Quote:
Originally Posted by Ketchgould
I'm thinking of installing solar. If I get a small panel say 60 watt with 12 volt system the max amps per hour is 5. On Lake Superior in the summer do you think I'll actually average 50% of that for 8 hours a day?
Christian Gould
St. Paul, MN
S/V Sea Dog
Apostle Islands Lake Superior
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No, I don't think so.
12v is a misnomer. In order to charge a "12v"
battery, you need to be putting out more like 15v. In my case, 15.5v. A 60w panel is putting out less than 4A @15.5v and that would be under perfect conditions - an
MPPT controller, a solar
tracking mount, absolutely NO shading, etc.
Why such a small panel? I won't even pick up a drill and drill a hole for anything less than a 200w panel, the effort to mount it isn't even worth the small amount of
power they put out.
Price can't really be the issue, the last
panels I bought were 230w for $135. Most people spend $200 or more for a decent
MPPT controller, might as well spend a few $$ for the
panels and get 400w or more.
Aside from space considerations, there really is no such thing as too much solar
power. Did your
batteries get fully charged by 11am? Is that a problem? After all, a decent MPPT controller is also a 4 stage
battery charger, the good ones give you full control over bulk, float charge voltage, etc.
What if it's partly or totally cloudy for a day or 2? An "oversized" system is still going to be able to crank out some power under partly cloudy conditions, a system that's barely enough on sunny days is going to be nearly worthless when it's cloudy, and even worse if it gets shaded.