solar water pumping

SystemSystem Posts: 2,511 admin
New to the forum with lots of questions. I would like to know if you think that one of those small 12v pumps used in fishing boats could be used to keep water pumped from a cistern at the back of the house to a holding tank on the roof used in heating water by the sun? This would not be a distance of over 10 to 12ft. and when the cistern is full would be alot less than that and only 3 ft. when the cistern is full. I know that they do not pump a large amount of water, but if it would keep the tank filled this would be a big help. Thanks


  • mike95490mike95490 Solar Expert Posts: 9,047 ✭✭✭✭✭
    Re: solar water pumping

    pumps are usually rated by Lift and Flow, and as the lift approaches the maximum, the flow slows way down. Beware of using a bait pump for household or heated water. (if the rooftop heater backfed into the pump will it melt into a glob of useless plastic ?)
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  • System2System2 Posts: 6,290 admin
    Re: solar water pumping

    I plan to have a thermosyphon type system that I could fill up the tank when needed from the ground and not have to go on the roof to fill each time. I had planned to have an over flow and cut the pump off when the tank was filled, but I can see probably where this would disrupt the thermosyphoning effect. I had not planned on hot water entering back through the pump and going down back into the cistern. We have a large sytem that I made a few years ago on a piece of black painted metal and copper tubeing covered with glass that has reached to boiling temps., but used an AC pump to circulate into a tank of talapia in the green house to keep them warm. We plan to build a small home in the south pacific that has no running water on the property at the moment so a cistern will be needed and the electricity there is 230v and not to dependable so I am trying to come up with a way to go solar as much as possible. Alot of the time rain water would keep the tank filled, but I am sure there will many times that it will have to be filled another way. Any other ideas?
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