The Victron Argodiode 140-3AC is a diode-based battery isolator built for 12V, 24V and 48V systems where a single alternator needs to charge up to three independent battery banks at once. It suits marine, vehicle and off-grid setups where stopping one bank discharging into another is essential.

Key features

• Rated current, 140A continuous, for high-demand charging systems with large alternators.
• Three battery outputs, one alternator input can charge up to three separate banks with full electrical isolation between them.
• Diode isolation, prevents any bank discharging into another regardless of state of charge differences.
• System voltage, compatible with 12V, 24V and 48V DC systems.
• Construction, aluminium heat sink body with busbar-style connections.
• Weight, 1kg, supplied in retail packaging.

How it works

Schottky diodes split the alternator output between the three battery banks without any electronic switching or control wiring. Current flows from the alternator input to each output independently, so a fully charged bank cannot back-feed a depleted one. The trade-off is a voltage drop across each diode, typically 0.5V to 0.7V under load, meaning battery terminal voltage sits slightly below the alternator's output. This can be compensated by raising the regulator set point, or by configuring a Victron battery charger or MPPT controller to allow for the offset. It is worth factoring into system design for AGM or lithium banks with tighter charge voltage tolerances. The 140A rating is the total input current; how it splits across the three outputs depends on the relative state of charge and internal resistance of each battery.

Applications

• Marine vessels with separate starter, domestic and bow-thruster banks charged from one alternator.
• Motorhomes and campervans isolating the starter battery from leisure banks.
• Off-grid cabins or vehicles with alternator charging feeding multiple banks.
• Commercial vehicles keeping auxiliary banks isolated from the engine start battery.
• Retrofits replacing older split-charge relay systems with diode isolation.

Installation notes

Fitting should be done by a qualified auto-electrician or marine electrician working with high-current DC systems. Mount the unit where airflow around the heat sink is unobstructed, since thermal performance relies on passive convection. Cabling must be rated for 140A continuous use, with correct fusing on the alternator feed. Allow for the diode voltage drop when setting alternator or regulator voltage, particularly with AGM or lithium chemistries. Marine installs should follow NMEA or RYA wiring guidance as applicable.

What's in the box

• 1 x Victron Argodiode 140-3AC diode battery isolator (retail packaging)