I do not recommend a CSV for most solar powered systems. A CSV cannot be used with solar pumps that have a helical or spiral shaft, or any type of piston, rotary gear, or other positive displacement type pumps. A CSV can be used with any pump that has a regular centrifugal impeller. However, you will get the most gallons produced by the least amount of amps by letting the pump run at its maximum flow rate whenever possible.
When using solar or batteries, water stored in a pressure tank is just as good or better than amps stored in the batteries. Because an 80 gallon size pressure tank only holds about 25 gallons of water, you might even want to consider 2 pressure tanks. This would help prevent cycling of the pump and would leave lots of water stored under pressure and ready to be used. In this way, when your pump is running, it is always supplying the most water it can produce with the least amount of energy. The more water you can store in a pressure tank, the fewer amps your batteries will have to store.
One trick you can use is to top off the pressure tanks before you run out of sunlight. Then let the batteries recharge with the last of the sun. You can push the plate on the pressure switch to manually start the pump and top off the pressure tank(s). In this way you will have full pressure tanks and full batteries before it gets dark. Storing water in the tank this way is as good as having extra batteries.
