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When your trailer or house battery pulls down the start battery, this isolator charges two batteries from one alternator without connecting them. Its Schottky diode design reduces voltage drop, so both batteries charge while staying separated.
Directly tying a house or trailer battery into your system can leave you with a dead start battery after sitting. This isolator keeps both batteries electrically separate while still charging them from a single alternator, so accessory loads can't pull from your starting battery. You end up with consistent accessory power without risking a no-start situation.
Relay-based setups can allow unwanted current flow between batteries, especially when loads are active. This unit uses Schottky diodes to enforce one-way charge flow from the alternator to each battery, so current can't feed backward into another battery bank. That keeps charging predictable even with multiple loads running.
Traditional diode isolators lose charging voltage, which can leave batteries undercharged. This design keeps voltage drop to approximately 0.3 V at low current and approximately 0.45 V at 80 amps, while a compensation diode slightly increases alternator output to offset those losses. Charging voltage stays closer to what your batteries actually need.
Voltage-sensitive relays and solenoids often require ignition wiring or control signals, which adds complexity and failure points. This isolator operates passively with no switching or trigger input, engaging automatically when alternator output is present. Wiring stays straightforward with fewer components to troubleshoot.
Undersized isolators can overheat or restrict charging when paired with higher-output alternators. This unit is rated for a maximum charge current and alternator current of 80 amps, so it needs to match your system output to avoid becoming a bottleneck. When sized correctly, it maintains steady charge flow without overloading.
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Hi everybody, Andy here with etrailer. Let's take a quick look at this Victron Argo Diode 80-2SC Battery Isolator. Now, this is a battery isolator, specifically as I mentioned, the Argo Diode 80-2SC, and its job is to let you charge two separate batteries from one charging source, like an alternator or a battery charger, all without letting the batteries drain into each other. So, in simple terms, this is gonna be great if you have a setup with a starter battery and a house or auxiliary battery. When the engine is running, both batteries get charged at the same time. But when the engine is off and you're using accessories such as lights, your refrigerator, inverter, whatever, the isolator is going to keep the house battery from pulling power out of your starter battery.
That way, you don't end up stranded with a dead start battery. Now, this model is rated for up to 80 amps, which makes this suitable for many marine, RV, van, and off-grid vehicle applications. It uses high-efficiency Schottky diodes, and that means it has lower voltage drop than older-style diode isolators. It's gonna help your batteries charge more efficiently. Let me go ahead and see if I can give you some measurements just so you have a good idea of the size of this unit.
So looking at what I'm calling the length here, we're sitting pretty close to 4 3/4 inches long. The width, three inches. The height, including up to the terminals, about 2 1/2 inches. It comes with everything that you see here, along with instructions, to guide you through the operation and the installation. Now, if you happen to have any other questions, whether it's about this isolator or anything else that we have here at etrailer, don't hesitate to reach out 'cause ultimately we wanna make sure that you're getting exactly what you need.
Well, again, my name is Andy. Thank you for joining me.
Haven't installed as yet. Plan to charge both Trailer batteries off charge lead from truck. Charge going down the highway.
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Gwendolyn Y.
2/12/2026
Sounds like a great plan, David. Let me know how the install goes and when you get to test it out.