What are the sources of electricity on a boat?
Updated on: 26/05/2025On a boat, whether sail or motor, the sources of electricity are as follows:
- Away from port: the boat’s battery bank, which provides 12-volt power. Generally, the bank consists of three batteries: one battery to start the engine and two so-called service batteries, which power the rest of the electrical equipment on board. They recharge when you run the engine. When the engine isn’t running, the key is moderation.
- When you’re docked:shore power, which provides unlimited 220-volt power. Note also that spending a night at the dock is the best way to fully recharge the batteries.
Modern sailboats and motorboats often have a built-ininverter that converts the 12-volt power from the batteries into 220-volt AC power. While sailing or at an anchorage, this allows you to easily plug low-power devices (phones, computers, speakers) into the standard AC outlets on board, but not high-power devices (auxiliary heaters, respiratory assistance), otherwise the batteries will drain too quickly. However, some boats do not have a built-in converter, so it’s best to bring your own cigarette lighter adapter just in case, so you can charge your phones.
Some luxury boats have a generator, allowing them to produce electricity from fuel (note: this is a noisy device, not very pleasant to run at night!).
Our advice: always pack a 12-volt cigarette lighter adapter in your luggage so you can charge your phones while underway, even if the boat doesn’t have a built-in converter.
On river boats or cruising houseboats, you’ll find 12-volt and 220-volt outlets, but the latter will only work if you’re docked. If you’re underway, you’ll only be able to use the 12-volt outlets (cigarette lighter sockets). We recommend bringing cigarette lighter phone chargers with you. However, the rental company can also provide you with a 12/220 V converter as an extra for about ten USD. It’s a small device that allows you to plug in standard plugs (220 V).
