I am looking to move to a purely solar powered dc pool pump. I found a pump that meets my needs. It is 72VDC 900Watt pump. It is designed to run directly from the solar array. The description recommends 6 panels - 200watt@18v. The panels are hard to find with that configuration. In other forums, guidance is to provide 1200Watts but no mention of the volts. One even stated 12 panels - 100W@12V. I am not sure of the panel configuration, but thinking they would want 3 in series and 2 sets in parallel of 3 parallel. (54V)
Thoughts on if the wattage is more important than the voltage for these pumps or if I need to consider both?
I could wire these to have 6 in series and 2 sets in parallel to meet both needs. (72V)
I could wire these to have 4 in series and 3 sets in parallel to meet both needs. (48V)
this is where my knowledge seriously breaks down.
Thanks for the help.
DC motors will run at lower voltage than its ratings at lower speeds of course. So it is better to get a reciprocating pump. they will deliver regardless of speed. There are solar pump sets if you can get one you wont have problems with matching. My friend got a 1hp submersible pump set.
also try to avoid batteries. That's where your electricity saving goes. Centrifugal pumps needs certain speed to deliver. thus a set battery. Personally I wont go that route. piston/reciprocating pump will be my choice for solar driven. You wont need a battery for this
At that Voltage your looking at 12,5-ish amps. I don't know much about pools, does the pump need to run all day or can it also run parts of the day on a timer?
I recommend looking up a bubble pump. I have just started to read through 'Organic Pools diy manual' by David Butler. The bubble pump he uses is just a water pipe with a vertical portion (L-tube) that he inserts a air tube from an aquarium. Air mixed with water is less dense than water so it will exit the top. This will draw more water in the bottom of the L tube (through filter?). This should result in a huge savings in power because you are moving air instead of water. I am not familiar with pools, I just thought this might help.
"We will never be truly healthy, satisfied, or fulfilled if we live apart and alienated from the environment from which we evolved." -Stephen Kellert