Abstract: A method for monitoring the state of health of at least one contactor in a battery pack, wherein the battery pack comprises at least one battery cell, a first interface line and a second interface line, wherein at least one switchable first contactor is arranged in the first interface line between the interface and the at least one battery cell, and at least one switchable second contactor is arranged in the second interface line between the interface and the at least one battery cell, comprising steps for the measurement of a first differential voltage across the open first contactor and/or the measurement of a second differential voltage across the open second contactor, and the monitoring of the state of health of the first contactor on the basis of the measured first differential voltage and/or determination of the state of health of the second contactor on the basis of the measured second differential voltage.

Abstract: A method for charging an auxiliary voltage source that provides power for at least one additional component, the additional component being in addition to an electric drive that is powered by a main voltage, is described. The method includes electrically connecting a protection and/or control circuit to the main voltage source via a DC-to-DC converter configured for power supply, and to the auxiliary voltage source via a reverse blocking valve. The method further includes electrically connecting the main voltage source to the auxiliary voltage source via a charging device. The method still further includes charging the auxiliary voltage source via the main voltage source.

Abstract: The invention relates to a boat with an electric drive and a main voltage source, which provides power for the electric drive, and with an auxiliary voltage source, which provides power for at least one additional component. According to the invention, a charging device for charging the auxiliary voltage source is provided, wherein the charging device is connected to the main voltage source.

Abstract: The invention relates to a boat with an electric drive and an electrical store which has at least one storage element and a positive and a negative pole. The poles are in current-conducting connection with the storage element. An isolating means for isolating the current-conducting connection between at least one of the poles and the storage element is provided, and is operatively connected to an emergency stop switch which is directly activatable by the user of the boat.

Abstract: A cooling system and method is disclosed. A coolant line is in thermal contact with an electric motor of a boat drive. Coolant is pump able by a pump through the coolant line. The coolant line is in thermal contact with a component that is spatially separate from the boat drive. The coolant line has a first line section which is in thermal contact with the electric motor, a second line section which is in thermal contact with the component, and the first line section is detachably connectable to the second line section.