Exploring the most beautiful places of the world with the energy of Lithium Marine Batteries

Nordhavn explorer with lithium marine batteries

Exploring the most beautiful places of the world by boat is something that everybody is dreaming about at some time. The owners of the Nordhavn N68 had the same thought in 2010. They sold their house and started to live on this expedition cruiser. Since that time they lived on the boat and sailed the seas to visit the most beautiful remote places out there. They traveled from the Bahamas up to the north to see the arctic ice in the polar region. Crossing the ocean from the USA to Europe was also part of the journey.

The Nordhavn boats are expedition cruisers that can be operated by only two persons. The unique points of these cruisers are safety, reliability and having some luxury and comfort.

More info about the boat: https://youtu.be/U8bMRHrsQ0E

Lithium Marine Batteries Provide An Significant amount of Energy 

Being in remote places for up to two months takes good planning and of course enough provisions for that time. This means that there needs to be enough fridge storage to keep it cool for longer periods of time. Which also requires a significant amount of energy. If the energy system is not sufficient, the fridges will not work and the provisions are spoiled. The reliability aspect of all the systems on board is therefore very important. Nobody want to be in a remote place when systems fail and cannot be repaired or there is no backup system. Therefore most systems are duplicated or setup as a redundant system. Especially the electrical system which provides power to all the equipment on board i.e. fridges, watermaker, lights, navigation, radio etc.

Marine Battery Replacement

Last year the owners decided to build a new boat, also a Nordhavn N68. They reached out to MG Energy Systems for the marine battery system. The energy storage of the previous boat was supplied by traditional Lead-Acid batteries. Now looking at a higher energy consumption, due to the additional equipment, and the ability to stay longer periods at remote places, more energy storage is needed. 

Some of the questions of the owners where:

  • “Can we have more energy in the same space with lithium ion batteries?”, 
  • “What is the reliability of the batteries?”, 
  • “How long will the lithium marine batteries last?”, 
  • “How safe are lithium marine batteries?” 
  • “Is it possible to connect solar panels to the marine lithium batteries?”

After explaining all the possibilities and advantages of the marine lithium batteries, they were convinced.

Absolute Silence

Another advantage of a larger energy storage system is that the “silent” periods can be longer. This means that being at remote locations the generator can be off, creating an absolute silence for hours. In combination with solar energy this period can be extended ever more.

Configuration of the Electrical System with Lithium Marine Batteries

An electrical system is setup together with the engineers of Nordhavn with all the requirements i.e. safety, reliability and simplicity.

Basically the system consists of the following components:

The batteries are evenly split into two 24 V banks each controlled by their own master BMS, the MG Master LV. This provides the system to be redundant. Charging of the lithium batteries will be done by either the alternators during sailing with the main engine, the Quattro’s and Skylla-I’s during shore connection or generator operation. The Victron Quattro’s provide the 230 Vac.

MG redundant lithium marine battery system

Selecting the components for this system was not the hard part. The main issue always lies with the questions “How do I integrate all the components?”, “How will all the parts work together?”. All components in the energy systems need to work together as a whole. That is key.

MG Lithium marine battery system integration with Victron Energy

As from 2009 up till now MG Energy Systems is collaborating with Victron Energy on integration of Lithium batteries. This long period of working together results in a high level of integration of MG’s lithium batteries and Victron’s charger/inverter equipment.

The basic control of the components is done by the Victron CCGX. The MG Master LVs are connected to the VE.CAN network of the CCGX, sending charge and discharge parameters. The CCGX is connected to the Victron Quattro’s using VE.Bus. DVCC is used to control the Quattro’s. The BlueSolar MPPT and Skylla-I’s are controlled directly from the MG Master LVs using VE.CAN.

More information about compatibility with Victron Energy.

Redundant marine battery system

By splitting the lithium ion marine batteries into two battery banks, redundancy is created. The MG Master LVs are set in parallel and the CAN-bus is connected to each other. Configuring the Master LVs in “Battery combined mode” they will communicate together and use a smart start-up system making it possible when there are State-Of-Charge differences in the battery banks during start-up, the MG Master LVs will wait until the output voltage is the same as the battery bank voltage before closing the main contactor.

MG Master BMS lithium marine batteries

Another issue with making a redundant battery system is that there will be only one pair of Inverter/chargers connected that needs to be controlled by two battery banks. And if one battery bank fails it should still be controlled by the other battery bank. This issue is solved by combining the control parameters from the MG Master LVs to “see” it as one battery bank. In this way it is possible to control the inverter/chargers with these combined parameters.

In practice this means there is a script installed on the Victron CCGX that combines the DVCC (Distributed Voltage and Current control) parameters and control the Victron Quattro’s. For more information ask your dealer or MG sales contact person about the possibilities.

Lithium battery monitoring

Monitoring of the lithium batteries is done by MG’s Energy Monitor. This smart touch display can be connected to the master BMS (Master LV). In this case there are two battery banks each with their own master BMS and their own MG Energy Monitor.

MG Lithium battery monitor

The smart display shows all relevant information from the master BMS. Cell temperatures and cell voltages of each battery module can be shown. It is also possible to change settings and connect to a WiFi network. With this last option it is possible to monitor all data of the battery system remotely with our MG Energy Portal.

There is also a Victron CCGX display installed which will monitor the battery banks as well. The installed “combined battery” script will add a new combined battery device to the CCGX which shows the combined data of the two battery banks.

MG LiFePo4 lithium marine batteries

Charging Lithium marine batteries with alternators

Charging Lithium batteries with alternators is not as easy as it sounds. Alternators are designed to charge traditional Lead-Acid batteries. As they have a high internal resistance the alternators can easily charge those batteries. Lithium batteries have a low internal resistance which causes a high current from the alternators at low speeds where they have low cooling and will overheat and even damage the alternators. The solution to this is to limit the charge current when the alternator reaches a certain temperature. This can be performed in two ways. First is, when using a standard alternator with built-in voltage regulator, to use the MG alternator limiter. It limits the current when the alternator reaches a certain temperature and when the batteries are fully charged. The second way is, when an alternator with external regulator is used, to use the Wakespeed WS500 to control the field of the alternator. This also limits the current when the alternator reaches a certain temperature or the batteries are fully charged. Both devices are connected to the MG Master LV with CAN-Bus to control the charging process.

Marine high power alternators charging lithium marine batteries
WS500 alternator regulator

Conclusion

New journeys will start for the owners this year with their newly built expedition cruiser which is almost ready. We wish them good luck and safe travel during their trips.

Have a look at our website and products to learn more about MG Energy Systems marine batteries and system solutions.

Reference links