Re: Inverter grounding and other details

Jose Venegas

Hi Bob,
Thank you for your replay.  I think your approach is OK, particularly for a small inverter.  However, for a 5KW inverter, I also want to run pretty much all the 220V devices in the boat (obviously not at the same time). The inverter will be located next to the battery bank to minimize the distance to the batteries and make sure the inverter is in a dry place.  I already had the experience of having a saltwater leak which sprayed over the desalinator high-pressure pump (which shortly after died) the battery chargers and most of the pumps. I plan to place a Plexiglas barrier protecting the battery chargers similar to that which will be used to protect Kamela Harris tonight from the vice-president Corona virus spary ;). 

  Also, by connecting the inverter 220V output to an outlet identical to those used by the two shore power outlets, it will be connected to all the 220V devices that are run with shore power and generator without having to modify any of the AC wirings of the boat and will use the RCD of the "white box".  I find it unnecessary to add a second RCD at the outlet of the inverter for the same reason that there is no RCD between the shore power and the "white box".  With this approach, I can manually change the plug between any of the two shore power outlets (as currently possible) or the inverter outlet that will be installed in that box.  In addition, while I was charging the current AGM batteries with shore power and monitoring the current into the batteries, I turned on the generator and observed that the charging current went temporarily to zero before it restarted with the generator. This means that the relay switch does exactly what your 3 position switch.  It disconnects the power input to the "white box" before turning on the power from the generator.   Obviously, I will not be using the battery chargers while the plug is connected to the inverter outlet (the new outlet I plan to add to the "white box") but I could be using any of the other devices inadvertently.  In case I want to charge the batteries with the generator I will be turning off the inverter before I turn on the generator. and then turn on the battery chargers.  This will prevent that I inadvertently leave the battery chargers running on inverter power after I turn off the generator by forcing me to make sure the battery chargers are off any time I turn on the inverter.

I want to clarify that I will be installing an inverter and NOT and inverter charger which brings other complications to the problem, particularly when using shore power with 60 Hz.

Still, I what to know what people have done with the AC grounding of the inverter. (leave it disconnected or connected to the battery negative cable

I will be adding pix once I have concluded and tested the new system

Jose Venegas
Ipanema SM 278

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