Alright!

Some days are bigger than others around here. Some are milestones. Yesterday was one of those. The snow finally melted enough for me to pull the heavy duty extension cord up from its usual home linking the generator to the pump and set it up to hook the solar electric system directly to the pump. Looking at all the amperage's it seemed like it should work and we hoped it would work, but until you plug in and water starts rushing into the water barrels, you don't really KNOW it will work.

Well, it worked! This is huge for us. We have water without running the generator. By running wire under the paddock and into the barn from the well house, we can move water from the well to the supply barrels at the flip of a switch. The final piece of the puzzle is in place and it all works! Our water supply is gravity fed instead of pressurized. We have storage barrels upstairs and over sized supply lines from there down to the faucets.

This test with the heavy extension cord was critical. We didn't want to bury an expensive electrical line from the barn through the paddock and over to the well house and then discover that the solar electric system just shuts down under that kind of load. It is a 1500 watt system and has a very small serge component. When motors start they usually cause a surge of power that can be twice to three times their normal running wattage. A half horse pump runs at around 8 amps. (stick with me here, I am going to do some math. There is no test at end and I am going to give you the answer.) Watts= volts x amps. So the 110volts x 8 amps = 880 watts. So the motor should run on the system after the initial surge. Would the surge cause the system to overload? That was the question. The answer we now know, is NO.

We paid extra to get the "soft start pump" which is supposed to not have a large start up surge. We asked when we bought the pump, what the surge might actually be, and the salesman at the plumbing supply company, said it should not draw over ll amps under any conditions. Still, salesmen are not electrical engineers and they are not spending their money. If the system overloads, he will not be starting a generator for the rest of his life every time the water barrels need filling. Let's do some more math, 110 volts x 11 amps 1,210 watts. The system should start the pump and run it.

Well, the "test" worked, the math and the salesman were evidently correct, and the system works. We are ecstatic. Yes, ha ha ha the system works. It takes exactly 5 minutes of running the pump to supply three days of water at winter conditions. In the summer, the water needs will vary greatly and we will need to water the garden. Still, an hour of pump running will supply about 600 gallons of water. I am convinced that our system could do this. If the sun is out and it is clear, a third of the power would be coming from the sun directly. It is not unusual to get over three hundred watts from the panels.
The four batteries are rated at 100 amp hours each. You can use 25% of this or 100 amp hours before you need to recharge. In theory, we will use about 880 watts divided by the 24volts of the batteries = 37 amp hours roughly for every hour of water we pump. There is some system inefficiency, but on sunny days (when you would need more water), we will be able to supply most of it by solar electric system.

If you have read this far, bless you. The point of all this is, plugging in the pump to the solar electric system and having it work was a very, very big deal.