Marine Application Generators

Discussion in 'The Projects Forum' started by Ron Patterson, Feb 26, 2015.

  1. Ron Patterson

    Thread Starter New Member

    Feb 26, 2015
    I have come across an old stock Fabco Powermite 110 and regulator pretty cheap and thinking of using it on my sailboat powered by a 50 HP Westerbeke Diesel and get rid of the old 4KW genset to save weight. We use 110 mostly only when docked or running in the ICW and less so when sailing and anchoring out. I would like to be able to run our A/C, which is 10K BTU and starts on about 1900 watts and runs on about 1100 watts when really hot outside. I can put a start kit on it that will lower the start to ~15000 watts

    The issue is the Fabco hits 60 cycles about 1200 RPM. The regulator keeps the voltage ~110 and has an inverter circuit to hold the power at lower RPM to idle. The only way to deal with the cycles issue during running that I can think of is to convert it to 12Volts and invert it back to 110.

    Since this is essentially the same way they do it on inverter generators like the EU2000 from Honda, I thought it may be worth doing. I understand and my PTO on the engine will be pulling ~6 HP. That is OK.


    1. Since it is easy to find RV Converters around 70 amps that are fully protected for cheap, can you run two or three in parallel with short 12V leads to an Inverter to utilize the power required when needed for the A/C? Note that starting power can be absorbed by the batteries since a short duration. The Powermite provides 2500 watts continous. Do I need to stay away from auto-switching power supplies - are they driven by cycles and not voltage?

    2. I was looking at the schematic for the Honda EU3000i (which I happen to have an old one that Ethanol has taken it's toll on.), and it appears that the generator on it has three windings. One for 12V 10a (to charge the internal batter and...? And two others that are at least 110. I am not sure and can't test until I can take apart the generator and test the output. Does anyone know, and would it be possible to use the converter/inverter from the Honda?

    3. I was told that if I want large voltage loads, it is better to have an A/C generator even if converting and inverting lose 10-20% efficiency. Is this true and why?

    4. One thought is to also replace my current 12V alternator with this unit as my 110V chargers are better on the AGM batteries?
  2. debe

    Well-Known Member

    Sep 21, 2010
    All the inverter generators use a 3 phase high freq head for the main voltage, & there is a sub 12v ac winding to feed the electronics in the inverter. The 110 3pase windings will be mutch higher than 110V ac. The inverter will need 3 phase to feed it.
  3. Ron Patterson

    Thread Starter New Member

    Feb 26, 2015
    That would make sense.