Comment: I have a 50 GPM pump well for 50 acres.

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I have a 50 GPM pump well for 50 acres.

I water about 40-50 trees by drip continually most of the year as it's been a dry year out here in CA. The well is 300' deep w/ a 5HP pump, I plumbed in 4 85 gallon pressure tanks to ensure the well runs at least 1-2 minutes before shutting off, and will double the life of the pump. If I were in your position i'd not even bother with going off-grid on the well if you have power on site. If you are living on the property you will want to have your water at your house all the time, especially with kids. My kids shower often enough it would drain the 85 gallon pressure tanks at night with showers if it was pure solar.

If you are set on the idea of using a straight well pump with no pressure tanks and primarily for irrigation of gardens, i'd go with a grundfos SQflex pump that can wire DC directly without any complexity. Today, you can buy canadian solar panels for about $.80 per watt and wire them in series to get 300V, reducing your DC wire cost. If your well head is 8" in diameter you might be able to run both a standard pump for household use on power and a separate pump for irrigation on solar that is independent. I am a bit of a prepper and I've purchased a 16KW generator for emerencies that is wired to a separate sub-panel and only turned on manually in a situation where power is out for a while to re-charge the pressure tanks and still flush toilets in the house. The solar stuff is expensive if you are trying to run it every day, and grundfos is the leader in solar pumps for remote irrigation of livestock and fields. These pumps will set you back $2-$3k and should last quite a while. The crap on eBay people sell as a DC solar pump and kit might last you a year with what you are trying to do, and if you run those basic pumps dry it's game over for the pump. The SQFlex has the ability to shutdown in a dry situation.

My advice here is to not overcomplicate this with inverters and make it very basic. If the water you pump out will not be used for drinking, let the solar charge a 1500 gallon above ground tank with a small 3-6GPM pump that requres a few hundred watts, then run a DC booster pump off of solar above-ground with a pressure switch. You'd be quite surprized the volume of water you will get even with 3-6GPM for basic gardening and irrigation if it runs all the time.

my $.02

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