On-board Power for Sailing Yachts Supplied by Fischer Panda
Hardly any sailor today would want to on board his yacht without electricity. As soon as the shore power socket has been disconnected and the harbour left, the question of on-board power supply arises. On-board power is not only for comfort – safety is also of importance: autopilot, navigation, radio and position lights need a continuous power supply which is usually supplied by the battery bank.
Where does my electricity come from?
Most sailing yachts larger than 14 feet have a built-in engine for safe manoeuvring within the harbour or when there is no wind. An alternator on the main engine charges the battery bank while the engine is running, however, this is only suitable to a limited extent. The main engine generates noise and the load is very low in relation to the engine’s capability due to the alternator’s low power. This results in unnecessary engine wear and tear and high fuel consumption. Exhaust emissions are another important factor.
This charging method is often supported by other sources solar or wind energy, allowing smaller consumers such as a laptop or cabin lights to be supplied with electricity.
Particularly in the tropics, some sort of refrigeration on board is required to cool food and beverages. An additional compressor can be driven by the main engine, although this also has the same negative effects on the engine concerning fuel consumption and the noise on board if the vessel is not using the engine to cruise.
For more comfort
Many owners want to enjoy the same comforts aboard as they do at home. Many are surprised that after dropping anchor in the bay, the air conditioning turns off after an hour of operation. Then it becomes clear that the existing power source is not sufficient.
If larger consumers are to be operated on board or no port is visited for a longer period of time, alternatives are needed.
For an induction stove, TV set, heating and air conditioning either a larger battery bank is required or another reliable power source, e.g. a diesel generator must be installed.
Generators for Individual Power Requirements
The total consumption should never be underestimated. Even small boats have over 60 individual different circuits that need to be taken into consideration. When selecting the on-board power system, we recommend establishing which and how many on-board power consumers (230 V or 400 V) or 12 V or 24 V will be operated.
The selection of the appropriate power generator depends on many factors:
- Size of the yacht
- Number of electrical consumers
- Climate conditions
- Period without shore power
- Duration of use (ALL connected consumers)
Especially air conditioning systems, compressors and pumps and their starting currents require thorough consideration. The Energy Balance provides clarity. From this, the size of the battery bank and the power of the required generator can be determined.
Basically, two types of generators are used - the battery charging generator (DC) or the alternating current generator (AC).
Battery Charging Generator (DC)
If there are only a few 230V consumers on board or if they are only operated from time to time, the battery charging generator is an option. The consumers are supplied via an inverter, which generates the alternating current (230 V AC).
The DC generator is driven by much smaller diesel engine than the ship’s main engine. and charges the battery bank efficiently up to 93 %. The battery charging generator has a very high charging current and running times of approx. 40 to 60 minutes per day are enough to have 24 hours of power on board.
The generator can be started automatically ensuring that there is always enough power on board. In addition, this prevents the battery levels becoming too low and protects them against a deep discharge, especially with continuously operated units such as a refrigerator or an autopilot.
If the generator is normally used less than 50 %, this on-board power concept with battery charging generator is a worthwhile option.
The Classic Option - Alternating Current (AC) Generator
The alternating current AC generator supplies power directly to large electrical consumers on board permanently. Until the 2000s, this generator was only available with constant or regulated speed. The power consumption on board had to be calculated very precisely before the generator was purchased in order to operate the generator optimally (light load problem).
Fischer Panda xGenerator with Constant, Regulated Speed
We recommend an AC generator when a continuous power demand and high starting capacity with stable voltage is required, e.g. when operating an air conditioning system or a diving compressor.
The electrical winding is water-cooled, it produces a perfect sine wave and does not contain any diodes or brushes.
This generator is the optimal solution for price-conscious customers. It is also very reliable and very well suited for use in areas with high ambient temperatures.
The latest version is equipped with a powerful and customer-friendly "xControl" generator control system. It consists of three main components, which are coupled by quick plug connections. These are the digital panel, a transfer box on the generator and the actual control unit. Intelligent communication between these three system components ensures a reliable operation of the generator.
The operator can choose between several languages on the remote control panel and receives current status information of the generator at any time. With an optional communication interface, these messages can also be easily transferred to another information system on the yacht using the SAE J1939 protocol.
In the event of a fault or maintenance, further settings can be made in the service menu. Both the remote control panel and all other peripheral devices such as fuel pump, emergency stop switch, additional pumps or switches and other remote control panels can be easily connected to the generator.
Fischer Panda Inverter-Generator with Variable Speed
Low Fuel Consumption – High Efficiency
Thanks to a modern diesel engine with variable speed, this generator is the optimal solution for varying power requirements on board.
If the power demand is changing, an inverter generator can offer remarkable fuel savings compared to the conventional fixed speed generator. The inverter supplies the electrical load with a constant output voltage; the speed of the diesel engine can be regulated according to the requirements of the consumers that are switched on. As a result, the engine always runs in the optimum power range and requires less fuel. Another cost advantage is that a variable service interval can be set for maintenance as in the automobile sector. This be done via the display panel.
In a test with a Panda 60i PMS marine generator (rated output: 48 kW), a fuel saving of 30% was measured compared to an equivalent fixed speed generator at 20% of the rated load. Even in case of a power requirement of 30 kW, which is 62.5 % of the nominal power, the fuel saving was 10 %.
With its innovative and environmentally friendly inverter technology, the inverter generator offers a very good voltage and frequency stability. This makes it particularly suitable for sensitive electronics.
The light load problem does not arise with variable speed technology. In the case of fixed speed generators, a base load is required in many cases, especially from an output of 50 kW. If the power demand is too low, a load (dummy load) must be connected. This is can be avoided with inverter generators.
Fischer Panda inverter generators with variable speed are currently available in the power range from 4 kW to 48 kW.
Parallel and Multiple Connections of Fischer Panda Generators
The parallel or multiple connection is particularly suitable for multi-hull boats, as it allows an optimum weight distribution.
The power on board can be combined or switched from one generator to another.
It is even possible to connect several inverter generators of different sizes with the help of special parallel inverters. This ensures maximum safety and redundancy.
If required, three inverter generators can be connected. During the day, when the demand is very high, for example, 2 x 20 kW generators can operate in parallel. At night, a smaller 5 kW generator when the power demand is very low. This ensures a constant power supply on board at all times.
The generators are directly connected to each other and do not require an additional parallel control cabinet.
Which Features Must a Modern Generator Have?
Soundproof, Water-cooled, Small, Light, Quiet
Sound Insulation Capsule
Comfort on board also means the least possible noise. Fischer Panda generators are always supplied in a GRP sound insulation capsule (from a power of 30 KW in a stainless steel capsule). Thanks to water cooling, the capsule can be hermetically sealed. Only air for the engine combustion is requried. This makes the generators particularly quiet.
Only an optimum cooling system can ensure that the temperatures in the sound insulation capsule remain within the range of acceptable values, even in tropical conditions, while also providing the best possible sound insulation.
High salt content and tropical seawater temperatures increase the risk of metals being attacked by galvanic corrosion (electrolysis). Even a very low current can cause a destructive decomposition. For this reason, Fischer Panda uses dual-circuit cooling for all power classes from 3.2 kW. Engine and generator are cooled via an internal cooling circuit. Seawater only comes into contact with the heat exchanger which is made from a high quality alloy (CuNi10Fe).
Thanks to water cooling, the installation of a complex cooling control system (ducting system) is also not necessary. The heat is removed directly via the cooling water system. Ambient temperatures remain constant and there is no risk of other equipment in the engine room being heated.
Thanks to water cooling and sound insulation, generators can be designed to be particularly small, light and quiet.
Complete Solutions for On-board Power Supply
The generator plays an important role within an energy system as it is the largest power supplier on board. It is not usually required to operate around the clock continuously. When demand is low, electricity can also be obtained from other energy sources such as solar, wind, a shore connection or a battery bank.
A combined energy system ensures that the generator is not used at low loads and helps to reduce fuel consumption.
Battery chargers and inverters are also indispensable in the power supply system, e.g. for energy conversion. They determine which energy sources are suitable for supplying which consumers or how quickly their power sources can be recharged.
The modern inverter plays a central role in the complete energy system. The latest "combi-inverters" offer many additional functions. They combine inverter and charger in one unit. They form a power management function by combining power from generator, battery and shore power as required.
Hybrid Power System Consisting of DC Battery Charging Generator with Inverter
The system uses a powerful DC battery charging generator to charge the battery bank. The generator produces a very high charging current. This is far more powerful than the alternator fitted to the main engine. A DC-AC inverter supplies smaller AC consumers by converting energy from the battery bank. Larger consumers can also be supplied temporarily, if the capacity allows.
The generator usually only needs to run two or three times a day for half an hour to charge the batteries.
The system is designed in such a way that the batteries can also be charged via shore power connection as usual.
It is also possible to combine a weaker shore power connection with power from the battery bank so that the fuse does not trip. This can happen if you are trying to draw 16 A from a 10 A shore power connection.
AC Generator with Combi Inverter
In this system, an AC generator is connected to a Combi Inverter. The generator provides a continuous power supply for the largest consumers, e.g. for the air conditioning system or the diving compressor.
If only a small amount of power is required or if only "small" DC consumers need to be supplied, the inverter can supply them with power from the battery bank. If there is excess power from the generator, the Combi Inverter can be used to charge the battery bank.
In ensures the generator is always optimally utilized.
The Combi Inverter can combine shore power when in the harbour and the generator when travelling with the battery bank to provide additional power (starting current).
It is possible to switch between alternating current generator and shore power, either manually or with a transfer switch.
Power Supply for an Electrical Propulsion System on Board
Sustainability and environmental awareness have become important aspects. An increasing number of lake and waterways are prohibiting the use of an internal combustion engine.
Before the main engine is thrown overboard and replaced with an electric propulsion system, it should be not be forgotten that the yacht’s main engine is used during calm periods to top up the batteries. Consideration should be made as to how the battery bank will be charged. This is especially important if a generator is not being installed.
If an electric propulsion system is available, it can be used during sailing to recharge the battery bank. This requires a fixed propeller. The propeller rotates and thus generates electricity. However, this only works when sailing at a minimum speed (6 - 7 kn). The battery can be charged with about 10% of the actual power of the electric motor.
In order to charge the batteries efficiently, a generator should be integrated into the propulsion system when being on a long sailing trip and no shore power connection being available.
Where is the focus?
A hybrid propulsion system combines one single electrical system that can supply both the propulsion system and the electrical consumers on board with power. The battery bank and generator become the central power source for BOTH systems.
If the focus is on supplying power to electric consumers on board, an AC generator is generally the better solution.
If the focus is on sailing, a DC battery charging generator is recommended. When the yacht is sailing at a low speed, the remaining power can be used for the electrical equipment on board. If no power is needed for the other consumers on board, the generator is completely available for charging the battery bank (range extender).
Both generator types have the advantage that cooking can also be done electrically, so that a gas cooker is no longer required.
If the main engine is required, it is possible to install the electric propulsion system in parallel. The electric drive can be used for manoeuvring in the harbour or for slow cruising. the parallel drive system can charge the battery bank with the REGENERATION function when the main engine is running.
When purchasing a complete system for on-board power and propulsion, it is recommended to opt for a supplier who can supply a modular system consisting of all main components "from one source".