Mavnai Towed Vehicle Charge Line Kit 156-25 — 14‑Gauge 7' Red Harness with Thermal Circuit Breaker

The Mavnai Towed Vehicle Charge Line Kit (156-25) is a ready-to-install trailer charging harness that supplies up to 15 amps of maintenance charging to your towed battery while towing, using heavy-duty 14-gauge wire, a thermal circuit breaker, and a mounting kit.

Keep your trailer or RV battery topped up on the road without needing a separate onboard charger. This kit combines a durable 7' red power wire, protective split loom, ring terminals and a thermal circuit breaker so you can route a safe, steady maintenance current from your tow vehicle to the trailer battery. The components are sized for continuous charging at modest current levels and are intended to reduce battery discharge from parasitic loads and long-term storage between uses.

How does this kit maintain a trailer battery while towing?

The kit delivers a low, regulated maintenance current (up to 15 amps) from the tow vehicle to the trailer battery, helping offset drain from lights, refrigerators or accessories. It is not a high-capacity fast charger but is meant to keep a healthy state of charge during transit.

• Provides up to 15 amps of continuous maintenance charging
• 14-gauge conductor balances current capacity with flexibility
• Thermal circuit breaker prevents overheating and overloads
• Ring terminals and mounting hardware ensure secure connections

What components are included and why are they important?

The kit ships complete so you can install it without sourcing additional parts. Each piece is chosen to create a reliable path for current, protect the circuit from faults, and make mounting straightforward inside the tow vehicle or trailer compartment.

• 7' red power wire — long enough for most engine bay-to-battery runs
• Split wire loom and cable ties — protect wiring from abrasion and routing
• Thermal circuit breaker — automatic protection against overloads
• Three ring terminals and mounting kit — durable connection points and tidy installation

How safe and durable is the installation for regular towing use?

Safety and longevity were prioritized through the selection of 14-gauge heavy-duty wire and a thermal breaker designed for continuous small-current duty. Correct installation prevents hot spots and loose connections that could cause voltage drop or component stress.

• Heavy-duty 14-gauge wire resists wear and reduces voltage drop
• Thermal breaker trips under excessive load to protect wiring and battery
• Split loom shields against chafing at mounting points
• Included hardware secures components to limit vibration fatigue

Who is this for? The Mavnai 156-25 Towed Vehicle Charge Line Kit is designed for RV owners, trailer haulers, and DIY installers who want a simple, dependable way to maintain a trailer battery while on the road. It suits users who need a plug-and-play wiring solution with built-in overload protection and enough flexibility to route through standard engine bays and trailer compartments. If you routinely tow and want to minimize battery drain from accessories or long idle periods, this kit provides a practical maintenance charging path without the complexity of an onboard charging system.