Dual Inverter RV System? Here’s Why You Might Want an Autoformer:

When people start upgrading their RV electrical systems—especially when stepping into the world of dual inverters, full-time boondocking, or large solar arrays—there comes a moment where the equipment they’ve added still doesn’t quite deliver the seamless experience they expected. You may have the battery bank, the solar, the inverters, and the monitoring dialed in, yet a single stubborn question remains:

“Why am I overloading one inverter when I have two?”

This is where the Victron autotransformer (often casually called the “autoformer”) steps into the picture. And for RV owners building 50-amp off-grid systems, understanding how this piece of equipment works can make the difference between smooth sailing and frustrating power limitations.

The Problem: Uneven Power Draw on a 50-Amp RV

A 50-amp RV has two hot legs—L1 and L2. When you install a dual-inverter setup, each inverter typically powers one leg. Under ideal conditions, the loads inside your RV would fall nicely between the two legs. But real RV life rarely works that way.

You may find, for example, that your air conditioner and your microwave both sit on the same leg. If each inverter is rated at 2,400 watts (or even 3,000–4,000 watts), it doesn’t matter how beefy the second inverter is—the first inverter is the one doing all the work while the other loafs around.

That uneven pull can lead to:

• Overloads

• Inverter shutdowns

• Poor performance over time

• A limited ability to run multiple appliances

So, even though you technically have enough power between the two inverters, the RV doesn’t naturally distribute loads in a way that uses both.

The Solution: What a Victron Autotransformer Actually Does

The autotransformer changes everything by allowing both inverters to share the load—even when your appliances sit on the same leg.

Instead of one inverter being hammered while the other sits idle, the autotransformer pulls power equally from both.

For example:

• Air conditioner = 1,700 watts

• Microwave = 1,500 watts

• Total = ~3,200 watts

If these happen to fall on the same leg, the autotransformer automatically balances the load:

• 1,600 watts from Inverter A

• 1,600 watts from Inverter B

No overload. No overheating. No shutting down the air conditioner on a 100-degree day.

This even pull protects your equipment, extends inverter life, and provides a much smoother, “whole-house” power experience.

Why RV Owners Choose an Autotransformer in Larger Solar Systems

As more RVers move to full solar and lithium systems, load balancing becomes a central part of system design. The Victron autotransformer is not about adding more watts—it’s about using what you already have more intelligently.

RV owners usually add one for:

• Large 50-amp coaches

• Dual-inverter installations

• High-demand appliances (AC units, convection ovens, induction cooktops)

• Reducing strain on expensive inverter/chargers

• Tight boondocking setups where every watt counts

If your RV lifestyle has evolved past “bare-minimum power” and into a true off-grid setup, the autotransformer quickly becomes one of those pieces you wonder how you ever lived without.

Do You Need One? A Quick Rule of Thumb

If you have:

• A single inverter → probably not

• A dual inverter system → very likely

• A 50-amp RV → almost certainly

• Appliances that tend to stack on one leg → absolutely

The autotransformer is not a gimmick. It’s a practical fix for a real electrical imbalance.

Where to Get Guidance Before You Build Your System

A Victron-based solar and inverter setup isn’t something you want to guess your way through. Every RV is different, and every layout creates different challenges. That’s why Big Beard Battery created a free solar design form where you can work directly with a certified solar designer who knows Victron systems inside and out.

Whether you’re trying to figure out if you need an autotransformer or you’re planning an entire off-grid build, the design team can map out exactly what you need.

You can start here: BigBeardBattery.com.

Or email the team directly at sales@bigbeardbattery.com for one-on-one help.