Rob,
I don't think that this forum of electric boat enthusiasts is the right group to determine the "correct" methodology for specific techinical questions like you have posed.
But there are a number of resources that can provide answers, like the ABYC and experts like Nigel Calder in his "Boatowner's Mechanical and Electrical Manual".
The ABYC seems to be the only group that has published definitive answers about grounding electric propulsion systems. Their standards state "The boat's propulsion electrical system (e.g. batteries, generators, inverters) should remain isolated from the boat's grounding system. Non-current-carrying conductive parts of the propulsion system (e.g. motor case) should be tied into the boat's grounding system per ABYC E-11 AC & DC Electrical Systems on Boats". This is from the "grounding" section of ABYC TE-30 Electric Propulsion Systems.
So the current carrying parts of electric drive systems should be isolated from the boat's regular (12V) grounding system and the 12V house system should be grounded just like any other boat. I also would assume that any AC system onboard an electric boat should be installed according to the standards defined for any other boat too.
Therefore, like Mike stated before, the propulsion system, the 12V house system and the AC system should be treated as 3 independant systems and the common boat standards for dealing with AC and 12V should be followed. This would include any "conductive path between battery negative and the ocean".
I hope that this answers your question.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, rob linda <rob_linda_2000@...> wrote:
>
> Living on an anchored boat, I would like feedback on the following:Most anchor windlasses use a series (starter) motor with negative ground.The motor housing connects to the windlass, the gypsy, the chain and seawater, creating a conductive path between battery negative and the sea.It is widely believed, that this causes the galvanizing (zinc) of the chain to disappear rapidly.Reason I and many others have an extra switch in the negative windlass lead, which lives in the 'OFF' position, except when the windlass is used.On a similar note, some have an extra negative switch for the starter motor of the main engine, keeping negative and ground separated, to prevent the fast eating away of sacrificial zinc anodes etc.Both windlass motor and starter motor are typically automotive of the shelve.I have understood, that professional marine motors have their negative terminal separated from the housing (ground), for that reason.It seems to me, that an
> ELECTRIC boat forum should have a clear consensus on a simple question as :"Should there be a conductive path between battery negative and the ocean?"
> RobS/V Linda
> http://www.evalbum.com/preview.php?vid=3475http://issuu.com/caribbean-compass/docs/compass_online_november10/27
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