Our client use Polinovel AF Series 4 units x 12V 300Ah lithium battery to replace the original 12 x 1000ah Sonneschien 2 v OPZV gel cells. Series-connecting gets a 48V 300Ah battery system. The series-connected 48V 30Ah lithium battery is run with a 5000 watt Victron Multi Plus inverter to power the bow thruster and other systems on the rental boat.