Hamolar 12V 120A Starter Relay 2-Pack — 4-Terminal SPST Heavy-Duty Split-Charge Relays with Silver-Plated Contacts

Hamolar’s 2-pack 12V 120A starter relays are heavy-duty SPST switches designed to handle high-current split-charge and starter applications in vehicles and marine craft. These relays combine durable alloy terminals, silver-plated contacts, and flame-retardant housings to deliver reliable make-or-break switching where large currents are involved. Supplied as a twin set, each 4-terminal unit uses a single-pole/single-throw (SPST) configuration rated for 12VDC (14V max) and up to 120A switching, making them a practical upgrade or replacement for automotive, truck, RV, and boat electrical systems.

How does this relay work in split-charge and starter circuits?

The Hamolar relay closes a high-current path when a control signal energizes the coil, allowing power to flow between the battery and the load without routing heavy current through dash switches. Its SPST design creates a straightforward on/off connection suitable for isolating and joining batteries or controlling starter circuits.

• Single-pole single-throw (SPST) 4-terminal layout for clear wiring.
• 120A switching capacity handles starters, winches, and dual-battery systems.
• Operates at nominal 12VDC; safe up to 14V peak.
• Silver-plated contacts reduce resistance and heat under load.

What makes these relays durable and safe for heavy-duty use?

Hamolar builds these relays with high-grade alloy terminals and silver-plated internal contacts that resist corrosion and maintain a firm electrical connection under repeated cycles. The external housing and included gaskets are made of flame-retardant materials to improve lifespan and reduce fire risk in tight engine-bay or bilge installations.

• Alloy terminals for mechanical strength and conductivity.
• Silver-plated contact surfaces for lower electrical resistance.
• Flame-retardant casing to meet demanding environments.
• Sealing gaskets supplied for cleaner, more secure mounts.

How easy is installation and what does the kit include?

Each relay ships with the terminals and gaskets necessary for a straightforward replacement or new installation; the 4-terminal footprint keeps wiring organized. Installers should follow vehicle wiring diagrams and secure heavy-duty cables to the high-current terminals using appropriately sized hardware and insulating boots where needed.

• Includes two relays, matching terminals, and mounting gaskets.
• 4-terminal design simplifies routing for battery, load, and control leads.
• Recommended for use with appropriately sized cable lugs and fuses.
• Suitable for retrofit or OEM-style replacements in vehicles and boats.

Will this relay fit my vehicle, and what precautions should I take?

These Hamolar relays are built to fit standard 4-terminal SPST layouts used across many automotive and marine systems, but confirm terminal spacing and dimensions before replacing an OEM unit. Always disconnect batteries, fuse the high-current feed, and torque connections to the vehicle manufacturer’s recommendations to prevent overheating or arcing.

• Confirm 4-terminal SPST compatibility and physical dimensions first.
• Use a fuse or circuit breaker sized for the load to protect wiring.
• Disconnect batteries before installation to avoid shorts.
• Check terminal torque and use insulating covers if exposed to moisture.

Who is this for? This 2-pack of Hamolar 12V 120A relays is aimed at mechanics, RV and marine owners, fleet technicians, and DIY vehicle electricians who need a robust, high-current switching solution for split-charge setups, starter circuits, winches, or other heavy loads. It’s particularly useful where reliability under frequent switching and resistance to heat and corrosion are required, and for anyone replacing worn relays with a heavy-duty, flame-retardant alternative.

FAQ

Q: Can these relays handle starter motor currents?

A: They are rated for 120A switching and can manage many starter and high-current accessories; confirm your starter’s peak draw before use.

Q: Are these relays waterproof for marine use?

A: The relays include gaskets and a flame-retardant housing but are not guaranteed fully submersible; seal connections for marine installations.