A little patriotism! It was the Frenchman Gaston Planté who in 1859 invented the first rechargeable battery system. He managed to store electricity. It is to him that we owe our on-board electrical autonomy!
Start-up or easement?
On a boat you need a battery to start your engine and a battery (or several) for all the electrical consumers on board (navigation electronics, fridge, lighting...). The battery for the engine must be able to deliver high power for a short time (engine starting phase). For the electrical consumers, on the other hand, it is a question of delivering a low intensity, but for a long time. Thus for the first, we speak of starter batteries, and for the second of service batteries. And for each use, different technologies meet the needs.
There are two main families of batteries on our boats.
The family of lead acid batteries
A lead acid battery is a closed, reversible (dischargeable and rechargeable) electrochemical system. In a lead acid battery, two separate electrodes are immersed in an electrolyte liquid.
Each element consists of at least two plates of lead and lead oxide (actually an alloy) constituting the positive and negative poles.
The electrode/electrolyte redox couple generates a flow of electrons through the separator creating a direct current between the poles of each element. In practice each element provides a voltage of 2.1v.
As a result, 12V batteries contain 6 cells of 2.1V, the 24V 12 cells and the 48V 24 cells.
There are several types of lead acid batteries.
- Open lead batteries
- Closed lead batteries
- AGM (Absorbed Glass Matt) absorbed electrolyte batteries
- Gelled electrolyte batteries (Gel)
The lithium battery family
Lithium batteries most frequently used in boating are of the LiFePO4 type. They have the great advantage of having a very stable cathode that does not give off any oxygen (occasionally oxidizing Lithium fires that sometimes occur with other families of Lithium batteries).
Much lighter, they are often used on racing yachts where weight is important. Due to their very high price, they are difficult to find their place on cruising boats. However, their characteristics and in particular their deep discharge capacity make them a magnificent tool for the servitude park.