Here’s how marine alternators differ from the ones in your car – Jalopnik

One of the critical components of a vehicle’s electrical system is the alternator. In a car, for example, the energy that powers things like the audio system, climate control and headlights is taken from the alternator while driving. The alternator also ensures that the battery remains charged, allowing you to start the engine.

A boat engine also has an alternator that performs many of the same functions. However, it is not the same as what is under the hood of your car. And these differences are not limited to the alternator, as marine and car engines have many differences. Powering a personal watercraft requires a different approach than driving a car because the environments and conditions present different challenges.

Although they can perform a similar function, marine alternators are built to meet higher demands than those of a car, are made of materials that are corrosion resistant, require more robust cooling, and must include additional safety features.

However, this energy requirement still pales in comparison to that of many personal watercraft. A ship could also be filled to the brim with the latest technology. In addition to the navigation system and lights, a boat may have a battery bank, radio equipment, pumps and more, with an alternator working to support the batteries. While a car alternator can generally generate 40 to 120 amps, a marine version will produce 300 amps.

Larger ships may even have appliances like refrigerators and stoves, as well as other modern amenities, making them comparable to a luxury home. Take for example this retired Dutch Navy ship, reborn as a $24 million yacht, which comes with a hot tub and a humidity-controlled cigar room. Suffice it to say that your car’s alternator is not up to the task of supporting a boat as it would not be able to replenish the starter battery quickly enough, let alone support additional household batteries.

Your car’s alternator is also protected from getting wet and works in a dry environment. A marine alternator must be made of, for example, stainless steel and coated with robust anti-corrosion layers to prevent rust formation.

Under the hood of a car, the heat from the alternator is often managed with multiple fans. However, a marine inboard engine is sealed in a compartment in the ship, so air cooling does not work very well. A marine alternator can therefore be equipped with multiple fans and with significant heat sinks to control the temperature.

The confined environment of an engine room is not only problematic in terms of cooling, but also contributes to potentially dangerous situations. To prevent fires or worse, U.S. Coast Guard safety standards require marine alternators to have something called a spark screen or spark arrestor. This mesh will stop any sparks from the part so that it does not become a source of ignition for flammable gas.