Water Taxi Rotterdam launches battery powered ships

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The city of Rotterdam (NL) expands its fleet with new electric water taxis. Last month the first of in total 5 battery powered ships was launched officially. MG supplies the redundant battery system for these electric passenger boats. Shipyard Alumax will build the ships and takes care of the complete installation. MG collaborates to achieve one shared goal: a pleasant and emission-free water taxi trip !

Zero-emission passenger vessel

These water taxis will be used for passenger transport over the water in the harbour and city centre of Rotterdam. The total project concerns 5 battery powered all-electric ships. In addition, one hydrogen water taxi will be built in the near future.

RS battery module

In total 16 RS battery modules are powering the electric drives. Basically there are two reasons why this module was chosen. Firstly, the battery must withstand high charging currents. For instance this is needed for fast charging during the day. Secondly, the battery system should last a long time. In other words, the battery must be suitable for many charging cycles.

Both the electric drives ánd the MG battery system operate on the same system voltage. The system voltage of a single individual RS battery module is 51 Vdc. So, installing two of these modules in series configuration results in a battery voltage of 102 Vdc. As a result the Bellmarine DriveMaster electrical drives can be directly powered at the required voltage of 96 Vdc. This means, there are no energy losses in power conversion.

During a day of sailing, the water taxi needs enough battery capacity. A total of 8 parallel battery strings guarantee the requested range.

Two electric drives operate on a system voltage of 96 Vdc.

The 102 Vdc battery bank provides the power directly to the drives.

This results in a high efficient system. There are no energy losses in power conversion.

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Charging

Charging of the batteries is done by a standard EV charging station. This makes it possible to charge to any EV charging station. Another benefit is that automatic current sharing is applied when two battery powered ships are charging at the same charging station.

A special interface is installed and integrated in the MG battery system to achieve this functionality.

Master LV, the BMS to connect 72V and 96V electric drives

A prerequisite for a lithium-ion battery bank is a BMS. This abbreviation stands for Battery Monitoring System. In fact the BMS is the heart of your lithium-ion battery system. MG offers a BMS especially for the 72V and 96V market. This is the Master LV.

Firstly and most importantly the MG Master LV 72V / 96V ensures the cell balancing (BMS) of the battery bank. Secondly, the Master LV contains all essential components which are required for a safe installation. In short these built-in components are:

  • Safety contactor
  • Pre-charge function
  • Shunt
  • DC distribution
  • Fuse box

The internal DC busbar of the Master LV makes it possible to connect a 96V electric drive  directly to the battery system.

ES-Trin regulation

Above all, the safety on board for the 40 passengers must be guaranteed. For that reason the MG lithium-ion battery bank will get an approval according to the European ES-Trin (IEC62619 and IEC62620) regulations.

Redundant lithium-ion battery banks

These ES-Trin regulations require a redundant battery bank. Therefore these water taxis are equipped with two Master LV’s (BMS). One Master LV for starboard side and the other Master LV for port side.

To sum up the main benefits of the combined battery mode of the Master LV.
Firstly: Redundancy.  For example one battery bank fails during operation. As a result this battery bank will go offline. Meanwhile the remaining Master LV will be still in operation. The parallel battery bank guarantees continuous power for the electric drives.
Secondly: Scalabitiy. Install two or more battery strings. Extension of the capacity is easy;
Thirdly: Service. Easily replace batteries from a string, without taking the system down.

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Specifications Water Taxi MSTX-31

Capacity: 40 people
Length:12 m
Displacement: 7700 kg

Design and shipyard

Triple Marine, The Netherlands
Alumax boats, The Netherlands

Electric propulsion

Drive: Bellmarine Drivemaster 20W
Quantity: 2 pieces, one on starboard and one on port
Nominal power: total 30 kW
Intermittent power: total 40 kW
System voltage: 96 Vdc
Cooling: liquid cooled

Battery type
Model: MG RS Battery Module
Voltage: 51 Vdc
Capacity: 7.4 kWh
Series configuration: 2 in series, 102 Vdc
Parallel configuration: 8 parallel strings
Total number of modules: 16
Redundant battery bank: yes
Total capacity: 115,2 kWh
Cooling: liquid-cooled
Master LV: Two units, 96 Vdc – 500 A
DNV-GL: yes
ES-Trin IEC62619 and IEC62620: yes, available from Q3-2021

Single line diagram of the battery system

battery powered ship single line diagram

Related links

Top Systems B.V.
https://www.top.systems/

Alumax boats
https://alumaxboats.nl/

Triple Marine Yacht Design
https://triple-marine.nl/

Watertaxi Rotterdam
https://www.watertaxirotterdam.nl/

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Related products

RS series
Product information of the installed batteries
https://www.mgenergysystems.eu/products/mg-rs-series/

Master LV
In addition click on the link below to gain more information about the installed BMS
https://www.mgenergysystems.eu/products/mg-master-lv/

Energy Monitor
Furthermore for stand-alone systems use this advanced touch-screen monitor.
https://www.mgenergysystems.eu/products/mg-energy-monitor/