Xantrex Freedom SW3012 12V 3000W Marine Inverter/Charger

The Xantrex Freedom SW3012 is the 12V inverter / charger for boats and RVs that run more than just lights and a fridge. 3000 watts continuous of pure sine wave AC output. 6000 watts peak for the kind of motor-start surge a marine air conditioner or a microwave throws at the system. A built-in 150-amp 12V battery charger that's good enough to keep up with a serious house bank between shore-power sessions. And the marine compliance package (UL458 with marine supplement, CSA, ABYC, FCC Class B) that lets a competent surveyor sign off on the install without a lot of head-scratching.

Pure sine wave matters more than people realize. Modified sine wave inverters power simple loads fine, but they make sensitive electronics misbehave. Modern variable-speed compressors, induction cooktops, electronic motor controllers, lithium battery management systems, modern medical equipment, and high-end audio gear all want clean sine wave power. Modified sine works, until it doesn't, and when it doesn't you usually find out by smelling melted electronics. Pure sine just works.

The 150-amp charger is the part most boaters underrate when they shop inverters. A 3000-watt inverter on a 12V system is pulling 250+ amps from the battery bank under full load, which means recovering that draw quickly when shore power comes back matters. The Freedom SW3012 charger is power-factor-corrected, multi-stage, and temperature-compensated through the included Battery Temperature Sensor. It supports flooded lead-acid, gel, AGM, and LiFePO4 lithium chemistries, with profile selection for each. Lithium support is the right call for current and future house bank technology.

Generator Support Mode is the feature that justifies the upcharge over cheaper inverter/chargers. When you're running off a generator and the AC load briefly exceeds what the generator can deliver, the Freedom SW jumps in from the battery bank and supplements the generator output for as long as needed. No tripping the generator breaker. No coffee maker shutting down because someone started the microwave. The system silently fills the gap. For boaters running smaller generators paired with bigger AC loads, this is a game-changer.

Parallel and series stacking is the second feature that justifies it. Need 6000 watts of continuous AC? Parallel-stack two SW3012 units. Need 120/240V split-phase output for a US-style residential AC system on a larger boat or motor coach? Series-stack two units with the optional stacking cable. The system is designed to grow with the application instead of being a sealed box that you outgrow.

The built-in transfer switch is what makes this an inverter / charger and not just an inverter. When shore or generator power is present, the system passes that power through to your AC loads and uses any excess to charge the batteries. When shore power drops, the transfer switch flips over to inverter mode in less than 20 milliseconds. Connected loads almost can't tell. Modern computers, TVs, and audio gear keep running through the transition. Older mechanical relay-based systems with longer transfer times caused brownout-induced reboots on sensitive equipment.

Xanbus is the Xantrex network protocol that lets the SW3012 talk to the optional Freedom SW Combox. Add the Combox and you get data logs, remote on/off, fault diagnostics, and full system control via your phone or tablet over WiFi. For a liveaboard or a long-distance cruiser, that level of visibility into the power system is the difference between knowing what's happening and guessing.

For installs in commercial fishing, recreational marine, RV, construction, and military mobile applications, the SW3012's wide operating temperature range (-4F to +140F) and conformal-coated circuit boards handle conditions that kill less-protected inverters. Salt air, humidity, vibration, and temperature swings are all in the design spec.

Protection. Battery over-voltage and under-voltage protection (won't drain a bank below safe SOC). Over-temperature shutdown. Automatic overload protection with auto-recovery. Short-circuit protection. Integrated resettable AC breakers on the output. Ignition lockout (when paired with the optional remote panel) prevents the unit from drawing battery power when the alternator isn't charging.

Install. The unit is 15.25 inches long by 13.5 inches wide by 7.75 inches tall and weighs 70 pounds shipping. Mount in a ventilated battery or equipment compartment with proper clearance for the cooling fans. DC connections are 5/16-18 studs requiring 2/0 AWG or larger battery cables for full-load 3000W operation, with proper fusing at the battery end. Plan a Class T or ANL fuse rated 400 to 500 amps for the bank-side fuse. AC connections are dual input / dual output for the 3000W model, which lets you feed two AC source inputs (shore + generator) and two AC load distribution circuits independently.

What's in the box. The Freedom SW 3000 unit, Battery Temperature Sensor, DC terminal covers (red and black) with two sets of #6-32 screws, two Xanbus network terminators, two sets of 5/16-18 nuts and washers for the DC terminals, and the owner's and installation guides. Battery cables, fusing, and AC distribution wiring are not included. Spec those to your install.

2-year limited warranty. Same-day shipping before 3 PM ET on in-stock units.