Our MultiPlus vs Quattro overview answers the quick question — this article is for the rigs where the answer was "Quattro": Class A motorhomes, big fifth wheels, and toy haulers running a generator alongside shore power.
Dual AC Inputs, Properly Explained
The Quattro has two AC inputs with automatic priority. AC-in-1 is typically the generator, AC-in-2 shore power (priority is configurable). When you plug into a pedestal, the Quattro transfers to shore power seamlessly; fire up the generator and it switches over without you touching anything — no external transfer switch, no relay box, no "why is nothing working" moment at 11pm. On the Quattro-II 2x120V, the unit also handles US split-phase pedestals, passing both legs through so your 50A service works the way it should.
PowerAssist at Scale
Every Quattro does what makes Victron inverter/chargers special: PowerAssist. Plugged into a weak 30A pedestal but the AC, water heater, and microwave all running? The Quattro adds inverter power from the batteries on top of the shore supply instead of tripping the pedestal breaker — then quietly recharges when the load drops. On big rigs with two air conditioners, this single feature is why owners upgrade.
Sizing the Range
- Quattro 5000VA (12V or 24V): the standard big-fifth-wheel unit — runs one AC plus the residential fridge and outlets.
- Quattro 8000–10000VA (48V): Class A / full-residential territory — two ACs, induction cooking, washer-dryer. At this size, a 48V battery architecture keeps cable sizes sane.
- Stacking: Quattros parallel up to three units and configure for split-phase — the path to genuinely house-scale RV power.
Quattro vs Two MultiPlus Units
A pair of stacked MultiPlus-IIs can also make split-phase power for less money — but you'll still need external generator transfer switching, and commissioning parallel systems is a step up in complexity. The Quattro keeps the system simpler: one box, two inputs, done. Simplicity is worth real money in a vehicle that vibrates down the highway.
The Supporting Cast
A Quattro install wants: a Cerbo GX (monitoring and generator auto-start), a properly sized lithium bank (400Ah+ at 12/24V, or a 48V bank on the big units), Lynx DC distribution with correct fusing, and solar through SmartSolar MPPTs so the generator becomes the backup, not the plan.
Browse Quattro and Quattro-II units in our Inverter/Chargers collection and the full Victron Energy range — shipping from Upland, CA. Big-rig systems reward good design: send us your appliance list and generator size and we'll spec the whole chain.