Hi I wanna buy same one. Is it ik for sea water ? 80ah battery how many hours full speed= 1h ? and how many half speed= 2 hours ? Also some other chinees motors with same specs promise 2 times faster max speed . Lies ? Any leaisure battery ok , or must buy deep cycle battery ? Ok to discharge battery to 0 or 10% every time when using motor or only discharge battery by 50%? Lol if only by 50% then 30 min sailing at full speed and 1 h at half speed with 80ah battery ? Thanks !