A real world comparison between Mono, Poly, PERC and Dual PV Modules.
* This is a field test and the results are specific for this installation on this location please research which is the best solution for your own situation as the results can be different based on environmental influences.
Total solar yield as of 27/03/2023 when the results were reset:
Mono: 9158 kWh
Split-cell: 9511 kWh
Poly: 9113 kWh
Perc: 9471 kWh
Perc-east: 1970 kWh
Perc-west: 1730 kWh
Motor cruisers are masterpieces of engineering. They pack the comfort of a home into the compact space of a yacht. Wherever you go, you want to enjoy this hard-earned luxury to the fullest. Victron provides an intelligent power grid that adapts to any challenges you may sail into. So you can sit back in a deck chair.
Whether you’re taking the family island hopping for the weekend or if you anchor at a beautiful bay for a week, it’s your holiday and you do whatever you want. This makes the optimal energy solution will vary from yacht to yacht and from owner to owner. With Victron you can power just about any plans, but as an example we illustrated ‘normal’ and ‘heavier’ power profiles in the below for the ‘average’ motor cruiser.
Let's take a look at your Optimal Energy Plan that makes it all happen.
A motor cruiser wouldn’t be complete without a lot of electrical equipment. Most things used to run the boat usually use DC, bigger (household) appliances need AC. How much power does this add up to? Don’t just look at the Watts. A microwave might use 1000 Watts, but only for 4 minutes. A fridge/freezer combo might consume as little as 100 Watts, but is turned on 24 hours a day.
For inspirational purposes we’ve outlined 2 system examples based on ‘normal’ and ‘heavier’ use.
The microwave uses 1000W an hour but is only on for 4 minutes
1000W / 60 x 4 = 0.67 kWh / day
The fridge/freezer combo uses 84W an hour but is on the entire day (normally cooling ½ the day).
84W x 24hrs/2 = 1 kWh / day
A motor cruiser needs good energy storage and powerful conversion to 230V. Charging a battery bank from the engines means you don’t have to turn on that noisy generator when you’re anchored off-shore for the night. Since you might not move for a few days, your house battery should have a generous capacity. As a rule of thumb, we’re calculating energy storage with 48 hrs on board without shore/engine/generator/solar power.
The storage capacity of a lithium battery should be two times the daily power consumption.
Due to its ±50% smaller discharge capacity, the storage capacity of a lead-acid battery should be four times the daily power consumption.
The inverter(s) should be sized to handle the average load continuously and should match the expected peak power current of the loads, which our inverters handle very well (on average 2 x their continuous current).
Normal and heavier power profiles in kWh, based on the daily energy consumption, which should be in balance with the generation.
Storage batteries in Ah, double the capacity using lead-acid batteries.
How do the system design considerations translate into a robust system?
Everything you would expect in a home can also be found on a motor cruiser. All these devices need AC to run. Think of:
The Cyrix BatteryCombiner is the only safe way to connect the house battery to the starter battery (to start your boat’s engines). With a BatteryCombiner you can charge the house battery from the alternator without running the risk of draining the starter battery (which always should be ready to go). When other sources of power are available (eg. shore/solar/generator power), the Cyrix BatteryCombiner will allow bi-directional charging from the house battery to the starter battery.
When the Voltages of the starter and house batteries are the same, use a Cyrix: its current rating should be equal or bigger than the current rating of the alternator.
If the house battery is Lithium and the alternators Amperage is smaller than the house battery, or when the Voltages of the starter and house battery are different: use a DC-DC converter or Buck-Boost.
Battery management systems take excellent care of Lithium batteries, protecting the individual cells of LiFePO4 batteries against over voltage, under voltage and over temperature and will shut down or reduce charging (VE.Bus products only) or disconnect the loads when this occurs.
Victron Energy offers several BMS options, in general the VE.Bus BMS and smallBMS signal separate devices to disconnect the charging (Inverter/Chargers, Cyrix-Li, DC-DC chargers) or disconnect the loads (BatteryProtect, Inverter/Charger), the modular Lynx distribution system features the Lynx BMS and other modules for more control over the DC busbar. For vehicles and boats all-in-one functionalities are available in the Smart BMS versions for Victron Lithium batteries, but also include current limiting to protect the alternator from overheating and BatteryProtect-like functionality to shut down the loads when pre-set critical battery conditions are met.
Victron Energy also offers full flexibility when it comes to selecting a third-party off-grid battery bank (and their BMS) of choice. A large number of well supported Lithium battery manufacturers can be easily integrated through the use of a mandatory GX-device. This flexibility enables our customers to perfectly match their off-grid needs for their unique power situation. When working with unsupported brands, a Victron Energy Battery Monitor is required to pass on accurate state of charge readings to the wider system.
See all our Battery Management Systems
Discharging your battery too far will damage it. Adding a Victron BatteryProtect will disconnect the boat’s electronics when the battery voltage drops below a pre-set level. It will also automatically reconnect everything when the battery is sufficiently recharged.
There is more to a Victron BatteryProtect. The built-in shutdown delay ensures that vital electronics aren’t disconnected in error, i.e. when starting the engine causes a short drop in battery voltage.
A battery monitor is like a "fuel gauge" for your battery. It records how much power is consumed and charged. The battery monitor calculates the state of charge, remaining capacity and time till empty. The battery voltage does not give an accurate indication of how full the battery is (especially not under load). A battery monitor does.
Victron Energy battery monitors keep track of historical data, like the number of charging cycles, deepest discharge, highest voltage, lowest voltage and so on. It will alert you to critical conditions such as low voltage or low charge and can even shut down the entire power supply to avoid expensive battery damage, or start a generator.
Victron offers battery monitors with or without display, Smart versions allow you to track the detailed data and adjust settings in our free VictronConnect app.
Most Lithium systems require a Battery Management System, which can feed battery information to the wider system. In this route a Battery Monitor might become redundant. See Battery Management System for more information. See all our Battery Monitors
Keeping grips on all the systems on board can be a hassle. The solution: tie everything together in a single boat network using NMEA communication standards. Your boat network can include navigation equipment, tank senders, battery monitoring and much more. The status information can trigger alarms and shutdowns, adding to the safety on board. The Cerbo GX now supports the NMEA2000 out protocol, allowing you to monitor your boat’s network of systems from wherever you are.
Motor cruisers have one or two diesel engines to get from harbour to horizon. The engines are designed to run continuously, for days on end. They also come with high-output alternators to charge the engine batteries, drive fuel pumps, etc.
Once the starter batteries are recharged, the engines can also power the boat electrics and recharge the house battery. On motor cruiser you’ll find power hungry DC equipment such as anchor windlasses and bow thrusters. The engines have to be running before you can use them.
A motor cruiser is packed with dozens of electrical devices. These are all connected to the house battery. Think of:
The Buck-Boost converter is used in dual battery systems, where the (smart) alternator and the start battery are used to charge the service battery (of equal or different voltages). The Buck-boost can be used in 12V or 24V systems and is suitable for both lead acid and lithium batteries.
Charging lithium batteries from the alternator
Alternators cannot be connected directly to most lithium batteries. A lithium battery will draw more current than the alternator can supply, which may result in alternator damage. A Buck-Boost DC/DC converter solves this problem: it acts as a current limiter between the alternator and the battery.
How to select a Buck-Boost? The current rating of the DC/DC converter has to be less than the alternator’s current rating. For example: pair a 50 Amps converter with a 60 Amps alternator. In the software the ideal throughput can be defined.
When the charging capacity exceeds the limits of the Buck-Boost, consider working with DC-DC generator(s) sized to the capacity of the battery bank.
The Victron Cerbo GX is the communication-centre of your boat’s installation, allowing you to always have perfect control from wherever you are and maximises its performance. Simply connect through our Victron Remote Management (VRM) portal, or access directly, using the optional GX Touch 50 screen, a Multi Functional Display or our VictronConnect app thanks to its added Bluetooth capability.
The Victron Cerbo GX is an easy to use visual system. Instantly monitor the battery state of charge, power consumption, power harvest from PV, generator, and mains, or check tank levels and temperature measurements. Easily control the shore power input current limit, (auto)start/stop generator(s) or even set quiet periods to avoid starting the generator in the middle of the night. Change any setting to optimise the system, follow up on alerts, perform diagnostic checks and resolve challenges remotely. The Cerbo GX turns any power challenge into an effortless experience.
A galvanic isolator prevents electrolytic corrosion. The isolator is mounted directly behind the shore power connector on board. It blocks DC currents that might leak through the shore power earth terminal. These currents can cause corrosion to all metal parts under water, like the hull, propeller, shaft, etc. The galvanic isolator should have the same power rating as the incoming shore power.
It’s a misunderstanding that galvanic corrosion occurs only in metal and aluminium hulls. In fact it can occur on any boat as soon as a metallic part (the shaft and propeller) is in contact with water. Galvanic corrosion will quickly dissolve your sacrificial anodes, and attack the shaft, propeller and other metal parts in contact with water as soon as the boat is connected to the shore-side supply. It might therefore be tempting not to connect the ground conductor: this is however extremely dangerous because Ground Fault Current Interrupters will not work nor will a fuse blow in case of a short circuit to a metal part on the boat.
The safe option is to use a Galvanic Isolator for non-metal smaller boats, or use an isolation transformer for metal boats or boats with bigger systems.
The generator provides energy when shore power is not available and the boat’s engines aren’t running (or can’t supply enough power to meet the demand). The generator is usually supplemented with a inverter/charger and a battery bank. The batteries act as a backup and allow for quiet periods at night.
Thanks to Victron’s PowerAssist, the generator doesn’t have to be sized for the maximum load. You can use a smaller generator which is cheaper to install, uses less fuel and produces less noise. The inverter automatically bridges the potential gap between supply and demand with support of the battery bank.
A GX 4G module will add mobile internet connectivity to your Victron Energy system. When your system is in range of a 4G network, it will send data to the VRM website and you can monitor the system from your smartphone. The module adds GPS tracking, recording your trips and putting up a geo-fence around the installation. You will get an alert via mail when the system travels outside the geo-fence area.
Victron Energy offers multiple 4G modules and the Global Link 520 modem, which operates without any monthly fees or subscriptions, for the first five years and several 4G modules. See our 4G Modems See our Global Link 520
The Victron GX GSM is a 3G cellular modem that enables GX devices with mobile internet for the system and connection to the VRM Portal, allowing you to monitor your system from remote. When the boat is in range of a 3G network, it will send data to the VRM website and you can monitor the boat from your smartphone. The GSM module adds tracking the boat, recording your trips and putting up a geo-fence around the boat. You will get an alert via mail when the boat travels outside the geo-fence area.
The Victron Energy Cerbo GX is the communication-centre of your systems installation, allowing you to always have perfect control from wherever you are and maximises its performance. The optional GX Touch 50 is a companion to the Cerbo GX, it’s five inch touch screen display gives an instant overview of your system and allows you to adjust settings in the blink of an eye.
Instantly monitor the battery state of charge, power consumption, power harvest from PV, generator, and mains, or check tank levels and temperature measurements. Easily control the shore power input current limit, (auto)start/stop generator(s) or even set quiet periods to avoid starting the generator in the middle of the night. Change any setting to optimise the system, follow up on alerts, perform diagnostic checks and resolve challenges remotely with the free Victron Remote Management (VRM) portal.
The Cerbo GX is an easy to use visual system and turns any power challenge into an effortless experience. Simply connect through our Victron Remote Management (VRM) portal, or access directly, using the optional GX Touch 50 screen, a Multi Functional Display or our VictronConnect app thanks to its added Bluetooth capability.
The house battery stores power for the boat’s electrical system. Motor cruisers typically have large power demands and the house battery should have a generous capacity.
For a house battery you can choose from two types: lead-acid and lithium. There are various reasons to favour one over the other. Here are a few common ones:
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The house battery stores power for the boat’s electrical system. Motor cruisers typically have large power demands and the house battery should have a generous capacity.
For a house battery you can choose from two types: lead-acid and lithium. There are various reasons to favour one over the other. Here are a few common ones:
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On motor cruisers you’ll need an intelligent inverter/charger that automatically switches between various sources to cater for all power needs.
In the marina shore power will be used to feed the boat’s AC grid and charge the batteries. When no shore power is available, the batteries will power both the DC and the AC grid. Power can be drawn from the boat’s engines while sailing. If the power demand gets too high or the batteries get low, the generator will kick in to power the load and charge the batteries.
Thanks to PowerAssist, the generator doesn’t have to be sized for the maximum load. You can use a smaller generator which is cheaper to install, uses less fuel and produces less noise.
If you don’t have a generator on board, a Multiplus is all you need. With a generator on board a Quattro is the better choice.
We strongly recommend 24 Volts for new boats. The higher voltage is simply a better choice when it comes to meeting the power demands of a motor cruiser. If your boat’s system is based on 12 Volts, select a 12 Volts unit instead. If you have dissimilar battery banks, consider charging them using a DC-DC converter, or have it power several dissimilar appliances with a different voltage than the house battery.
Generally speaking, a 3 kVA unit will be big enough, unless the power consumption is higher than average. For example: when you have an air conditioner on board. If this is the case, choose a 5 kVA unit.
The Victron integration between our GX range and several leading Multi Functional Display manufacturer brands enables you to easily connect an MDF to the heart of your power system such as the Cerbo GX, or the GX enabled MultiPlus-II GX. Once connected you can easily monitor and control your boat’s power system, right on your Glass Bridge.
Usually shore power is available in the marina; it is used to run large AC equipment on board and recharge the batteries. Larger boats need a three phase supply. Sometimes shore power can’t provide enough power to cater for the total AC load of the boat. It might also just be single phase.
Often shore power is limited in how much power you can draw, i.e. just 10 Amps. Berths with higher ratings might not always be available. Victron inverter/chargers allow you set a maximum shore power current. Now you can charge your batteries and turn on any equipment without blowing a fuse. Thanks to Victron’s PowerAssist, the generator and batteries can automatically bridge the gap between supply and demand.
Sometimes shore power is less than perfect. You might run into voltage drops if you’re at the far end of the harbour. There could also be power surges, which could harm sensitive equipment on board. Victron’s inverter/chargers smooth out these problems and turn bad power into perfect power.
Solar panels won’t be able to cover all the power needed, but they can reduce the running time of the generator and fuel costs.
A solar charger - also called MPPT controller, harvests the power from the solar panels to charge the house battery. Solar chargers have the same charging cycles as our regular, fully automatic, battery chargers. When your boat is moored without shore spower, solar power is a great way to keep the batteries charged.
In a marine environment, the performance of solar panels changes constantly. Victron’s solar controllers use ultra fast maximum power point tracking to squeeze up to 30% more power out of your panels.
See our Solar Calculator to size the solar panels and select a MPPT charger
Solar panels won’t be able to cover all the power needed, but they can reduce the running time of the generator and fuel costs. Victron offers a wide range of highly efficient solar panels that are just perfect for marine use.
The starter battery is needed to start your boat’s engines. These batteries are different from house batteries and engineered to deal with a large discharge current. The starter batteries should be ready to go. Always use a BatteryCombiner to connect the starter batteries to the rest of the electrical system; it prevents an accidental drain of power.
The GX Touch 50 display allows you to have an instant overview of your system and adjust settings in the blink of an eye. Simply connected to the Cerbo GX with one cable, its super slim 5 inch waterproof design and its top-mountable setup bring a lot of flexibility when creating a crisp and clean dashboard.
All Victron products on your boat can be monitored and controlled from the palm of your hand. Just connect the VictronConnect App via Bluetooth and you’ll have direct access to values like battery voltage and current. You can also turn devices on or off, as well as change their settings.
See what the VictronConnect app can do
The Lynx Distributor is a modular DC busbar, with locations for four DC fuses. It will monitor the status of each fuse, and indicate its condition with a LED on the front. When connected to a Lynx Smart BMS or Lynx Shunt, the status of the fuses will be visible in VictronConnect and VRM (when the Lynx Smart BMS is connected to a GX-device).
Multiple Lynx Distributors can be used to connect all the DC-loads and charge sources on one side of the BMS, on the other side, a Lynx Power In (without fuses) or another Lynx Distributor (with fuses) can be used to connect the battery bank to the modular busbar.
Lynx Distribution system
This product is part of the modular Lynx busbar system that also provides the Lynx Smart BMS, a dedicated Battery Management System for Victron Lithium Smart Batteries (for non Victron Lithium batteries, use the Lynx Shunt).
See all Lynx modules
Monitor and manage your Victron Energy systems from anywhere and catch potential issues early by setting alerts and alarms. With VRM you are always in perfect control from wherever you are.
VRM works with a GX-device such as the Cerbo GX with internet connection, the GlobalLink 520 or GSM LTE 4-g for smaller systems.
Monitor the battery state of charge, power consumption, power harvest from solar, generator and mains in real-time. Optimise the energy harvest and usage with history graphs and detailed analytical reports. Catch potential issues early by setting alerts and follow up on alarms to prevent definitive system failure.
Easily control the shore power input current limit, switch on the inverter, (auto)start/stop generators or even set quiet periods to avoid starting the generator in the middle of the night. With VRM you can change any setting, follow up on alarms, perform diagnostic checks and resolve challenges from wherever you are.
See all our GX-devices
The Lynx Smart BMS is a dedicated Battery Management System for Victron Lithium Smart Batteries (for non Victron Lithium batteries, see below). There are multiple BMS-es available for our Smart Lithium series of batteries, and the Lynx Smart is the most feature rich and complete option. Its main features are:
The dedicated battery management system (BMS) protects Victron Lithium Smart batteries against deep discharges, overcharging and high temperatures. When critical values are exceeded, the BMS acts immediately: loads are disconnected physically in case of a deep discharge and charging is stopped when there is a risk of overcharging. High temperatures trigger an immediate end to both charging and discharging.
Battery monitoring is built into the Lynx Smart BMS; no separate battery monitor is needed. With Bluetooth the battery bank can be monitored with VictronConnect, when connected to a GX-device, also with VRM, our remote monitoring solution.
This product is part of the modular Lynx busbar system that also provides the Lynx Distributor which is a modular DC busbar containing 4 DC fuses and monitors their status in VictronConnect and VRM and other DC connections to handle distribution, fusing, battery monitoring and/or Lithium battery management.
The Lynx busbar system can also be used for DC distribution and monitoring of non-Victron Lithium batteries. In that case, replace the Lynx Smart BMS with the Lynx Shunt VE.Can for monitoring of any other battery. See all Lynx modules
Power consumption will vary from yacht to yacht and from owner to owner. The Optimal Energy Plan should always be designed with the cruisers specifics in mind. However, to get you started, here are two examples - with a normal and a heavier daily energy consumption - of Optimal Energy for a motor cruiser.
Please note that many more factors come into play when designing and installing your optimal solution: your Victron Professional will gladly help you with that.
Our well established global network of local Victron Professionals is dedicated to help find an optimal solution for your challenge.
At Victron we find it essential that customers are serviced and supported quickly and competently. This is why our global network of Victron Professionals pack the highest level of technical know-how and are committed to deliver repairs as fast as possible.
So you can start or continue your journey, wherever you’re headed.
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