Solar system recommendation

[AllanS]

Hi, my 8kW generator just died at the beginning of the season. I’ll deal with replacing it (maybe) next off-season. In the meantime, I am thinking of generating the AC power that I need away from the dock using a solar system. We plan to stay at marinas this year so at night we’ll have access to shore power. I only need to run a fridge and some fans (about 10 Amps) while away from the dock so I am leaning towards a couple solar panels on the aft-cabin, a controller, battery bank, and inverter that I tie into the AC side of my panel. (I do have a Honda generator that would do the job, but it is noisy, needs gas, and my wife doesn’t want gas on board).
Can someone recommend a good set of solar components to do what I am describing? Is it best to use a separate battery bank than the 4 house batteries? What systems would allow me to monitor input, output and capacity?

 

[JHornsby3]

When I had RV's, we used solar all the time. We picked up a good setup made by Coleman(Sunforce) that would charge up the two large gel cell batteries during the day. And it would provide enough power to run a TV and dvd player as well as the water system, lights, furnace and fridge all night long. And when I say water system, I'm talking about a family of four taking showers, meal prep and dishes washed before bed.

So a couple or even one large panel mounted should do you good for the house batts. The controller I had was a 200 watt controller and three panels that totaled 100 watts. Those would charge the two batts in about 6 hours of day light.

For a system that is temp at best, it might be best to not go out and spend a winning lotto ticket to fund this. Use the money to repair the gennie.

 

[GnrlPatton]

I installed 2x 100w flexible panels, a solar charge controller and an inverter a few years ago. My goal was to be able to be on the hook without needing to run my genset a lot. I would say that I've been only marginally happy with it. Unless it's an extremely sunny day, and the sun is directly overhead, my charging capacity is less than I had hoped for, and I'm still needing to run the genset more than desired. I'm not sure where you boat, and if you will have those kinds of conditions or not.

I would suggest what John said, and save the money to get the genset repaired, or invest in higher capacity house batteries (I'm now looking at adding LiFePo4 Lithium batteries to give me more capacity, but that comes with it's own set of problems to deal with).

If you do decide on solar, I'm happy to explain what I did, it's relatively straightforward if you have worked with electricity before.

-Kevin

 

[AllanS]

Since I am charging my 4 house batteries from the engine alternators while I’m cruising, could I not just draw the power from the house batteries to power a 12v/120v inverter and get my 10A of alternating current to run the fridge and accessories that way, or is this risky? How much power do alternators produce? That is, do I need a solar power at all?

 

[JHornsby3]

Does your fridge not run on 12v as well?

I know truck drivers that run dorm style fridges and other kitchen appliances off of a invertor. But they take a very large invertor and still requires them to fire up the truck in the middle of the night when alarms go off. That or their APU starts and charges the batteries. Sounds like your gonna need to add batteries or go with a larger solar array to do what your wanting. I have known folks that would spend thousands on solar power. I would say you need to weigh the costs of what your wanting verses the gennie repair.

 

[jmauld]

How much time are you away from the dock and are your engines powered the entire time?

What is the current draw of your fridge while in DC mode?

Also, can you swap your 120v fans for 12v fans?

I don’t know what alternators you have, but you could be producing 150-200A at 12v DC, assuming two engines and two high output alternators.

just for a reference point, if you wanted to supply a 10A load at 120v for 10 hrs you’ll need 12000kw of power. That would be three of these guys: https://dakotalithium.com/product/dakota-lithium-48v-96ah-deep-cycle-lifepo4-marine-battery/

or 1500w of solar panels.

I think you could do what you’re looking for with a larger house bank (maybe 4 12v, 100ah lithium batteries) that you can charge overnight, then use your alternators to recharge those batteries as you drain them. Solar panels could supplement this, but wouldn’t be needed.