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Anyone convert to inverter-based system?

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    Anyone convert to inverter-based system?

    We plan to convert our boat to inverter-based next year. Basically, all 120V AC loads will be fed from a pair of "stacked" (meaning one will be on and one will remain idle unless loads exceed the capacity of one inverter and then the idle inverter will automatically turn on) 3000 watt pure since wave inverters that will only be connected to the house batteries and the genset. Shore power will connect solely to flexible input voltage/frequency/current battery chargers.

    The concept is to allow the boat to be powered anywhere in the world, by any voltage between 100 and 250VAC 50/60Hz and 15, 30 or 50 amps. It also isolates the boat AC power form the shore power like an isolation transformer. Peak loads in excess of what the shore power can provide will fed by the house batteries. When the loads drop the chargers will make up the lost power in the batteries.In case this sounds funky please understand that even a lowly 120V 15amp circuit can provide 43.2 kilowatt hours a day, which is almost twice as much as I use in my house.

    Anyway, anyone else done this?


    i use an inverter/charger/paralleling pure sine wave unit. Shore, generator and batteries are connected to the unit. The unit will pass through up to the limit of the shore power source. If more power is needed it will pull the power from the batteries to pass on additional amperage. When the load reduces it will divert the extra capacity back into the batteries. Excessive capacity could be sent back up the line to shore if I choose, i’ve Just never chosen to do that. The system will also start the generator should the battery back fall below 12 v.

    i see what you are doing and i’m Going to have to think about it. On the surface it is clever. I feel the system is going to be very inefficient but that might be an acceptable trade off if you routinely travel between 120v and 250v countries.
    Seattle, WA
    Ocean Alexander 54


      It sounds like a good idea, especially if as prevously mentioned you transit between locations with diggering shore power standards.

      where are we right now​​​​​​???​


        I must confess I got the idea directly from Nigel Calder, it's not something I cam up with on my own.

        Regarding efficiency, it's really only an issue on shore power where efficiency is not a big concern. At anchor, my boat will be mostly powered by 1000ish watts of solar I'll be installing. When the genset is running, it will bypass the inverters. Hoping that with all that solar I can keep the genset use to less than 5 hours a week, if we are not running the main engines. If we run the main engines much, we will rarely need the genset. Our boat ventilates well and has canvas shades and awnings on the outside and blinds on the inside that will help keep the sun from heating up the interior on hot days.

        One Idea I did come up with is to anchor facing due north, when possible, and use a stern anchor in addition to the main anchor (when safe to do so) to keep the boat facing due north. This will dramatically reduce the solar load on the cabin and ensure the solar panels (which will be aft of the flybridge) remain unshaded by the boat all day.


          I use a Magnum MS-PAE 48v inverter/charger. I like the 48v because the cabling can be smaller and batteries can be further away where the weight can do some good. When I got my current boat, a generator had to run when cruising. By adding a big 48v alternator I eliminated the need for a generator when the mains are running. Thinking about a canopy with solar for times I'm anchored. Inverter will start a generator if the bank it's on gets low.


            I'm thinking of eventually adding a 48 volt lithium battery connected to my solar panels and then have that charge the 12V house bank though a DC to DC charger. That way I could mix battery voltage/technology types with ease, and put the lithium battery wherever I want to. This is also a nice way to build a bigger system in affordable stages. I've only got room for about 600 AH of 12V house battery. A 100

            The system would prioritize keeping the 12V lead acid batteries fully changed and only stop charging them when the lithium battery drops below 20% With 1000 watts of solar, I'm not sure I'll really need to charge the lithium battery with anything but the solar, but I'll put a 48V battery charger on the shore power/and genset just the same. May not bother with a 48V alternator.


              If you have a 48v inverter system, the nice thing about running a 48v alternator is not needing a generator any time the mains are running. Also it doesn't matter if the AC is a light load. Long runs with a light load can glaze the cylinders on most yacht generators. My boat is almost all 120/240v. Only bilge pumps, electronics and emergency lights are DC. I get a lot better choice in lights, switches, smaller wiring and no big, short life DC motors.


                I'm still building Aquatica, but it will have a 10,000 watt inverter on the primary battery bank, and a smaller unit for my secondary bank. The primary bank will be 12 deep cycle golf cart batteries hooked in series. The secondary bank is only 4 batteries.

                The primary bank will handle all major loads as the boat's power system will be generating enough power to run two and a half households with a total load usage for roughly ten people, though it will just be me in the boat.

                The secondary bank will hook to solar panels and a wind turbine. The primary will be a magnetic powered generator which are very easy to build or set up.

                The secondary or back up bank will be used mostly for lights and light loads such as marine radio, GPS, etc. The primary will run my bilge pumps, washer/drier, fridge, microwave, TV, computer, convection oven, dehumidifier, air conditioning, fans, heater, water pump, tankless water heater, and my water jet propulsion system (also a simple electromagnetic system).

                Since the primary generator is magnetic powered I don't have to worry very much about maintenance or repairs. Once a month I will stop the generator, re-lubricate the shaft, and check that nothing needs attention. It's a very reliable system and the 10,000 watt inverter is extremely effective.