LTW battery team had installed lithium batteries into two pieces of Nautitech Open catamarans. 300Ah of LTW cells replaced original system battery of the yacht and allowed more then two times more runtime of ships accessories with generator turned off. Not only longer battery lifetime and more power is possitive effect of this battery swap. Lithium battery can also significantly decrease runtime of generator and ship engines and decrease fuel consumption and service costs. Battery is protected with LTW BMS with color diplay, protection from over discharging and balancing feature was implemented into complex system of the catamaran.