I am considering inverting a whole house boat. This is in America and for shore power I have 2 50amp 240/120 cords. It has a 22.5 KW genset. The breaker panel is split in half, one half for each cord and a transfer switch for genset power to both halfs. There is a 240volt water cooled 5 ton AC unit and a couple other 240 loads. I was thinking of using four 120volt Qaurto’s on two can bus’s. I can fit 15KW of solar panels on a flat roof and was thinking of between 2000-3000 amp hours of batteries. The Goal is to run the Genset during the day and get the batteries up to @90% then be able to shut down the genset for night time. I am well aware of the costs. I am interested in any comments or ideas the community might have. Thank You
Cool project. The water cooled AC sounds interesting too.
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
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Hi Burl,
In what state do you float your boat? I’m asking to get a sense of your daily PV energy collection vs outside temperatures. Do you live on the boat full time or just occasionally? Do you need to use bubblers while at dock in the winter or is that not a concern where your boat is? I’ll assume somewhere warm in the SE.
In the dead of winter, you will get approximately 2.5 hours of solar irradiance per day and about 5.6 hours in mid summer. A 15kWp array will produce, on average, about 37kWh of energy per day in winter and 84kWh in the summer. You may not even need your generator in the summer on most days, but that depends on where you live. If it’s warm in the winter but not so warm that you need air conditioning, you might not use your generator much in the winter, either. Knowing your loads and energy usage per day would help.
You could build two smaller systems with separate battery banks and GX devices and each system would have one shore power as a source and power half the AC breakers. Or, have a single battery bank and run two different VE.Bus inverter groups (as you mentioned) and send the output of each to one side of the breaker panel. You might also just run all four Quattros as a single inverter group and split the AC output across both breaker panels. What size Quattros were you thinking? 5kVA or 10kVA? Four 5kVA would likely be plenty of power. In this scenario, only use one shore power connection to feed the inputs of all four inverters. If you need more power than the shore power input can provide (12kW non-continuous load), the inverters can supply the rest from battery. 12kW peak shore power (50x240) can provide 12kW ÷ 1.25 =9.6 kW. 9.6kW x 24 hours (if docked) is 230kWh of energy for charging batteries and running loads.
What I’m suggesting is: if you invert the entire boat, you don’t need two shore power inputs. You can simplify the system a bit by using one shore power input and running the generator into one of the inputs across all four inverters. This is typically how we deal with larger boats with multiple shore power connections if we’re setting up a system that can run the entire boat from inverters + battery.
Hopefully you have a good Victron dealer experienced with marine systems near you. You can check here: https://www.victronenergy.com/where-to-buy They can guide you and collaborate on the system design. This forum is not meant for system design, but rather for specific questions.