A Victron RV electrical system replaces the RV’s stock converter and basic inverter with a set of parts that work together: a MultiPlus-II inverter-charger, a SmartSolar MPPT, a battery monitor and usually a Cerbo GX. This guide explains what each part does in an RV, using the MultiPlus-II 2×120 that full-time RVers like Changing Lanes and RV with Tito installed on camera, and the specs Victron publishes.
Electrical work can be dangerous: follow the manual, fuse and size every cable correctly, and use a licensed electrician for anything connected to household wiring.
Victron RV Electrical System: The Parts
| Part | Role in the RV | Official spec highlight |
|---|---|---|
| MultiPlus-II 2x120V | Inverter, charger and transfer switch for 50A rigs | 3000VA / 2,400W continuous at 25°C, 50A per leg input |
| MultiPlus-II 120V | Same for 30A single-leg rigs | 12/3000/120: 120A charger, 50A transfer switch |
| SmartSolar MPPT | Roof solar | 100/50: 700W nominal on 12V |
| SmartShunt or Lynx Shunt | State of charge | SmartShunt: 6.5–70VDC |
| Cerbo GX + GX Touch | One screen, VRM, generator start | Remote monitoring over Wi-Fi or Ethernet |
How the MultiPlus-II 2×120 Handles a 50A RV
From Victron’s datasheet: the 2×120 accepts a split-phase 120/240V supply or a single 120V supply. It charges from L1 only. In inverter mode it ties L1 and L2 together so both sides of the RV panel get 120V. That means 240V loads only work when you are plugged into split-phase power. The L1 output transfers in under 20ms; L2 takes about 40ms.
PowerAssist on Weak Pedestals
Set the input current limit to what the pedestal can supply. PowerControl then reduces charging to stay within it, and PowerAssist adds battery power when your loads exceed it. Victron notes PowerAssist works on the L1 input on the 2×120. On a weak 15A hookup, the battery covers the difference above the input limit until it reaches its low-voltage limit, so plan loads accordingly. That explanation is based on Victron’s description of PowerAssist, not our own test.
Replacing the Stock Converter
Most RV conversions remove or disable the factory converter, since the MultiPlus-II’s charger replaces it. Two things to plan for are GFCI outlets and neutral-ground bonding. The MultiPlus has a ground relay that bonds neutral to ground when inverting, which interacts with the RV’s existing wiring. Have an RV electrician confirm your setup.
Solar and Monitoring
A SmartSolar 100/50 on a 12V bank covers about 700W nominal of roof solar per Victron’s rating. Add a SmartShunt or Lynx Shunt for accurate state of charge, and a Cerbo GX to see everything on one screen and in VRM.
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Parts: Victron MultiPlus-II 12V 3000VA 2×120 on Amazon, Victron SmartShunt 500A on Amazon, Victron Cerbo GX.
Datasheets and manuals for the Victron SmartSolar MPPT 100/50 and Victron GX Touch 50 are on Victron’s website.
Example: A 50A Fifth Wheel Conversion
| Part | Example pick |
|---|---|
| Inverter-charger | MultiPlus-II 12/3000 2×120 |
| Battery | 400Ah 12V lithium |
| Solar | 800W on the roof with a SmartSolar MPPT 150/60 |
| Monitoring | SmartShunt and Cerbo GX with GX Touch 50 |
| Alternator charging (optional) | Orion XS 12/12-50A from the truck |
Example build; size every part for your RV and have an RV electrician check the AC wiring.
Example: A 30A Travel Trailer
A travel trailer with a single 30A inlet uses the standard MultiPlus-II 12/3000/120, a 200–300Ah lithium bank, 400W of solar with a SmartSolar MPPT 100/30 and a SmartShunt. The Cerbo GX is optional, since VictronConnect on a phone shows each device.
Daily Energy in an RV (Estimate)
| Load | Energy per day |
|---|---|
| Residential fridge via inverter | About 1.5kWh |
| Lights, water pump, fans | About 0.4kWh |
| TV, laptop, phones | About 0.5kWh |
| Coffee maker, microwave (short use) | About 0.4kWh |
| Inverter idle | About 0.3kWh |
| Total | About 3.1kWh (about 240Ah at 12.8V) |
Estimates. A 400Ah bank and 800W of solar cover that on most sunny days.
What the Cerbo GX Adds in an RV
The Cerbo GX shows shore power, solar, battery and loads on one screen. Through VRM, you can check the RV while it’s in storage, and its relay can start a compatible generator on low battery. It also passes battery limits to the MultiPlus and MPPT through DVCC.
Choosing the Solar Charge Controller
| Roof array at 12V | Example SmartSolar MPPT |
|---|---|
| Up to about 440W | 100/30 |
| Up to about 700W | 100/50 |
| Up to about 860W | 150/60 |
| Up to about 1,000W | 150/70 or 250/70 |
Nominal PV figures from Victron’s datasheets. Wiring panels in series keeps the current low on the run from roof to controller, which suits the 150V and 250V models.
Commissioning Checklist
- Set the MultiPlus-II battery type, charge voltages and AC input limit.
- Set the MPPT battery settings to match.
- Enter the battery capacity and lithium settings in the SmartShunt.
- Connect everything to the Cerbo GX and turn on DVCC if your battery supports it.
- Test shore power, inverter mode and the transfer between them.
FAQ
Will a MultiPlus-II run my RV air conditioner?
The 12/3000 model is rated 2,400W continuous at 25°C, so many single rooftop units are within range, but compressor start surge matters. See our RV air conditioner guide.
30A or 50A RV: which MultiPlus?
50A split-phase rigs usually use the 2x120V model. 30A single-leg rigs use the standard 120V MultiPlus-II.
Do I still need the RV converter?
Usually not, because the MultiPlus-II charger replaces it.
Can I see my RV batteries remotely?
Yes, with a Cerbo GX connected to the internet and the free VRM portal.
Can I keep the RV’s existing 12V fuse panel?
Usually, yes. The DC fuse panel connects to the battery system through the shunt, just like the other DC loads.
Does the MultiPlus-II 2×120 charge from both legs?
No. Victron’s datasheet says it charges from L1 only.
Sources: Victron datasheets for MultiPlus-II 2x120V, MultiPlus-II 120V, SmartSolar MPPT 100/30 & 100/50 and SmartShunt (victronenergy.com); Changing Lanes, “RV Inverter Upgrade! (Victron Multiplus II 12V 2×120 and CerboGX!)”; RV with Tito DIY, “Installing the Victron Multiplus II Inverter to Power our 50A RV Off-Grid”.
Related: EcoFlow Delta 3 Max RV Boondocking, Can the Delta 3 Max Run an RV Air Conditioner?, BougeRV Arch Pro 200W Flexible Solar Panel Review, plus the Victron Energy Guide