Victron Autotransformer: Split-Phase Setup
Updated 16 September 2026 · By SolarNevs Research Desk, Dealer surveys + verified sources · 1 source · Method ↗
Key Takeaways
- The Autotransformer 50 A 100 A provides high-efficiency split-phase 120/240V balancing and voltage stepping.
- Universal voltage flexibility: Input/output Voltage 120 / 240 V.
- Built-in breaker protection: Input Circuit Breaker 50A, Two Pole 100A, Two Pole.
- Line frequency support: Frequency 50/60Hz.
- Full 240V power transfer: Maximum 240 V Feed Through Current 50A 100 A.
- Sustained neutral balancing: Neutral Current, Continuous 45A @ 40°C/100°F.
- Short-term peak imbalance headroom: Neutral Current, 30 min 55A @ 40°C/100°F.
- Low-noise magnetic engineering: Transformer Type Toroidal.
- Corrosion-resistant chassis: Enclosure Aluminum.
- Heavy-gauge terminal lugs: Electrical Terminals Screw Terminals 35 mm² / AWG 2.
- Drip-proof casing rating: Protection Category IP21.
- Physical mass: Weight 12,5 kg 13,5 kg.
- Cabinet dimensions: Dimensions (h x w x d) 460 x 214 x 110 mm.
Split-Phase 120/240V Balancing Architecture
In North American off-grid installations, 120V household loads are often distributed unevenly across two 120V legs. Connecting an Autotransformer to a 240V European inverter allows the transformer to carry the unbalanced neutral current, keeping leg voltages perfectly symmetrical.
The Victron Autotransformer provides split-phase 120/240V load balancing and step-up/down transformation (Continuous Neutral: 45A @ 40°C | Feed-Through: 50A / 100A, 50/60Hz):
- AC Input / Output: 120 / 240 V Config, 50A / 100A 240V Feed, 35 mm² / AWG 2 Term, 50 / 60 Hz Line.
- Toroidal Balancing: Toroidal Core, 45A Contin. Neut., 55A (30 min Peak), Step-Up / Step-Dn.
- Protection: 2-Pole Breaker, 50A or 100A, IP21 Alum., Ground Relay.
Installation Rules & Electrical Connections
- Supply Connections: Land heavy AC power cables into the Electrical Terminals Screw Terminals 35 mm² / AWG 2 across Input/output Voltage 120 / 240 V and Frequency 50/60Hz.
- Protection Switchgear: Engage the integrated Input Circuit Breaker 50A, Two Pole 100A, Two Pole protecting the Maximum 240 V Feed Through Current 50A 100 A circuit.
- Neutral Current Management: Size neutral conductors to manage **Neutral Current, Continuous 45A @ 40°C/100°F and **Neutral Current, 30 min 55A @ 40°C/100°F.
Toroidal Core Design & Neutral Balancing
The Autotransformer delivers high efficiency and low idle loss:
- Toroidal Magnetic Core: Built around a Transformer Type Toroidal winding for silent operation and low standby power dissipation.
- Aluminum Enclosure: Encased inside an Enclosure Aluminum rated Protection Category IP21, with Weight 12,5 kg 13,5 kg and Dimensions (h x w x d) 460 x 214 x 110 mm.
- Multi-Model Lineup: Available across Autotransformer 50 A 100 A continuous configurations.
Technical Specifications & Sizing Summary
Parameter | Engineering Rating | Design Significance |
|---|---|---|
Model Hierarchy Lineup | Autotransformer 50 A 100 A | Scalable balancing capacities for marine and off-grid systems |
Operating AC Voltage | Input/output Voltage 120 / 240 V | Configurable step-up, step-down, or split-phase balancing |
Primary Circuit Breaker | Input Circuit Breaker 50A, Two Pole 100A, Two Pole | Integrated thermal-magnetic two-pole overcurrent protection |
Operating Frequency | Frequency 50/60Hz | Universal compatibility with 50Hz and 60Hz AC systems |
Max 240V Feed-Through | Maximum 240 V Feed Through Current 50A 100 A | Handles total continuous pass-through power |
Continuous Neutral Current | Neutral Current, Continuous 45A @ 40°C/100°F | Sustained neutral imbalance handling in hot climates |
Peak Neutral Current (30m) | Neutral Current, 30 min 55A @ 40°C/100°F | Handles large temporary single-leg motor starts |
Magnetic Core Technology | Transformer Type Toroidal | Low acoustic hum and high transformation efficiency |
Cabinet Construction | Enclosure Aluminum | Lightweight corrosion-resistant aluminum housing |
Power Screw Terminals | Electrical Terminals Screw Terminals 35 mm² / AWG 2 | Large terminals accommodate heavy copper conductors |
Ingress Category | Protection Category IP21 | Drip-proof indoor equipment room rating |
Net Weight | Weight 12,5 kg 13,5 kg | Heavy-duty commercial transformer build |
Cabinet Dimensions | Dimensions (h x w x d) 460 x 214 x 110 mm | Compact wall-mounted chassis footprint |
Add a battery at a surveyed price
Installers quote supply and fitting of the battery on this page for your existing or new system.
How this pays for the site: installers pay SolarNevs a fixed introduction fee when we pass them a genuine enquiry. They cannot pay to appear higher, and our surveyed prices are published before any introduction. You can also take our dated price tables straight to any installer.
Frequently asked questions
What models and voltage configurations apply to the Victron Autotransformer?
The series includes **Autotransformer 50 A 100 A** operating with **Input/output Voltage 120 / 240 V** across a **Frequency 50/60Hz** line supply (August 2026).
What circuit breaker protection and feed-through current ratings are built in?
It provides **Input Circuit Breaker 50A, Two Pole 100A, Two Pole** and handles a **Maximum 240 V Feed Through Current 50A 100 A** (August 2026).
What neutral current imbalance capacities and physical construction ratings apply?
It delivers **Neutral Current, Continuous 45A @ 40°C/100°F** and **Neutral Current, 30 min 55A @ 40°C/100°F** across operating temperatures using a **Transformer Type Toroidal** core, **Electrical Terminals Screw Terminals 35 mm² / AWG 2**, and an **Enclosure Aluminum** with **Protection Category IP21**, weighing **Weight 12,5 kg 13,5 kg** with **Dimensions (h x w x d) 460 x 214 x 110 mm** (August 2026).
References
- Victron Energy: Autotransformer Manual — accessed 31 August 2026
Related guides
More from what to buy — and how not to get cheated.