MaySpare 80A 12V Continuous-Duty Solenoid Relay — Battery Isolator for Dual Battery Systems, Heavy-Duty Copper Contacts

MaySpare 80-Amp 12V continuous-duty solenoid is a heavy-duty relay designed to isolate and manage dual battery systems while handling sustained high currents.

If you need a compact, rugged relay to split or protect auxiliary batteries, this MaySpare 80A solenoid offers continuous 12V operation with high surge tolerance and long mechanical life. Built for vehicle, marine, and off-grid applications, it simplifies adding a second battery or controlling high-current accessories without rewiring the primary system.

How does this relay protect and isolate a secondary battery?

The relay separates the starter battery from the auxiliary bank until you want them linked, preventing unwanted discharge of the primary starting battery. When activated, it closes copper-to-silver contacts to pass current; when open, the batteries are electrically isolated.

• Continuous current rating: 80 A for steady loads.
• Short surge capability: up to 150 A for brief inrushes.
• Copper contacts with silver-plated pins reduce resistance and arcing.
• Normally open configuration for safe default isolation.

What are the electrical and durability specifications I should expect?

This solenoid is rated for 12 VDC systems and can carry 80 amps continuously, with short-duration handling up to 150 amps. It is engineered for long service life with a mechanical endurance around 100,000 cycles under normal operating conditions.

• Voltage compatibility: 12 VDC automotive/marine systems.
• Continuous duty: 80 A; surge handling: 150 A brief pulses.
• Switching capability supports loads up to approximately 2000 W.
• Durability: circa 100,000 mechanical cycles for repeated use.

How do I install and wire the MaySpare 80A relay?

The product ships with mounting hardware and a set of terminals to simplify installation. Four larger 100 A terminals are provided for the high-current load connections, while four smaller terminals tie into the vehicle or system control circuits.

• Includes 4 large 100 A terminals for battery/load connections.
• Includes 4 small control terminals for original wiring integration.
• Comes with four insulated red caps to protect exposed posts.
• Designed for bolt-on mounting and standard 12V control activation.

Can this relay run continuously, and are there application limits?

The relay is rated for continuous operation at its 80 A specification, but thermal and environmental conditions affect real-world duty cycles. For extended heavy use, allow periodic cooling breaks per system demands; some installations note continuous runs of several hours before rest is advisable.

• Continuous use supported at rated current, but heat buildup is a factor.
• Recommended to monitor temperature during prolonged high-current draws.
• Suitable for alternator charging, accessory circuits, and battery isolating.
• Compatible as a replacement for several industrial relays and OEM part numbers.

Who is this for: Technicians, RV and boat owners, overlanders, electricians and hobbyists who need a dependable, serviceable solution for adding or protecting auxiliary batteries and high-current circuits. The MaySpare 80A relay is aimed at installations that prioritize reliability, simple wiring, and rugged components for automotive, marine, and off-grid power setups.