Desalinator Power Options

There are three major methods used to power watermakers - AC voltage, DC voltage, and engine drive. Each has advantages and disadvantages, and your choice should be made based on how your boat's systems are designed and equipped.

I know there are more options out there, such as hand-crank and towed systems, but these are not practical for most cruising boaters. For anything beyond basic survival, these systems offer no advantages.

AC Voltage Power

AC (alternating current) voltage, usually 110-120 or 220-240 volts, has the advantage of being readily available in almost limitless supply when tied to a dock. However, if your boat is tied to a dock, you likely don't need to run your desalinator. For those yachts equipped with an AC generator (genset), this type of power for your watermaker may be a good choice. Most water maker manufacturers offer AC-powered models with a high output capacity, which reduces the amount of time the unit needs to run. If you choose this power option, try to select a desalinator that will produce all the water you need without increasing your generator running time. AC-powered watermakers are available in modular and fully self-contained designs.

Powering an AC-powered desalinator with an inverter is not a very efficient use of power on board your boat. This is listed as an advantage only because in the event of a malfunction with your generator, you can still produce water if your boat has in inverter. It is always good to have a backup.

DC Voltage Power

DC (direct current) voltage is available aboard nearly every boat that has an engine, and even some that don't. The voltage available depends on your boat's electrical system - most boats have a 12 volt DC electrical system, while some larger boats have 24 volt or higher DC electrical systems. DC-powered desalinators are limited in capacity because of the power required to run the high-pressure pump. For this reason, DC watermakers are usually smaller than 400 gallons per day (16.6 GPH). DC-powered watermakers are available in modular and fully self-contained designs.

Engine Drive

Engine-driven watermakers are designed to be powered by your main or auxiliary engine, through a v-belt. These types of desalinators require very little electric current to operate, and only slightly increase the fuel consumption of the engine while the water maker is operating. If you run your main engine regularly, this may be a good choice. One major consideration when choosing an engine-driven desalinator is the pump speed. All high-pressure pumps have a limit to how fast they can run, and product water quality varies considerably with changing pump speeds. Design your system based on operating the watermaker only when charging batteries at anchor, or while cruising at a steady speed. This style of desalinator is only available in modular configuration. Select a desalinator that will produce all the water you need without increasing your engine running time.