Connected to shore you will be fine. At anchor you will have a problem. You are forced to live with it. Remember if you cant make more electric you will have to reduce your use. As you go along try to convert lights to LED and refrigeration may be out. If you have a large enough battery bank you may be OK for several days till you return to dock charge. You dont want to run your outboard for 24 hours just to keep the drinks cold. Best of luck
That derelict boat was another dream for somebody else, don't let it be your nightmare and a waste of your life.