4.4 Propulsion Specification

Note: All forms of powered propulsion must be electrical.

4.4.1 Battery

All batteries must be sealed to reduce the hazard from acid or caustic electrolytes. The open circuit voltage may not exceed 60V [DC]. During the 2023 competition, Njord will be able to lend batteries to participating teams. The reason for this is to simplify the transport of the team's vessels to Trondheim, and to ensure that the batteries comply with safety standards. The teams are not required to utilize the provided batteries, but are responsible for ensuring that their chosen batteries are within safety requirements. There will be professional personnel present at the competition approving the teams’ power supply arrangement before teams are allowed to compete.

4.4.1.1 Documentation and general requirements

All battery cells used in the competition must be commercially available. The teams must disclose all data related to the batteries in the Technical Report. This must include a detailed overview of the battery setup and the “materials safety data sheet” which is supplied by the manufacturer. The purpose of this data is to provide Njord with necessary information in case of an emergency. For teams planning on utilizing energy sources other than lithium battery cells, they must contact Njord for further detailed requirements.

3.4.1.2 Housing, fastening and material selection

• The batteries and the housing must be designed such that they will remain fixed in the case of the boat capsizing.

• The battery housing must ensure that no electrolyte could flow out of the housing in case of a battery malfunction.

• The housing must also be constructed of materials resistant to the electrolyte of batteries, as well as being fire-resistant.

4.4.1.3 Battery Management System (BMS)

• A properly functioning BMS must be installed with the purpose of monitoring all individual battery cells.

• The system must monitor both the battery’s voltage and temperature. It must also be capable of shutting down the system when necessary.

• The BMS must be capable of shutting down when voltage, currents (charge and discharge) or temperature is outside the specified safety limit according to the manufacturer.

4.4.1.4 Testing

• A demonstration of the BMS (voltage levels of the cells) must be shown to Njord during the testing of the vessel.

• Njord does not take responsibility for incorrect functioning of the BMS, unbalanced battery cells or any other kinds of failures of the batteries that may appear during testing.

4.4.2 Speed

The vessel must at no time exceed the speed limit, which is set to 5 knots. This is important to ensure a safe competition without any unwanted collisions or accidents.