48 Volt Revolution?Here’s why in-flight electrical systems are changing

It used to be all about 12, then it went to 24, and now we are increasingly talking about 48 volts for on-board systems. Why? First of all for a reason of weights on board. But not only that.

The starting point, going back as far as the 1990s, is that of a world in which all on-board systems on boats were exclusively 12 volts.
Then it went to 24, now we are starting to talk about 48.
This is the same path that the automotive world has taken, with more than a decade ahead of it(remember “cigarette lighters” in the dashboard?).
The latest big acceleration, in the automotive field, has come with electric and hybrid powertrains, where, with ever-increasing power outputs, the use of 48-volt systems has become a must (and where 400 or 800 volts are also being used).

But in the sailing world, what is the point, really, of making this transition? ”
The first big advantage,” explained
Armando Villa of Green Yacht, which has been working in the sailing world for forty years and in particular deals with everything related to plant engineering and electric propulsion – Is in terms of weight.
Working at 48 volts means being able to drastically reduce the diameter of cables.
Just to give you an idea, you go from 70 mm square ones, which weigh kg/meter, to 35 mm ones that weigh exactly half as much “. Perhaps one would think that these are minimal gains in the end, but that is not the case, especially in the world of racing or even simply the latest generation of performance cruisers, where saving every kilogram is vital. Boats are becoming more and more complex with more sophisticated systems branched throughout the boat. “Just think,” Armando Villa told us again. to the “long way” the wiring has to go on a twenty-meter boat to get all the way to the bow, to the maneuvering propeller, starting in the engine room.
Or to how many electric winches are on board: on a boat that size there are easily six, and all of them have to be cabled.” And the same goes for hydraulics, aft planks, and cockpit tables.
Owners and their crews are used to managing and moving everything on board at the touch of a button .
“Il vantaggio in termini di peso poi non riguarda solo i cavi ma anche le scatole per la loro gestione, i connettori i capicorda.
Alla fine il guadagno per quanto riguarda il peso si fa sentire, e anche dal punto di vista economico.
Inoltre far passare i cavi, compiere il lavoro di installazione, è ovviamente più complesso da gestire se i diametri sono maggiori “.

The question that arises is why do we still see so few 48-volt systems, even on the latest generation of boats…? “The answer is very simple,” Villa further explains. because there are still few accessories in the boating world that work with 48 volts.
It is getting there.
Some big manufacturers like Harken, Bamar, Lewmar are doing it.
The way has been shown, even in the nautical world, by electric and hybrid propulsions where powers that now go up to 20/30 kW must perforce work at 48 volts.
Here you can rely on lithium batteries, in many cases the same ones found in cars, which are 48 volts “. Supplier companies are adapting to this transformation. A good example of the comparison between past and present is among small equipment such as Vhf or shipboard radios that still operate on 12 volts, whereas when very high currents are involved, for example, for winches and winches, the process has already started. “For example,” Villa told us again. On motor yachts, of 18 to 20 m, bow thrusters have long been 48-volt.
The problem arises, as is easy to imagine, on smaller sailboats .” The other fundamental reason why higher voltages are not used at sea, going up to 400 or 800 volts as is the case now with electric cars, is of course safety.
Water is definitely conductive, so in the marine environment it is easier to foresee a short-circuit situation than on the road, which is why safety standards are different.
However, the underlying technologies have definitely evolved, and legislators are considering standards for boating, and in the European Community there is currently talk of raising the limit to 50 volts.
Another fundamental reason why the move to 48 volts in the nautical world would be very useful is that 48-volt battery technology is critical for powering advanced on-board power management features that are becoming more numerous and complex.

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48 volts = smaller cables. Here’s why

It all starts with the formula: Watts = Volts x Amps. The size of the cables is dictated by the amperes the cable carries.
The easiest way to understand it is the analogy with the plumbing world, with batteries being the tank full of water.
Due to the force of gravity, opening the faucet turns the potential energy of the water into kinetic energy: volts (V) identify precisely this potential difference, or voltage.
The flow of water generated when the faucet is opened is the current and is measured in Amps (A), while Watts (W) are the power the water expresses as it leaves the pipe.
A 12-volt system drawing, say, 1,500 watts (e.g., a bow anchor windlass) must carry 125 amperes (1,500 divided by 12).
A 48-volt system producing the same 1,500 Watts would require only 31.2 Amps (1,500 divided by 48).
The diameter of the copper wires required by 31.2 Amps is significantly less than that required by 125.
Wanting instead to move on to talk about the autonomy of a battery, we instead use Ampere Hours (Ah), which, as is easy to guess, indicate the current that can be delivered in one hour, beyond which the battery (our water tank) is considered “empty.”
In practice: a 1,000 Ah battery will maintain a current of 1,000 A for 60 minutes, or 500 for 120 minutes. By Luca Sordelli