Marine batteries as energy storage and power supply for propulsion significantly reduce fuel consumption, maintenance costs and emissions. With improved capacity-to-weight ratio from lithium-ion technology and growing demand for lower emissions, batteries have become an ever-increasingly attractive option for the large-scale supply of energy in the maritime sector. COBRA is an advanced battery system employing inherent safe and environmentally friendly lithium iron phosphate cell technology and taking the special requirements of maritime operation and classification into account. Any scale of power storage is available by freely configuring modular units in standardised racks of up to 1,000 V DC. They include integrated Battery Management System (BMS), gas exhaust and air or water cooling for safe and reliable operation. The Compact Battery Racks are being assembled and tested in their own built production facility near the Hamburg headquarters of Becker Marine Systems.