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Marine Lithium & Inverter FAQ: How to Size a Victron Power System

Most high-ticket power upgrades we support start with Victron: inverter/chargers, MPPT solar controllers, and battery monitors on a single monitoring bus. Below are the questions we hear most often before customers order.

How big an inverter/charger do I need?

Add your AC loads (microwave, induction, water heater, chargers) and pick headroom. A 3,000 VA MultiPlus-II 3000 covers many 30–40 ft cruisers; larger liveaboards step up to the 5000 VA 24V or MultiPlus 2000 for simpler coastal boats.

Do I need a battery monitor?

Yes — lithium and mixed banks are hard to manage by voltage alone. The BMV-712 Smart or SmartShunt 500A gives accurate state-of-charge and syncs to VictronConnect.

What solar controller should I pair?

Match controller amperage to panel short-circuit current. Popular picks: SmartSolar 100/30 for modest arrays, 150/70 for larger liveaboard roofs. Use the Victron sizing spreadsheet or ask us with panel specs.

Do I need a Cerbo GX?

For multi-device systems (MultiPlus + MPPT + monitor + tank sensors), the Cerbo GX centralizes data to a single touchscreen or VRM portal. Smaller boats often skip it until they add a second MPPT or generator control.

Can I run lithium with Victron?

MultiPlus-II units support lithium profiles when battery manufacturer settings are programmed. Always confirm BMS compatibility and charge/discharge limits before your first offshore trip.

Shop Victron power systems or request a load list review before checkout.

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