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would it be feasible to design and build a off grid soler system that had several stand alone smaller systems. Like one for lighting, one to run the refigerator one to run a fan ect.
Bevers, Don't forget about water pumping. I don't know how you get your water, but it is a factor I frequently forget to add into my calculations. Most DC deep well pumps seem to use around 150 watts an hour for 60 gph rate. So if you use 120 GPD per person per household that averages to 300 watts a day per person for electricity. This is off the top of my head and I welcome any corrections.
My pump pulls about 10 amps at 240v or 2400 watts for 1.5 hours per day in the summer, when pumping for the garden. That is why I need the bigger system. The smaller pump would still have the same horsepower requirement, but just run for more time. I already had the pump 320 feet down the well when I decided to go solar. I like having plenty of power so I can weld and run my shop - band saw, air compressor, etc. Horsepower requirements change a lot and go a lot higher on a deep well. The Grundfos SQ Flex is likely one of the most efficient but the numbers should work out similar to mine I think. We use around 600 gallons per day or more for the garden in the summer.
That made my head hurt Beavers. Thanks.
Did anyone notice the oddity?
Looks like only one battery terminal in the T105 pic.
....and this controller: ........
Quote from: OlJarhead on December 01, 2009, 03:24:43 PM....and this controller: ........ That controller is not suited to that panel. The panel has a maximum power current rating of 4.71 amps. The charge controller is rated at "4A maximum input charging current". The place to start designing any system is to start with what the daily load total will be. Do that before jumping at parts. Make a list of all the DC items you want to use. Get the power ratings on the lamps or whatever. Multiply the DC wattage of each unit by the number of hours of expected use. Be honest. Total that up to get the DC watt hours for the DC total.Make another list of any AC loads you wish to run. A Kill-A-Watt meter is handy for determining how much power is being used by the various AC powered items. Multiply the AC wattage of each unit by the number of hours of expected use. Be honest. Total that up to get the AC watt hours for the AC total.Then come back with the list. With those numbers the battery capacity required to run one, two or three days can be calculated. With that known the PV power required can be calculated. You also need to know expected number of hours of usable sunshine. That changes summer to winter so you need to decide where are going to aim for. Or go here and use one of the calculators. I don't like to just say, here, do this or use this and everything will be fine as your deiniation of "average" or "normal" can vary from mine. But I'll be happy to help sort it out.