The right caravan split charge relay keeps your primary vehicle battery charged while safely powering an auxiliary battery. This guide highlights five reliable options, explaining who each is best for and why. Ideal buyers include full-timers seeking robust high-amperage performance, weekend travelers needing simple installs, and those upgrading older towing electrics. The following table summarizes the top picks to help you compare at a glance.
| Product | Best For | Key Feature |
|---|---|---|
| VEVOR Split Charge Relay Kit | All-around use in RVs, boats, trucks, caravans | 140A voltage-sense relay with 13.3V/12.8V cut-in/cut-out |
| True Mods 12V DC 120A Relay | High-current setups for trucks and marine apps | Continuous duty 120A rating, 4-pin SPST |
| POWO Carlife 140A Kit | Longer cable runs and dual-battery charging | 16.4 ft cable kit, intelligent voltage sense |
| Hamolar 200A Relay (2 Pack) | High-current, versatile 12V/14V max applications | Two relays per pack, 200A capacity |
| AB Tools 30A Automatic Relay | Smaller loads or lighter tow setups | Automatic voltage sense, ignition-controlled |
VEVOR Split Charge Relay Kit
The VEVOR kit uses a dual battery isolator that engages at 13.3 volts and disconnects at 12.8 volts, keeping the main starting battery ready. It supports charging two batteries simultaneously and isolates them when the vehicle is off. This is best for users needing a robust, all-in-one solution with straightforward installation. Caveat: simpler systems may suffice for lighter loads, but this kit is designed for higher-demand setups.
True Mods 12V DC 120 Amp Split Charge Relay
This 120A continuous-duty relay is ideal for trucks and marine applications requiring reliable high-current performance. Its 4-pin SPST design and normally open configuration support straightforward integration with existing tow or vehicle electrical systems. Choose this if you need steady high-current operation and a simple on/off control tied to ignition. Limitation: 120A may be insufficient for very large auxiliary battery banks paired with high-draw gear.
POWO Carlife Battery Isolator Kit
The POWO Carlife kit includes a 16.4-foot cable run and a smart voltage-sensitive relay that can charge two batteries from the engine alternator simultaneously. It is well-suited for users with longer installation runs or those needing extended cable reach between the engine bay and auxiliary battery location. Best for: caravans and RVs with extra distance between batteries. Note: longer cables require careful routing to avoid damage or interference.
Hamolar 2 Pack 200A Continuous Duty Relays
The Hamolar relays provide a high 200A switching capability with durable alloy terminals and silver-plated contacts. They are suitable for universal 12V applications, including split charging and other automotive uses. Best for: users with demanding electrical loads or those needing a spare high-capacity relay. Caution: ensure the wiring harness can accommodate the 200A capacity and heat dissipation requirements in tight spaces.
AB Tools Automatic Voltage Sense 30A Relay
This AB Tools 30A relay switches on and off with the tow vehicle ignition and automatically senses charging voltage. It is well-suited for lighter towing electrics and smaller auxiliary battery setups. Best for: drivers needing a compact, ignition-controlled relay for modest electrical demands. Limitation: 30A capacity may restrict use with larger auxiliary battery banks or high-draw accessories.
Buying Guide
What should you look for when choosing a caravan split charge relay?
- Current rating: Match the relay’s amperage to your auxiliary battery needs. Higher capacity prevents overheating and improves reliability for high-draw loads.
- Voltage sensing: Look for voltage-sense or smart relays that automatically connect/disconnect based on battery voltage to protect the starting battery.
- Cable length: Longer cable runs require more robust cable kits. A kit with extended cables helps accommodate distant battery placements.
- Installation complexity: Some kits include everything needed for a quick install; others require additional wiring or fuses. Choose based on your comfort level.
- Durability: Weather-resistant enclosures and durable contacts extend life in outdoor or vehicle environments.
How do you plan to use the system?
- Full-time RV or boat: Prioritize high-current capable relays (100A+), with voltage-sense and robust build.
- Casual towing: A smaller, easy-to-install relay with ignition sensing may suit light loads.
- Long cable routes: Choose a kit with a longer cable assembly to minimize splicing and ensure clean routing.
FAQ
- What is a split charge relay used for in caravans?
It automatically charges an auxiliary battery from the vehicle’s alternator while protecting the starting battery from deep discharge.
- Do I need a high-amp relay for an RV with multiple accessories?
Yes, high-amp relays (100A or more) better support multiple devices like inverters, fridges, and water pumps without overheating.
- Is professional installation necessary?
Not always. Many kits are designed for DIY installation, but professional wiring is recommended for complex setups or extended cable runs.
- How do voltage-sense relays decide when to connect?
They monitor the main battery voltage and connect the auxiliary battery when voltage is high enough, and disconnect when voltage drops to protect the main battery.
- Can a relay fail and damage the battery system?
Relays are designed to be rugged, but improper wiring or undersized components can cause overheating or improper charging. Follow instructions and rated specifications.