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?
St. Paul, MN
S/V Sea Dog
Apostle Islands Lake Superior
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.