Victron ARG200301020 - ARGOFET 200A 3-Battery FET Isolator

VICTRON ARG200301020 - ARGOFET 200A 3-Battery FET Isolator

Advanced FET battery isolator enabling simultaneous charging of three batteries from single alternator or battery charger without connecting batteries together featuring virtually zero voltage loss with less than 0.02V drop at low current and 0.1V average at higher currents, 200A continuous current capacity, alternator energize input with current limiting for alternators requiring B+ voltage to initiate charging, prevents accessory battery discharge from affecting starter battery, superior performance compared to traditional diode isolators eliminating need for alternator voltage increase, ideal for dual battery systems, 4WD touring setups, marine vessels, caravans, motorhomes, work vehicles, and applications requiring independent battery banks for accessories, winches, fridges, lighting, and auxiliary equipment while protecting engine starting battery.

Product Overview

The Victron ARG200301020 ARGOFET 200A is an advanced FET (Field Effect Transistor) battery isolator engineered to enable simultaneous charging of up to three independent battery banks from a single alternator or battery charger without electrically connecting the batteries together, preventing discharge of one battery from affecting others. Unlike traditional diode battery isolators that suffer 0.6-0.8V voltage loss significantly reducing charging efficiency, the ARGOFET utilizes FET technology achieving virtually zero voltage drop - less than 0.02V at low currents and averaging only 0.1V at higher currents. This minimal voltage loss eliminates the need to increase alternator output voltage maintaining factory charging profiles while ensuring batteries receive full charging voltage for optimal battery health and lifespan. The alternator energize input with current limiting solves the common problem where alternators require DC voltage on B+ terminal to begin charging - when diode or FET isolators are installed, no return voltage reaches B+, preventing alternator startup. The ARGOFET's energize input powers B+ when the engine run/stop switch closes, enabling proper alternator operation in all vehicle configurations.

Important Notes:

Cable Sizing Critical: Short cable lengths with adequate cross-section essential. Example: 100A through 50mm² cable for 10m creates 0.26V drop. Use appropriately sized cables.

Professional Installation Required: Alternator integration and multi-battery systems require automotive electrical expertise ensuring correct connections and alternator energize wiring.

Not Battery Charger: Isolator manages charging from existing alternator or charger. Does not generate charging current itself.

Alternator Compatibility: Verify alternator has external regulation compatible with isolator installation. Some smart alternators may require additional configuration.

Three Battery Maximum: Isolates up to 3 batteries. For more batteries, consider multiple isolators or different battery management solutions.

Key Features

Minimal Voltage Loss - <0.02V at low current, 0.1V average at high current - superior to 0.6-0.8V loss in diode isolators.

200A Continuous Current - Handles high-output alternators and heavy charging demands in demanding applications.

3-Battery Isolation - Charges three independent battery banks simultaneously without connecting batteries together.

Alternator Energize Input - Current-limited input powers alternator B+ terminal enabling charging with alternators requiring B+ voltage.

No Alternator Modification - Factory alternator voltage suitable due to minimal voltage loss eliminating need for voltage increases.

Prevents Cross-Discharge - Discharging accessory batteries won't affect starter battery ensuring reliable engine starting.

FET Technology - Solid-state Field Effect Transistor design provides reliability and efficiency superior to diode technology.

Dual Battery System Ready - Perfect for 4WD dual battery installations separating starting and auxiliary batteries.

Marine Applications - Ideal for boats with house battery and engine starting battery requiring independent charging.

Caravan/Motorhome Compatible - Charges vehicle battery and caravan/RV house batteries simultaneously from alternator.

Protects Starter Battery - Running accessories, fridges, winches, or lighting won't drain starting battery preventing being stranded.

Independent Battery Banks - Each battery operates independently - failure of one doesn't affect others.

High Efficiency - Minimal voltage loss maximizes charging efficiency and battery lifespan.

VICTRON Quality - Premium European engineering with proven reliability in demanding marine and automotive applications.

Compact Design - Space-efficient housing suitable for engine bay or equipment compartment installation.

Technical Specifications

Frequently Asked Questions

Q: What's the difference between FET isolators and traditional diode isolators?

A: Traditional diode isolators create 0.6-0.8V voltage drop significantly reducing charging voltage reaching batteries - this requires increasing alternator output voltage and still results in undercharged batteries shortening lifespan. FET isolators like the ARGOFET have virtually zero voltage loss (<0.02V low current, 0.1V average high current), allowing factory alternator voltage to properly charge batteries without modification. This maintains optimal battery charging profiles, extends battery life, and eliminates the need for alternator regulator adjustments.

Q: Why is cable sizing so important with FET isolators?

A: Because FET isolators have such minimal voltage loss (0.1V), cable voltage drop becomes the dominant factor affecting charging efficiency. Example: 100A through inadequate 10mm² cable for 10m creates 1.3V drop - far exceeding the isolator's 0.1V loss. Using proper cable sizing (50mm² for 100A over 10m creates only 0.26V drop) maintains the efficiency benefits. Professional installers use voltage drop calculators ensuring adequate cable cross-section.

Q: What does the alternator energize input do, and do I need it?

A: Many modern alternators require DC voltage on the B+ terminal to begin charging. When you install a battery isolator between alternator and batteries, no return voltage flows back to B+, preventing the alternator from starting. The energize input solves this by providing current-limited DC to B+ when your engine run/stop switch closes, allowing normal alternator operation. If installing the isolator stops your alternator from charging, connecting the energize input to your ignition circuit solves the problem.

Q: Can I use this for a dual battery system in my 4WD?

A: Yes, the ARGOFET 200A is excellent for 4WD dual battery systems where you need a starting battery and separate auxiliary battery for camping accessories, fridges, lighting, and recovery equipment. Connect alternator output to isolator input, then one isolated output to starter battery and another to auxiliary battery. When engine runs, both batteries charge simultaneously. When engine is off and you use auxiliary battery for camping, the starter battery remains fully charged ensuring reliable starting.

Q: Will this work with my lithium auxiliary battery or AGM batteries?

A: Yes, the ARGOFET's minimal voltage loss makes it suitable for modern battery chemistries including AGM, gel, and lithium batteries requiring precise charging voltages. However, the isolator doesn't control charging voltage or profiles - it simply distributes alternator output to multiple batteries with minimal loss. For lithium batteries specifically, ensure your alternator output voltage is compatible with lithium charging requirements (typically 14.2-14.6V), or install a DC-DC charger between isolator output and lithium battery for proper charging profiles.