This is my first winter with the boat. I was wondering if there is a particular order I should unhook my batteries, so I do not cause a short or shock myself. I plan on taking out the batteries from the boat, checking the fluid levels on them, then trickle charging each battery. Since I have never done this I could use any help I can get. If the fluid levels were low I was just planning on filling up the batteries with distilled water. Is this correct? Any pointers would be appreciated.