Marine Electric Systems designs and installs marine inverter/chargers for sailing yachts, catamarans, and motor yachts throughout the Chesapeake — Annapolis, Baltimore, and the greater Washington DC area. An inverter/charger is the AC heart of a modern marine electrical system, converting battery power to 120V or 120/240V AC for onboard loads while charging the battery bank from shore power or the generator. Done right, it's a single intelligent unit that integrates cleanly with your lithium house bank, alternator, and Cerbo GX monitoring — not a parallel patchwork of inverters, chargers, and combiners that don't talk to each other.

What's included in a marine inverter/charger install

• Inverter/charger sized to your boat — Victron MultiPlus 12V/24V (1200W to 5000W) or Quattro (3000W to 15000W with two AC inputs)
• Brand-agnostic specification — Victron Energy, Mastervolt, and others; we recommend the right unit for your boat, electrical demands, and budget
• Auto Transformer for 120/240V split-phase — automatic load balancing across the 240V supply, preventing leg imbalance from tripping the main breaker
• Length-matched 4/0 AWG positive and negative cabling — Class-T fuses on the DC side, breaker-protected AC input and output
• Charge profile programmed to your battery chemistry — LiFePO₄, AGM, or flooded lead-acid; firmware updated at commissioning
• Cerbo GX integration — VE.Bus communications so the inverter/charger reports into the unified system monitoring
• AC current-limiting — to protect 30A, 50A, or 100A shore connections during heavy charging
• Power-assist functionality — Victron units can boost shore power from the battery bank, letting you run heavier loads than the shore inlet alone supports
• ABYC-compliant installation — proper cable sizing, fuse and breaker protection, and bonding
• As-built documentation — AC and DC schematics, full system test, and an owner walkthrough

Why a modern inverter/charger matters

Older split inverter-and-separate-charger setups (and dated all-in-one units from the Magnum era) work, but they don't integrate. They can't be programmed for LiFePO₄ charge profiles. They can't communicate with a Cerbo GX. They can't automatically transfer between shore, generator, and battery without quirks. And they don't have the surge capacity that lithium banks make possible. A modern Victron MultiPlus or Quattro changes all of that. You get pure sine wave output, programmable charge curves, automatic AC transfer, integrated power assist, and full participation in a unified system communications network — so the inverter/charger and every other charge source on the boat work as one coherent platform.

MultiPlus vs Quattro — what fits your boat

Victron MultiPlus is the right choice for most monohull cruising boats up to about 50 feet. A single AC input handles shore power, with internal transfer to inverter mode when shore is disconnected. Models from 1200W to 5000W cover small auxiliary inverters up through full house-load capability on a 30A shore connection. We typically pair MultiPlus 3000W with house banks from 400 Ah to 1,000 Ah of LiFePO₄.

Victron Quattro is the right choice for boats with both shore power and a generator, larger catamarans, and any yacht where redundancy and seamless AC source switching matter. Two AC inputs let you wire shore and generator separately; the Quattro automatically prioritises and transfers between them. Models from 3000W to 15000W, with parallel and three-phase configurations possible. We've installed dual 5000W Quattros in parallel for 10 kW total inverter capacity on cruising catamarans where the demand justifies it.

Brands we install

We are brand-agnostic on inverter/charger selection. Most installs use Victron Energy MultiPlus or Quattro because of how cleanly they integrate with the rest of the Victron ecosystem (Cerbo GX, MPPT, Smart Shunt, DC-DC chargers) — but we also install Mastervolt and other major marine brands when the boat's existing system or owner preference calls for it.

Recent inverter/charger projects

Inverter/chargers are part of every full electrical refit we do. Recent examples on the Chesapeake:

• Dufour 50 — Victron MultiPlus 3000W on a 920 Ah lithium house bank
• Beneteau Oceanis 45 — Victron Quattro 5000W with Auto Transformer for 120/240V split-phase
• Leopard 48 catamaran Tortuga — dual Victron Quattro 5000W in parallel for 10 kW total inverter capacity, with 100A Auto Transformer

For more on how these inverter/chargers integrate with a full lithium platform, see our marine lithium battery installation page.

Service area

Marine Electric Systems serves cruising sailboats, motor yachts, and catamarans throughout the Chesapeake region: Annapolis, Baltimore, the Eastern Shore, the greater Washington DC area, and the surrounding Maryland and Northern Virginia waterfront. We work at marinas, boatyards, and private docks across the region.

Frequently asked questions

What size inverter/charger does my boat need?

The right size depends on what you want to run from battery and for how long. A 3000W unit comfortably runs galley, refrigeration, electronics, and most household-style loads short of resistive heating. A 5000W unit handles a watermaker, induction cooktop, or air conditioning intermittently. Dual 5000W in parallel (10 kW total) is appropriate for catamarans and large motor yachts running multiple AC systems simultaneously.

Can I keep my old charger and just add an inverter?

Technically yes, but it's almost never the right answer. Two separate units cost more than a combined inverter/charger, take more space, can't share charge profiles, and don't integrate with modern monitoring. A single Victron MultiPlus or Quattro is cleaner, more capable, and integrates properly with a Cerbo GX network.

Do I need an Auto Transformer?

If your boat has 120/240V split-phase AC (most US boats over 35 feet with electric water heaters, dryers, or air conditioning), yes — the Auto Transformer balances 120V loads across the 240V supply automatically. Without it, an unbalanced load on one leg can trip the main breaker even when total draw is well within limits.

How long does an inverter/charger install take?

A standalone inverter/charger swap is typically 1 to 3 days. As part of a full electrical refit with new lithium bank, alternator regulation, and DC distribution, the inverter/charger work is integrated into the wider 1 to 3 week refit timeline.

Will it work with my existing batteries?

Yes — Victron MultiPlus and Quattro are programmable for LiFePO₄, AGM, and flooded lead-acid. We program the charge profile to match your specific battery chemistry at commissioning. If the existing batteries are due for replacement, we'll scope that as part of the project.

Get in touch

If you're considering an inverter/charger upgrade or a full electrical refit on a sailboat, motor yacht, or catamaran in the Annapolis, Baltimore, or Washington DC area, get in touch. We'd be happy to scope the project, walk you through what's involved, and recommend the right unit for your boat and how you cruise.