Newmar 2-3-120 Battery Isolator

Ensure reliable and efficient power management on your vessel with the 2-3-120 Battery Isolator. Specifically designed for marine and boating applications, this heavy-duty isolator automatically charges multiple batteries from one or two alternators while safeguarding against battery discharge or “dumping.” Each connected battery receives tailored charging, preventing overcharging and optimizing the performance of 12-, 24-, or 36-volt negative ground DC systems.

Key Features

• Durable Construction: Built with conservatively rated diodes and a rustproof anodized aluminum heat sink case to withstand harsh marine environments.
• Heavy-Duty Performance: Engineered for robust performance, ensuring long-lasting reliability for your boat’s electrical system.
• Versatile Voltage Ratings: Compatible with DC systems up to 48 volts, negative ground, catering to a wide range of marine applications.
• Corrosion-Resistant Design: Rust-proof anodized aluminum case provides excellent resistance against saltwater and moisture exposure.
• Easy Installation: Comes with stainless steel mounting hardware for secure and straightforward installation on your vessel.
• Safety Enhancements: Protective covers included for terminals to prevent accidental short circuits and ensure safe operation.

Technical Specifications

Specification	Details
Alternator Sources	2
Battery Bank Capacity	3
Maximum Amperage Input	120 A
Stud Terminal Size	6 mm
Dimensions (L x W x H)	12.5 x 4.5 x 3.1 inches
Weight	5 lbs
Operating Temperature Range	-40°C to +80°C
Duty Cycle	Continuous rating up to 50°C, derates linearly to 70% at 80°C
Temperature Rise	5°C at full rated current (mount vertically for optimal cooling)
Voltage Drop	0.7V at 50% load, 0.9V at full load

Important Note

Compatibility: The 2-3-120 Battery Isolator is not compatible with self-exciting alternators. It requires an alternator with an external excitation lead. Please consult your alternator’s manufacturer if you are uncertain about your alternator’s configuration.

Download the Quick Guide (PDF)

Orders of physical products placed by 3 PM EST M-F typically ships the same day, if all requested items are in stock. Weekend orders will typically ship on Monday.

Shipping takes 2-7 days.

We currently ship to the Contiguous 48 States.

Life of Sailing merch is custom made for the customer after an order is placed. Total turnaround is typically 7-14 days from order to doorstep.