By Olmar van Beurden

The battery in our boat is being charged by the solar panels on the boat. The battery is used during take-off and at times when the incidence of sunlight on our solar panels is limited. This makes us less dependent on the weather conditions. Because the capacity of the battery from last year was limited by the regulations, now it is important to build the most efficient battery possible. We do this by minimizing the electrical resistance, by selecting the ideal cells and by ensuring that the battery operates under its optimum working conditions.

The battery in our boat is made up of individual cylindrical lithium-ion cells. Due to the number of cells in series, we can design the voltage of the battery at the desired level and the number of cells in parallel is then determined by the desired capacity. The cells we use are lithium nickel manganese cobalt oxide cells. These cells have a very high energy density and high power density.

The condition of the battery is constantly monitored by the battery management system. This system is made by the team itself and monitors the voltage and temperature with the help of various sensors. If the temperature becomes too high, the battery management system switches the cooling on and by measuring the voltage it also ensures that the battery cannot be discharged too far or charged. The system also ensures that all cells are balanced so that one cell is not charged more than another cell.