Leaderboard

For a vehicle there is a certain procedure to follow to check for parasitic drain and the same practice should work for your boat. Make sure everything in the boat is hooked up but turned off. Disconnect your main negative battery connection and put multimeter leads set on mA between the battery and the cable. For a vehicle normally what would be normal current draw is in the area of 25 milliamps (.025A) Again, in a vehicle if the draw is much higher than that then what you do is start pulling fuses one by one until hopefully the current draw drops down to normal when you pull a specific one which will isolate the faulty circuit. In your case on a boat I would think that current draw should basically be zero or very close to it and if not it will be much simpler as there are much fewer circuits for you to isolate, so if you read 100mA for example disconnect your different units one at a time until the current draw drops back to zero or close to it and that will tell you which circuit is causing the problem, whether its bad wiring or an internal issue with one unit or even a switch for that matter. Good luck.