Eletrical System, part 3 – Data network for electrical equipment

Modern electrical components often have the ability to share information via a data network. In this article, you will learn a little more about what possibilities and limitations they have.

This technology has opened up many new opportunities to both see information about, among other things, the charging state of the batteries, and also to control the electrical system in a ”simple” way. Among other things, you can connect flexible displays you program yourself with which information about the electrical system to be displayed on the screen, eg the charge level of the various batteries on a single image. You can also control, for example, starting or stopping the inverter from the programmable display. It is also relatively ”easy” to build electrical systems where you can synchronize the charging of a battery bank with several parallel 3-stage chargers or solar panel regulators in parallel with charging from other energy sources.

Manufacturers and standards

I only know of one manufacturer who has a solution for networking most products for boats’ electrical systems, and that is Mastervolt with its network solution MasterBus.

Another of the major manufacturers in the European market, Victron, has two different network solutions. VE.smart networking and VE.bus. VE.smart establishes a WiFi network that allows sharing of information about battery charging. The solution also allows synchronization of charging with several Victron chargers installed. With VE.bus, which is a cable network, the charging of Lithium batteries is controlled at the cellular level, a so-called BMS, Battery Management System.

The network solution presented in this article is based on MasterBus from Mastervolt.


There is a network standard CAN bus developed by the automotive industry. This standard has been used by Mastervolt to create electrical components that communicate over a computer network.

In addition to the various components of the electrical system (chargers, batteries, chargers, relays, shunts, etc.), you can also connect special display and control equipment, and thus view information and control the components on the network with special programs adapted to the components of the current network.

Type of network

Mastervolt’s network is a so-called serial network. This means that the network passes through each component. They are connected with two network cables and if you disconnect a component, the network path is broken and it stops working.

Termination of network

Each component that connects to the network has two network outlets. The component that sits first or last in the network needs a special connector (network termination) that is inserted into the empty socket. If there is no termination, the network will not work.

Power to the network

The network receives power from one or more of the components that are connected to the network, eg the battery or a charger that is already connected to the electrical system. This way you do not have to connect all network components to the electrical system.

The components that can provide power are stated in the information provided by the manufacturer. Because the computer network connects components in different electrical subsystems, the part of the component that handles the network is galvanically (electrically) separated from the rest of the component so that the network is powered by the same type of electricity regardless of whether the component is connected to 230V AC, 12V, 24V or 48V DC.

The networks have restrictions on how many components can be supplied with power from one place and whether it may be necessary to have several power sources connected at regular intervals in the network.

Interface to other manufacturers

To connect products from other manufacturers in the network, you need to supplement the network with a so-called interface to another type of network standard, eg, WiFi, NMEA2000, or CZone. There may be limitations in these interfaces compared to information and function in the core network.

An interface allows you to connect other products to the network. In order to be able to understand the information sent through the interface, the connected product also needs to be able to interpret and understand the information.

If you connect a WiFi interface to the network, then it is possible to connect with a Smartphone or computer. But to be able to use the information sent via the interface, you need an App or a PC program that understands the language spoken on the network. The language can be MasterBus, NMEA2000, or something else.

Some interfaces do this translation, for example, an interface to an NMEA2000 network, other interfaces continue to talk MasterBus.


Keep in mind that these components can be located in areas where there are a lot of electrical disturbances that can interfere with the Wifi signal.

I recommend that you only use wifi if the component is not crucial for the electrical system to work. If you want to connect a component to see eg battery charging, then it is OK with WiFi. If, on the other hand, the component is to control and disconnect the alternator, use a network cable for the connection.

Network drawing for the boat

This drawing shows the components that are connected to the NMEA network of the electrical system. All components are connected with network cables.

This drawing should show the order in which the components are connected. This makes it easier to troubleshoot the network and to make changes to the electrical system.

Because the components have the same provider, they can be connected in the same network and understand each other’s information. This allows a battery to tell a relay to open or close the switch that is the case with C, D and F in the picture.

Contacts C, D, and F are the same contacts as in the drawings of the electrical system earlier in the article.

In our case, the network receives power from both LiFePo4 batteries (indicated by the flash symbol at the network connection).

NOTE! The USB port and Ctrl Panel are two components that receive power via the network and therefore do not need to be connected to any of the electrical subsystems. These components are therefore not included in the standard electrical drawing.

Configuration of the electrical components

Many of the electrical components that are connected to the data network may need special settings, such as setting whether a charger charges an AGM or a LiFePO4 battery, which shunt is connected to the AGM battery, and so on.

Some components also have the option to set what should happen when a special event occurs, for example when the LiFePo4 battery bank is fully charged. Then a signal must be sent to the connector C to cut off the electric current from the generator.

This configuration of the electrical components is done from a program on a PC connected to the USB interface in the computer network. From the program, you can see information about all electrical components connected to the network. The components can report voltage, current, etc. at the various points where they are connected and this makes it easy to see eg abnormal voltage drops in the system.

These settings must be made by someone with good knowledge of how the electrical system and components work. If it goes wrong, the electrical system can stop working and it can also happen that something breaks, for example, a charger with the wrong charging parameters can quickly destroy a battery.

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