The anchor windlass, stereo system, echo sounder, air conditioner, navigation lights, refrigerator, outlets for charging smartphones and tablets: year after year, boats are becoming increasingly demanding in terms of electrical energy. And we’re not just talking about yachts; even small and medium-sized boats now host a significant number of electronic devices that require substantial amounts of energy to function. As a result, it becomes increasingly difficult – especially for long trips, cruises, or crossings – to have sufficient energy autonomy. And yes, there are aids, such as photovoltaic panels, but they can’t work miracles. And indeed, when mooring in a marina like our Genoa marina, it’s possible to take advantage of the electrical power pedestals. But obviously, you can’t always stay moored! For this reason, those who travel on small or medium-sized boats often face a dilemma: how to meet the significant energy needs of their boat without facing exorbitant costs and space issues? The solution could be a portable boat generator, knowing that many hulls cannot accommodate a power generator unit.

Difference between inverter and generator

Before looking at the factors to consider when choosing a portable generator for a boat, it’s important to understand what we’re talking about when referring to a generator. It’s therefore useful to highlight the difference between this device and an inverter. The generator is a real engine, a propulsion unit that works at a low RPM specifically to create electrical energy, thanks to its integration with an alternator, which has the role of delivering 220 Volt energy.

Then there’s the inverter, which is not an engine: it’s a device that integrates with the boat’s electrical system and uses the energy contained in the onboard batteries, transforming the voltage from 12/24 Volts to the desired 220 Volts. It can be said that the inverter “transforms” electricity, while the generator “creates” it.

Advantages and disadvantages of the generator

Having understood what a generator is, we can look at the pros and cons of this device, even better in relation to the peculiarities of an inverter. While the latter is compact and takes up little space, and therefore easy to install, the classic generator is heavy and rather large. The generator has the advantage of being able to continue delivering electrical energy potentially without limits, while the inverter, as seen, is conditioned by the capacity of the boat’s batteries. However, it should be said that the generator is noisy and costs more.

But it doesn’t have to be this way: there are generators that take up little space, cost less, and are not excessively noisy, making them suitable for use on boats under 10 meters in length. We are obviously talking about portable generators: let’s now see how to choose the most suitable one for your boat.

How to choose a portable generator for a boat?

It should be immediately clarified that the portable generator is the result of a compromise. It cannot be used improperly, as if one could boast a power generator unit on board: it is still a device of reduced power, which serves to “lend a hand,” but not to solve every type of electrical problem. That said, let’s look at the factors to consider when choosing a portable and compact generator for your boat.

Weight and size: let’s start here, which is essentially the size of the generator. Of course, as this data increases, the power output of the device increases proportionally. But when it comes to boats, every centimeter and every kilogram can make a big difference. It should also be remembered that the weight could be excessive not only for the hull but also for those who will have to move it from the latter to the dock, and vice versa. And certainly, portable generators are often equipped with wheels, but these can often prove completely useless in the passage between the dock and the boat. When reflecting on weight and size, it is therefore important to consider both the space on board and the handling of the device.

Cost: obviously, the cost factor also comes into play when choosing a portable generator for boats. What is the budget we are willing to allocate to have extra electricity on demand on the boat, even when we are far from the moorings of a marina? It should be said that, fortunately, there are models so different even from the price point of view that there are portable generators for boats for all budgets. There are extremely economical models, very simple, that can be purchased for less than 200 or even 100 euros: however, these will be two-stroke generators, to be used only occasionally, and never intensively. And then there are more expensive marine generators, which can exceed – and by quite a bit – 1,000 euros: these are four-stroke devices, equipped with inverters, and designed for regular and continuous use.

Energy requirements: obviously, when choosing a portable generator for your boat, it’s important to consider your actual energy needs. The risk, in trying to save money, is to purchase an engine that can only satisfy a tiny fraction of our needs. How to do it? Simple, it’s good to examine the electronic devices we want to use, estimating for each one the energy requirement, which should be remembered is expressed in Watts; for example, if we have two devices on board that consume 500 W, and if we want to use them simultaneously, we should be able to count on 1000 W. Then we need to relate this figure to our battery bank, and thus understand what generator we need!

Noise: finally, the noise level of the device should be evaluated. There are no completely silent generators; however, there are devices with an electronic regulation system that, by modulating the speed of the propulsion unit, allow for reducing the noise of the generator when possible.