The basic rule
of thumb is to have 1/3 your AH in battery
storage in solar AH. The problem is that some panels
are rated at higher voltages, and thus, your actual solar AH are less. My 45W panels
would be expected to put about almost 3W at full power, but are really around 2W. They are rated at 22V, not at 12V.
I have about 440 AH in house banks and 2X90W in panels and a 600W windmill. The starboard bank died after about 4 or 5 overcast days, and the only load was an unloaded inverter
. Could have started that period with some work that used some of the capacity. I always thought it was almost unlimited. These are brand new batteries.
So, I can say that the rule
of thumb is OK, but you have to monitor
your system and maybe use the wind generator
or fossil fuel generator
to top up the batteries if necessary.
My brother has something like over 5 kilowatts of solar on his house in Hawaii
. He is neutral to positive in his application.
One of my voyaging friends said, when people are aboard and it's overcast, and there's not much wind
blowing, we have to run the generator
Probably the main contibutor in the tradewinds is the windmill. At sea a watermill will do well. I have one but the internal magnets are cracked and I have to restore it. It dates from 1978.
This time of year, in the Florida Keys
, or in the Caribbean
, you might have those excellent conditions with generally strong winds, and good sunlight during the day. An optimum condition for power generation.