It is extremely unlikely that your zinc problem is related in any way to the 12 volt system inside the
boat. You are tilting at windmills, fixing the wrong problem.
Your first line of defense is a
Galvanic Isolator in the ground lead of your
shore power connection. It is only a $100 expense and can pay for itself in one year of zinc savings.
Once it is installed, measure the AC voltage across it. The
paint bubbles you describe are a symptom of AC leakage that forms bubbles of sodium hypochlorite under the paint. If the AC voltage is greater than about 0.5 volts you need to troubleshoot problems in your AC
wiring and add a Galvanic Capacitor across the
Galvanic Isolator to bypass the AC
current if needed.
Rather than trying to isolate the
battery system, there is less chance of DC
electrolysis from the battery causing problems if ALL the negative connections are solidly bonded to the hull. That way they have to be at the same voltage as the hull and minimize introducing extra problems.
I lived aboard a
steel boat for nearly 15 years, send me an
email to
tech@yandina.com if you have any questions.
Interested in smart boat technology, networking and all things tech
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