Solar Size

[CampDavid]

Guys, I am new to the forum and know little about solar panels.

I am thinking of installing a solar panel or panels on my Beneteau Oceanis 400. Currently I have 4 6-volt golf carts, total amp hrs 464, capacity. We cruise georgian bay. Have a Honda 2000, Balmar 100 amp and three stage regulator.

My Link 10 shows that I use about 75 to 90 amp hours a day at anchor, mostly the Adler Barbor Cold Machine or should I say Cool Machine (LOL).

My plan is to mount a panel on the cross bar btween the two davits or high at the aft of the Bimini.

Can anybody suggest a good make of panel and size of panel to use? Are two 80 watt better than one 160 watt? Any good suppliers to purchase from? I am surprised at the weight of the panels, does this become an issue if mounted on the bimini, I am not sure it can take 50 lbs?

Many thanks as this is my first post.

Fletch
Camp David

[roverhi]

I ran my batteries down on the trip to Hawaii. Have 2 130 watt Kyocera panels but they didn't keep up with my minimal usage in mostly overcast conditions. I use less than 30 amps a day and had drained the batteries down to about 50% After 12 days. Even another 3 1/2 days of mostly sunny weather didn't get the batteries up to full charge. Overcast cuts the production down by at least 80% and even a slight haze will halve the output. Max generation is between 10 and 2, believe that would be 11-3 with daylight savings. Before and after that, production falls off significantly. You may do better being so near the Polar Bear's perpetual daylight in summer but doubt it. Boat heel can seriously affect, either positive and negative, output while sailing. Also boat orientation to the sun can have an effect. On my downwind slide to Hawaii, I was pretty much sailing into the afternoon sun so had very little production after 3pm because of shading by the sails.

Unless you have an overwhelming desire to be PC with the 'Green' crowd, a single panel isn't going to do you much good for the expense. There are some very large panels that put out 200 watts plus but they take up a good deal of real estate. If you are going to use 130 watt panels, would think you'd need at least 4 panels to meet your needs and two to have any significant effect.

FWIW, We've lived on solar power for more than 10 years and my boat is normally totally soiar self sufficient. You can never have too many panels.

[GeoPowers]

Fletch,

As far as panel sizing goes, I attached a spreadsheet I created a while back to figure out electrical consumption. It also has some tools to figure up amps (and amp hours/day) when you know the watts and voltage for a given solar panel. It works for getting to the math behind what you really need as far as power supply/demand goes..

There are lots of brands out there- I often browse sunelec.com as a source to see where prices are.

Can't wait to get ours after we move to the East Coast!

Frank

[barnakiel]

Sunpower - more Watts from square ft than Kyocera, Siemens or BP.

Here, as shown in a German supplier, probably way cheaper if you find a US source:

http://www.svb.de/out/1/html/0/catalog/s_101.pdf

You can mate them with a Votronic MPPT regulator.

Good idea to make the rack adjustable, so that you can angle your panels towards the sun - huge gains in Amps!

Cheers,
b.