Solar panels

[pepmyster]

Hi fellow Carver members! Ok, we have no choice now but to go the solar route due to the fact that anchoring with a mooring buoy in Parks Canada areas does not allow me to run the genny. So, need some input from the experienced people who have been there, done that. I basically what to keep the house batteries up to snuff. I don’t want to go the permanent route, looking for something that good easily go on my dash , something removable if not needed. Thanks guys!!!!

[km1125]

Really have to figure out how much load you have at "rest" and how often your bilge pump needs to run at "worst case". Worst cases meaning some water got into the bilge and you need to get it out, or you have a SMALL continuous leak and need to periodically empty before it gets to overwhelm things.

If you only need to worry about topping off the batteries and the bilge pump just runs sporadically, you could probably get by with a 100w panel. That's probably what I'd use as a minimum. If I had any additional loads that I'd need to run (like a refrigerator?) then I'd scale up from there.

[Viper]

Check out the flexible panels. You can roll them up so they're easier to store. The size is going to be dictated by the amount of output you need and your wallet. High quality units are more efficient and will deliver more energy in a smaller cell so the overall footprint for equal output will be smaller but they'll be more expensive.

[Midnightsun]

The only real draw at anchor is the fridge so you are looking at around a 4.4a draw lets say 50% of the time or could be much more if you keep stuffing it with warm beer. I would recommend a minimum of 100w just to help. I have 300w and it suits my needs well. That being said a larger bank that needs charging less often is sometimes a welcome addition. What size house bank do you have now?

Unfortunately solar panels do not like any shade whatsoever so dash mounting is not viable except for bragging rights that you have solar. The best place for a temp panel would be the front deck in the open air free from shadows. Flexible panels would be the best route, google is your friend.

Just a shadow from an antenna even though it may be an inch wide can shut down the entire output. See this.

This would be my choice for something you can setup and remove as required. https://www.amazon.com/ACOPOWER-UV11007GD-Foldable-Generator-Controller/dp/B01MU4PGLQ

[pepmyster]

Running 4 cat 27 batteries with 200 reserve

[bud37]

Pep.....do you know what the total amp/hours are for your battery bank...that number would help the calculation I think.That is the easiest way to calculate recharging ...... Imo.

Edit....is the 200 you have there total bank reserve capacity or Ahr capacity......reserve and Ahr are very difficult to equate.

I could see your use as others have noted at around 90 ahr for the fridge , toilet and some lights and that is very conservative for a 24 hr period and you have a very nice boat......now to put it back....100w solar may give you 5 Ahr for 5 hours= 25 ahr on a perfect day.

Something to consider.....personally I don't think this will work with a small temporary panel.......just my opinion, I have never tried it but can do the math and have considered this before, may be fine if all you are doing is staying for one day thereabouts then all the recharging can be done on the trip away. For more than that the math doesn't work imo.....

[pepmyster]

200 reserve. 90@ 20 amp hours.

[pepmyster]

Source of the post 200 reserve. 90@ 20 amp hours.

[km1125]

Your first exercise is to figure out how much power you draw when sitting just on batteries. The best way to do this would be a battery monitor, but you could calculate it and come close if you know ALL the stuff that needs to stay running. If the boat is vacant, then it should be minimal stuff, like fridge and bilge pumps.

Is there anything else that needs to run? Do you really need to run the fridge?

The battery capacity is really only going to matter to make sure you have enough storage for when there's no sun, like overnight or maybe subsequent overcast days.

My fridge takes about 10A at 13vDC to run, but it only runs about 1/2 the time. So it averages 5A for 24hours, or 120 amp-hours. At 13vDC, that's 1560 watt-hours. If you have about 6 hours or GOOD light each day, then you'd need a MINIMUM of a 260W panel to just run the fridge. You'd have to add some capacity because of efficiencies in recharging the batteries, so you'd really need about 10% more than that (almost 300W panel)

If you have other things that need power, you can add them to that calculation.

[pepmyster]

I don't think that I'm gonna get away from the 300w system, like Hans has. During the Toronto boat show, I will be looking at the suppliers that will be there, and , doing some research during the winter months.