1-3-70 Battery Isolator
This heavy-duty isolator allows charging multiple batteries automatically from one or two alternators and prevents the discharge or ‘dumping” of one battery into another. Each battery is charged according to its need without overcharging and is rated for 12-, 24-, or 36-volt negative ground DC systems.
Features:
- Conservatively rated diodes and a rustproof anodized aluminum heat sink case.
- Heavy-duty construction
- Rated for systems up to 48 volts DC, negative ground
- Rust-proof anodized aluminum case
- Stainless steel mounting hardware is provided
- Protective covers are provided for terminals
Specifications:
- Alternator Sources: 1
- Battery Bank: 3
- Max. Amperage Input Capacity: 70
- Stud Terminal Size: 6mm
- Dimensions (L x W x H): 3.25 x 4.5 x 3.1 inches
- Weight: 2 lbs.
- Operating Temperature: -40 to +80 degrees
- Duty Cycle: Continuous rating to 50 degrees C Derate linearly to 70% @ 80 degrees C.
- Temp. Rise: 5 degrees C at full rated current (mount vertically for optimum cooling)
- Voltage Drop: 0.7V @ 50% load, 0.9V @ full load
*Note: These battery isolators are not compatible with self-exciting alternators. The alternator must have an external excitation lead. Please consult the manufacturer of your alternator if you are unsure of your configuration
This product may not be returned to the original point of purchase. Please contact the manufacturer directly with any issues or concerns.


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We ship via UPS, FedEx, and USPS . Orders are processed in 1–2 business days with typical delivery in 1–5 business days .
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Returns accepted within 30 days of delivery. Items must be unused and in original packaging.
- Mistaken or damaged cargo? We’ll handle return shipping.
- Changed your course? Return shipping is on you.
- Report defects or damage within 7 days for a free exchange.
💰 Anchor Your Refund
Refunds go back to your original payment method within 5–7 business days after inspection.
📨 Contact the Crew
Questions about your order? Drop anchor at sales@marineelec.com .
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