Question about putting 12v solar pump into well casing for slow feed to a remote tank

Options
Hi everyone,

We have an interesting situation. We live on a fairly steep hill and the well is at the bottom, while our house is at the top. This resulted in 2 electric meters with the meter fees for both services being kind of pricey.

Here's the nuts and bolts of our issue. Currently, we have a 1hp well pump 22ov activated off a microswitch that is powered in our home utility room and mounted on the pressure tank. The well is about 400 feet down the hill with a 50-60' lift. Currently, we just run the 220v pump and do not use our 550 gallon tank other than for storing water for power outages.

What we want to do is place our 12v solar pump (with panels and no battery bank) into the well casing above the 220v pump and slowly fill the storage tank and then run the water from the storage tank through our pressure tank to use in barns, home, etc. We will need to put a float activator into the storage tank and attach that to the microswitch that should then tell the solar pump to run.

I've previously done the math and the Shurflo pump will fill the tank slowly with the distance and head. I think it was about 2 gallons per minute at max possible rate.

The main question I have is whether to hook the solar pump line into the existent water line using the same check valve that is in the existent water line? Or should we plumb in another line with it's own check valve that enters the existent water line after the check valve for the 220 pump? Also, do you think we can run it off panels alone, or do we need to put in a battery bank? Our usage will be fine with the 500 gallon tank. We have good sun exposure and are located in the Missouri Ozarks. We can put in a battery bank if needed, just want to keep costs down as much as possible.

We want to leave the 220v pump in the well in case something happens with the solar and then we can power the 220v pump off the gas generator.

The flow rate on the well is 12 gallons per minute, so we have never had any issue with running it low even on the 220v.There is no way for the solar pump to run the well out with the replacement rate.

Thanks for your thoughts! It's already an ususual set up, and changing to solar will make it even more unusual.