Electric Energy Storage

Electric Energy Storage



The Mega-Guard Electric Energy Storage (EES) is an advanced system for electric energy storage for marine environment. Sailing and silent running on stored electric energy becomes a reality with Mega-Guard EES.
The  Mega-Guard EES consists of the following main components:

  • GreenBattery
  • Master BMS
  • Battery Rack

Energy storage systems in between 40kWh and 12MWh can be built with Mega-Guard ESS.









GreenBattery makes use of the extremely safe LiFePO4 (or LFP) chemistry. Safety can be compared with traditional lead acid batteries and are much safer than Li-ion technology which is used by other marine battery manufacturers. In addition, life time and temperature range of LiFePO4 are much better when compared with Li-ion batteries. GreenBattery has relatively low weight and small volume per stored kWh. In fact, GreenBattery is one of the lightest batteries available for marine energy storage.

Each GreenBattery has a capacity of 10kWh and a nominal DC bus voltage of 96VDC. GreenBattery can be cooled either by forced air or by liquid. GreenBattery is totally enclosed and includes a built-in slave battery monitoring system which communicates with the Master BMS. GreenBattery fulfils the latest class requirements and includes a pressure based safety release which should be vented to the outside environment. Up to 10 GreenBatteries can be wired in a string and a Master BMS monitors and controls the string. Up to 120 strings can be wired in parallel.










Master BMS

The Master BMS monitors and controls a string of GreenBatteries. All external connections (DC bus, Ethernet, cooling and  venting) of a string are made on the Master BMS.  A 5,7” touchscreen Operator Panel with built-in controller is mounted in the front of Master BMS. The state of charge (SOC), voltages and temperatures of a string can be read on the touchscreen Operator Panel.
The controller takes care of cell balancing, cooling control and safety functions. In addition, the controller is equipped with quad Ethernet ports for communication to external Mega-Guard High Power Inverters for battery charging and to a Mega-Guard Energy Management System. The Master BMS contains as well a DC bus contactor with pre-charge and includes air or liquid based
cooling devices for the GreenBatteries. Two versions of Master BMS are available:


  • Water/glycol cooled ; the Master BMS is equipped with a temperature controlled 3-way cooling valve. The cooling flow is bypassed when GreenBattery temperature drops below 22°C by energizing the valve. The EES does not heat up the battery room.
  • Air cooled ; the Master BMS is equipped with fans for proper air circulation inside the Battery Rack. The battery room should be equipped with an air conditioner to take away the heat (0.22kW for each GreenBattery).






Battery Rack

GreenBatteries and the Master BMS are placed in a specific designed Battery Rack. The Battery Rack contains cooling channels (air or liquid) and makes it possible to exchange a GreenBattery by sliding out and in.  Battery Racks are supplied in two different mechanical lay-outs: a vertical one for space saving and a horizontal one which is applied when not enough room height is available.
Battery Racks need to be installed in a battery room in accordance with class regulations.

The following Battery Racks are available:
















Mounting & dimensions


Sales and service

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Contact information

Praxis Automation Technology
Zijldijk 24A,
2352 AB Leiderdorp
The Netherlands

+31 (0)71 5255 353

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