This is a question that evokes a lot of new questions: How will you use the battery system? What will be the load-profile of your vessel? and many more. If you want some insights as a good startingpoint, you can have a look at our Whitepaper: 10 points to consider when looking for a maritime battery system 

The Octopus Series modules are suitable from 100kWh systems up to multipje MWh systems. Thanks to several engineering designs our system performs well and eases integration for all size systems, even over 20MWh.

The Octopus Series is our flexible energy storage platform, designed for maritime applications. The Octopus platform is a chemistry-agnostic solution that allows shipowners and system integrators to choose the technology that best fits their project.

Currently the Octopus Platform can be combined with four of our modules:

• High Energy
• High Power
• Lite
• Lite XL

The system is designed with EST-Floattechs safe by design mentality, experience with the Green Orca and background as system integrator, with  hard- and software safety features.

Solid State Breaker

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Class type approvals

The safety of the system is testified by Type Approvals from maritime class societies: DNV, Lloyds Register, Bureau Veritas and RINA.

This built in safety-feature prevents thermal events in one battery cell from spreading to the adjacent cells inside the battery, without relying on active compontens such as sensors or electronics.

When using electric propulsion for ships, electric motors drive the propellers instead of the ‘traditional’ diesel motors. These electrical motors get their power form an electrical source on board such as a battery pack, otherwise known as an Energy Storage Solution.

Electrical propulsion offers several clear benefits:

• Zero emission shipping (with batteries): a fully electric ship operating on an Energy Storage System, produces no exhaust emissions, which helpt meeting environmental regulations and keeping air clean, which is vailable in ports, protected areas and in general better for the environment wheter it’s in rural or densely populated areas.
• Lower noise: Electric motors run quielty. his makes for a more comfortable experience for passengers and crew, and less noise disturbance to marine life.
• Reduced Maintenance: With fewer moving parts and no complex gearboxes, electric propulsion systems typically require less maintenance than diesel engines​.
• Operational Cost Savings: Electricity can be cheaper per unit of energy than marine diesel fuel. Over the long term, an electric or hybrid vessel can have lower fuel (energy) costs and potentially longer time between overhauls.
• Instant Torque and Maneuverability: Electric motors deliver instant torque, meaning a ship can have very responsive thrust control. This improves maneuverability – for example, an electric ferry can accelerate quickly and precisely control speed when docking. It also allows dynamic positioning systems to react faster.

Electric ship propulsion differs from traditional diesel engines in several key areas. Diesel fuel has a far higher energy density than batteries, allowing diesel-powered ships to travel much longer distances without refueling, while battery-electric ships are best suited for shorter routes due to their more limited range and the space and weight required for large battery banks. However, electric motors are highly efficient—often over 90%—compared to diesel engines, which lose much of their energy as heat. When electricity comes from clean sources like shore power, electric propulsion also offers clear environmental advantages. Electric systems are especially efficient in variable operating profiles (e.g., maneuvering or port operations) where diesel engines struggle with low-load inefficiencies and increased wear. Maintenance is another differentiator: diesel engines require frequent servicing, while electric motors and batteries have fewer moving parts and are generally more reliable, though they do require vigilant battery management. Environmentally, electric ships emit no exhaust gases when running on battery power, in contrast to the CO₂, NOx, SOx, and particulates emitted by diesel engines—making electric propulsion ideal for meeting strict regulations in emission control areas. Although diesel still leads in range and energy density for long-haul shipping, electric and hybrid systems are gaining ground thanks to their efficiency, lower maintenance, cleaner operation, and suitability for short-sea and port-based operations. Many vessels now combine both systems in diesel-electric hybrids, leveraging diesel’s range with the efficiency and emissions benefits of batteries—a trend expected to grow as battery technology continues to evolve.

EST-Floattechs NMC cells have the most stable chemical combination in the market. Whilst LFP cells are regarded as a more safe option, as they are more thermally stable, the cells can experience expansion during charge and discharge cycles, which can become a hazard if not taken into account with the system design.

This is a key factor as space and weight are often limited on board. Therefor if a system is too large or the batteries can’t give the amount of energy needed, a system can become

It depends on the total capacity (kWh) on board of your system, a higher capacity allows for longer electric operation. But the power demand, determined by the size, speed, propulsion type and other on board systems plays a key role in how long you can use the system on board. Whic brings us to the operation profile:

• Fully electric
• Hybrid
• Peak Shaving applications
• Hotel Loads

This is the key element for which you can use the battery system and which impacts on how long the system can go between charging.

This depends on several technical and operational factors. From the C-rate, to the capacity and how you use the system. But for example, they Frisia fully electric ferry can fully recharge the system within 7 minutes

Each battery has a safe charging limit, defined by the C-rate, also known as charge or discharge rate. A measurement that described how fast a system can be charged or discharged.

It is expressed as a multiple of the batteries capacity, for example:

• 1C means the battery can be fully charged or discharged within 1 hour
• 0,5 C means it will take 2 hours
• 2 C means it will take 30 minutes

This an important element for the system as a higher C-rate means faster performance of the batteries, but also comes with higher temperatures and more stress on the batteries. That is also why cooling is more important.

The Battery Management System (BMS)

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