Best Inverter/Charger for Class A, B, and C Motorhomes
Motorhomes are not one category. A Class B campervan, a Class C on a cutaway chassis, and a Class A diesel pusher have almost nothing in common when it comes to electrical systems — different AC loads, different battery bank sizes, different shore power configurations, and completely different physical constraints for where components can live.
The right inverter/charger for each is similarly different. Here's how to think through it by class.
What an Inverter/Charger Does in an RV Context
An inverter/charger combines two functions: inverting (converts DC battery power into 120V AC for household loads) and charging (when shore power or a generator is connected, charges the battery bank, then automatically switches back to battery when AC input drops). For motorhomes, the inverter/charger is the backbone of the entire AC system.
Class B: Campervans and Small Conversion Vans
The constraint: Space and weight. Every cubic inch and pound is accounted for in a Sprinter, Transit, or ProMaster build.
The load profile: Modest. 12V compressor fridge (DC, no inverter needed), laptop charging, lighting, CPAP, and occasional small appliances. Very few Class B owners run a microwave regularly.
Shore power: Usually 30A/120V.
What fits: The Victron MultiPlus-II 12/2000/80 is the standard choice. 2,000VA covers the typical Class B load profile cleanly; 80A charging fills a 200Ah LiFePO4 bank from 20% in about two hours on shore power. For builds with a very light AC load, the MultiPlus-II 12/1200/50 is smaller, lighter, and draws less quiescent power.
Class C: Cutaway Chassis Rigs
The constraint: More space than a Class B, usually a basement compartment or utility area behind the cab.
The load profile: Higher. Residential-style fridge, microwave, coffee maker, TV, CPAP. Peak simultaneous draw can easily reach 2,000–3,000W.
Shore power: Usually 30A/120V; some larger rigs wired for 50A/240V split-phase.
What fits: For a 30A Class C, the Victron MultiPlus-II 12/3000/120 is the standard recommendation — 3,000VA handles simultaneous appliance loads with headroom, and the 120A charging output is efficient for 200–300Ah banks. For 50A split-phase Class C rigs, the Victron MultiPlus-II 2×120V is the correct unit, designed for L1/L2/neutral/ground four-conductor wiring.
Class A: Full-Size Motorhomes
The constraint: Power demand, not space. Class A owners expect to run air conditioning, a full residential kitchen, entertainment systems, and sometimes a washer/dryer simultaneously.
The load profile: High. Peak simultaneous draw can reach 4,000–6,000W+. A/C alone pulls 1,200–1,800W per unit.
Shore power: Almost universally 50A/240V split-phase — two 120V legs at up to 50A each, for 12,000W of available shore power.
What fits: The Victron Quattro 2×120V is the right inverter/charger for most full Class A builds. Designed specifically for 50A split-phase service, up to 8,000VA inverting capacity. For rigs with onboard generators, the Quattro's two AC inputs handle shore power on AC In 1 and generator on AC In 2, managing automatic switching between them — no external transfer switch needed.
Universal Rules — Regardless of Class
- Match the voltage: The unit must match your battery bank voltage (12V, 24V, or 48V). Don't mix them.
- Size for peak AC draw: Microwave + coffee maker + fridge compressor starting simultaneously — that's your inverter sizing number.
- Configure for lithium: Out of the box, Victron units are configured for lead-acid. Reconfigure absorption and float voltages for LiFePO4 using a Victron MK3-USB interface and VEConfigure software.
- AC Out 2 for the air conditioner: Wire the A/C to AC Out 2, which only passes power when shore power or a generator is present. Prevents accidental battery drain while boondocking.
Quick Reference by Class
| Class | Shore Power | Recommended Unit | Battery Bank |
|---|---|---|---|
| Class B | 30A | MultiPlus-II 12/2000/80 | 100–200Ah LiFePO4 |
| Class C (30A) | 30A | MultiPlus-II 12/3000/120 | 200–300Ah LiFePO4 |
| Class C (50A) | 50A | MultiPlus-II 2×120V | 200–300Ah LiFePO4 |
| Class A | 50A | Quattro 2×120V | 400–600Ah LiFePO4 |
Browse the full inverter/charger collection at Blue Marine. If you want help matching the right model to your specific rig, wiring setup, and load profile, schedule a free consultation with our team.
Related reading:
Victron MultiPlus-II Sizing Guide: Which Model Do You Need?
The Complete RV Solar and Battery Upgrade Guide
How to Size a Battery Bank for Your RV: A Practical Guide
