[C320-list] Solar panels and shading

[Warren Updike]

I don't have a solar panel so I'm lurking on this thread. What you call the "hatch garage cover" I assume is the sea cover. I did find the imbedded wires where they exit in the battery locker under the settee. In my manual, there are several diagrams re. installing a solar panel on/in place of the sea hood. To access the wiring channel, there are dimensions shown on the diagram of where to drill to find the wires. You drill down into the channel a distance back from the fwd edge; but, I couldn't read the numbers. Also, "earlier" models the channel is port side, later models on stbd side. As ours is #62, not sure what is meant by "older models." 

Solar panels are rated in a laboratory not in the real world. Not only shading, but the angle of the sun affects efficiency. Virtually no solar panel on a boat is going to deliver rated capacity. At least, not all day. Enough people are using them with mostly satisfaction, so the loss of power can't be a major hit. 

We have an upgraded alternator and battery monitor. No other source away from the dock. With the refer on 24 hrs, we will use about 50A from the time we drop anchor till we pull it. Once, we had to sit a week on a mooring due to weather. We ran the engine about 1-2 hrs in am, and that was enough to carry us over. (We have all LED lights on the boat.)

Just saying,
Warren and Pattie Updike
1994 C320 "Warr de Mar" #62
Middle River, Chesapeake Bay

 

-----Original Message-----
From: Graeme Clark [mailto:cg at skyflyer.co.uk] 
Sent: Monday, January 29, 2018 5:22 AM
To: Catalina list
Subject: [C320-list] Solar panels and shading

I’m about to buy a solar panel to mount on the hatch garage cover, forward of the traveller. ( I don't have a bimini nor an arch so no other choice really).

I think it has to be the flexible type as I have noticed that occasionally the mainsheet block can drop forward onto this space, if the mainsheet goes slack, and I suspect that would soon crack a ‘hard’ panel.

At first glance the ‘garage’ has a large area but of course the forward corners of it are encroached by the halyards and other control lines and the rear by the traveller control lines.

I have read that even a small amount of shading can hugely reduce the amount of power from  panel - in other words 10% shading will give a 50-60% reduction in power, not a 10% reduction in power.

So I am considering a smaller panel that is completely unobstructed.

BUT someone else has said that the flexible panels are more tolerant to the shading problem, more like a 10% shading giving  a 20% reduction in power.

I’m confused -  do i go for the biggest panel I can fit or the biggest I can fit into an unshaded area?

Lots of conflicting advice about this on the internet, so i thought I’d ask if anyone on the list has this particular configuration and if so what your experience has been

Thanks

Graeme

#366, 1996, England