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Upgrade your power system with the reliable Newmar 1-2-70A battery isolator, designed to seamlessly charge two battery banks from a single alternator source. This heavy-duty unit prevents one battery from draining into another, ensuring your starting battery stays ready while fully charging your house or auxiliary bank. Perfect for demanding environments like marine vessels, RVs, and off-grid setups, it intelligently prioritizes charging based on each battery's needs without risking overcharge.
Built for real-world reliability, the 1-2-70A handles 12-48V negative ground DC systems and supports up to 70 amps, making it ideal for alternators in that range. Its diode-based design offers straightforward operation—no relays to fail, no complex electronics to troubleshoot.
When your engine runs and the alternator kicks in, power flows through high-efficiency diodes to both batteries. The isolator blocks reverse current, so if your house battery is in use (like running lights or appliances), it won't pull from the starting battery. This setup extends battery life, reduces alternator wear, and keeps you powered without interruptions. Mount it vertically for best heat dissipation, and you're set for years of trouble-free service.
Engineered for efficiency and durability:
| Model | Alternator Sources | Battery Banks | Max Input Capacity (Amps) | Weight (lbs/kg) | Dimensions (L x W x H inches) |
|---|---|---|---|---|---|
| 1/2/70A | 1 | 2 | 70 | 2 / 0.9 | 3.25 x 4.5 x 3.1 |
Unlike solenoid-based switches that can stick or wear out, diode isolators like the Newmar 1-2-70A provide passive, always-on protection with minimal voltage drop. Users in boating forums rave about its simplicity—no programming, no buttons to fail. It's a go-to for separating cranking and deep-cycle batteries in RVs, yachts, work trucks, and solar-hybrid systems. Pair it with your alternator for balanced charging that maximizes runtime and reliability.
Connect the alternator output to the common terminal, then route to each battery bank. Use appropriately sized cables (at least 6 AWG for 70A) and fuses near batteries for safety. Vertical mounting enhances cooling—keep it away from exhaust heat. Test by checking voltage at each bank with the engine running and off. It's plug-and-play for most setups, saving hours compared to custom wiring.
It indicates 1 alternator input charging 2 battery banks at up to 70 amps continuous rating.
Yes, it's rated for 12-48V negative ground DC systems, making it versatile for various vehicles and vessels.
Diodes block reverse current flow, so one battery can't drain into another when the alternator is off.
Expect 0.7V at 50% load and 0.9V at full 70A—minimal impact on charging efficiency.
Absolutely, with an operating range of -40°C to +80°C and built-in heat sinking for continuous duty.
Yes, stainless steel hardware and protective terminal covers are provided for secure, safe installation.
It pairs well with lead-acid and AGM; for lithium, ensure your alternator and charging profile match to avoid issues.
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| Performance Specifications Operating temper ature: -40 to +80°C
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Ships within 48 hours · Estimated delivery Jun 28 - Jul 3
US$40
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