Marine Electronics: Marine Power Inverters

Mastervolt Powercombi

The Mastervolt PowerCombi charges batteries and provides AC current for onboard appliances silently and reliably.

An essential component of any offshore cruising yacht’s electrical system is an inverter, which converts 12V DC into 110V or 220V AC. As much as we might want to create a 12V alternative reality for ourselves offshore and at anchor, reality speaks for itself: we still need AC for many electrical appliances and systems.

Power tools and appliances, including drill motors, small circular saws and blenders, are available in 12V versions, but many yachties still prefer the higher performance of AC tools and fixtures. Fortunately, the range of marine and recreational inverters is wide and varied, from small cigarette lighter adapters all the way up to highly sophisticated, fan-cooled designs offering full sine wave AC current safe enough to support highly sensitive electronic appliances, such as microwave ovens and laser printers.

At the humbler end of the price range for full sine wave inverters is the Renogy 2000W inverter/charger, which offers “cleaner, smoother and more reliable electricity” for all loads in its range requiring a genuine full sine wave power source.

The Renogy 2000W inverter, boasting a much higher current rating than many products in its class, can be used for an assortment of appliances –– such as AC drill motors, circular saws, lights, and electronics –– simultaneously without interference.

Special LED indicators afford protection from excessive voltage ranges, temperature variation and short circuits. Also, high-speed ventilation fans ensure the inverter runs at a safe temperature. In keeping with modern AC electrical practice, the Renogy 2000W includes GFCI protection. And though the Renogy will set you back only about $300, this unit runs quietly, unlike some of its bargain-basement competitors.

In the middle of the inverter price range is The Xantrex Freedom XC Inverter/Charger, which is designed to provide 1000W of “true sine wave AC” for permanently-installed cabin and galley appliances –– such as a microwave, washer and dryer –– flawlessly and quietly. This robust system offers protection in surges of up to double continuous power for two seconds, an important feature for handling electric motor start-up surges occurring when a microwave or fridge compressor starts up.

When in operation with the engine running, a “programmable, configurable, three-stage” charging algorithm ensures optimal charging of most types of batteries ranging up to 18 volts. The Xantrex’s 30A transfer relay senses AC shore current and then transfers the vessel’s electrical load to that source to protect battery charge.

However, when you are using shore power to charge the batteries, this Xantrex inverter-charger actually uses less shore amperage, saving money on marina charges and freeing up current to be used in running onboard appliances, which also provides some assurance against tripping dockside electrical breakers.

At roughly $700, the Xantrex Freedom XC will easily pay for itself many times over when we consider the savings in terms of longer battery life and the protection offered to the vessel’s varied electrical and electronic systems through safe, carefully controlled AC output and battery charging.

For a few more bucks, you can invest in a Mastervolt PowerCombi 12V, 1200W Pure Sine Inverter, 50A Charger, which is in the same class as the Xantrex Freedom XC. Though the PowerCombi operates as a stand-alone inverter/charger, it is designed to be easily integrated, using an additional interface, into a MasterBus network.

The PowerCombi is easy to install and offers a built-in transfer switch for shore power, double surge protection for up to three seconds, and adaptability to charge Li-ion batteries. The unit handles voltage ranging from 10V to 15.5V DC, and, of course, it may be used for flooded, gel, AGM and a variety of custom battery types.

At roughly $800, the Mastervolt PowerCombi is a bit pricier than other units in its class but is backed by more than two decades in the design and manufacture of electronic and electrical gear for marine, off-road and industrial applications.

Your choice of inverter or inverter/charger will provide a major boost to your cruising lifestyle, so select the unit offering the best quality, durability, and ease of use.

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