continuous current: 140A, intermittent: 160A
• Charging current draw: 280mA during activation
• Standby current draw: 8mA minimizing battery drain
• Compact size (2.66" x 2.11" x 2.66") for flexible mounting locations

Who this is for: This VEVOR split charge relay kit is aimed at vanlifers, 4x4 and tow-vehicle owners, marine enthusiasts, and anyone who runs lights, fridges or winches from an auxiliary battery. If you want automatic charging control, reliable isolation to protect your starter battery, and a full accessory pack to simplify installation, this kit is designed to meet those needs without extensive additional parts.