I recently ended a 3 year lease of a BMW electric car and I am very impressed by the state of current matters/charger and motor technology. I cannot wait untill it becomes affordable enough for widespread marine use. What's not to like about super fast charge and discharge, small, high capacity battery banks that don't emit explosive gases? IIRC a Tesla Powerwall can run a whole house air conditioning system for over 24 hours in desert heat, imagine that system on a boat.