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Forum Index : Solar : Solar pump build.
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Some time ago I built a hydraulic ram to pump water from my creek, the water is used to keep some trees alive, water the garden, wash the car, etc. You can read about the pump here. The pump has been working well all year, but a few days ago the creek stopped flowing, and hydraulic rams need a flowing source of water to power them. A few weeks ago, knowing the creek would stop flowing soon, I started on a new project, a solar pump. The requirement was the solar pump would supply as much water as the ram, about 500 litres per day, and it had to be a cheap build. The pump is a little Flojet pump, 4 litres per minutes, over 30 psi, and draws about 1.8 amps. These are dirt cheap, you find them on ebay for around $30. For the solar panel I bought a 20 watt panel from Jaycar, along with a few components, including a PicAxe 08M chip. I had a 12v7Ah gell cell and box to mount it all in. The PicAxe is configured to monitor battery voltage and solar panel voltage. If the battery voltage is good, it will cycle the pump, 10 seconds on, 20 seconds off. I cycle the pump because its rated for intermittent use, and the solar panel can supply 1.2 amps, the pump draws 1.8 amps, so I need to draw less than the solar panel can supply, to keep the battery charged. Also my water source is a living ecosystem, a soak fed pond with fish and other wildlife, so I don't want to take too much water away from it. If the battery voltage goes much over 14 volts, the PicAxe switches in a 10ohm 40 watt dump load. Typically this happen in the middle of the day. I gone for a dump controller because its a simpler circuit that used components I had in my junk pile. When the battery drops below 12.5volts, and the solar panel is no longer supplying current ( low sun ), the controller goes into night mode, and waits for the sun to come up and battery voltage to reach over 13 volts. I'm using a coke bottle as a pressure vessel after the pump, makes it easier for the pump to start, there's a big column of water to get moving when it cuts in. In the creek is another coke bottle, with lots of little holes and a few rocks inside to keep is under water. It works well, and I have another inline filter just before the pump, its remained clean after a few days running. The solar pump has been running for a few days now, and is working well. When the creek starts flowing again I'll keep this pump working in conjunction with the ram pump, so I'll get over 1000 litres per day, using old and new technology, and for free. 
The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| paceman Guru  Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
Looks like a good little system Glenn. Do you have any sort of control on the cell output to the battery or is it just straight in - do you have a schematic for the overall system? I don't have a reason to build this up but I know someone who probably does. I was just checking the 20W panel prices - Jaycar have their Powertech one at $80 and Rockby have their Solarking one at $55. Greg |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Greg I'll draw up a circuit and post the PicAxe code in a few days, just want to make sure it works OK first. The solar cell is connected to the battery via a diode. A MOSFET, driven by the PWM output of the PicAxe, switches in the dump load. At this time I'm just switching the dump load in and out to keep the battery under 14 odd volts, but I will play around with some PWM later, I was thinking of adding a little windmill to the system so it can run at night, and the PWM will be needed then, along with a lower resistance dump load. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
OK thanks. Don't keep it too warm around the dump load at night - with the mill of course - the mice or brownies might get to like it! |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
It would seem a perfect little project to just build a water windmill to pump water. 
It could be as simple as a crank shaft lifting a plastic pipe up and down with a foot valve (check valve) on the bottom.
Making power to drive a pump seems not as efficent as just pumping water. Lower rpm, higher torque, works in low wind conditions, little fancy design work needed, etc...... I have even seen two twisted sheets of corrogated iron used as blades on water pumping. I think there is scope for Glenn to develope a wind water pumper to add to his mantle of Backshed developments. (be a simple fun project me thinks) Pete. Sometimes it just works |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Having built a few pumps from scratch, or replacing the cups in the big pump for the farm windmill, I can tell you its much easier to use a $30 electric pump from ebay. And its a lot easier to move energy through wires than a drive shaft, the pump is down near the pond, so it doesn't have to suck any more than a meter. It can lift more but the closer to the water level the better/easier it is for the pump. The controller is up on the bank, and I would put a windmill about 10 meters away on a fence line. Electricity does have advantages when it comes to ease of locating the individual bits. Some months ago I did start on a savonius windmill using a cut up 44 gallon drum to pump water as you suggested, but the pump would have been about 4 meters above the water line. It would work, but been a bitch to prime and any air leaks would have stopped it pumping. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
I was thinking of trying to use one of the 12 volt pumps out of a old camper to pump water out of our main well if the grid should go down. I was wondering how far one of these units will lift water? I might have to set up a primer and a check valve.? Nothing fancy just something to keep from having to carry water to the stool& and water the chickens etc. Isaiah URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Glen I'm with Pete on this one. Here's a Link I posted here somewhere back in the day. It shows a floating "oscillating" windmill pumping water; pretty clever as well as simple. Maybe it would work for you as an alternative to the solar-pump thingy when the weather is overcast. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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Don B Senior Member  Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi Isiah, The height that water can be lifted is limited by physics to about 30 feet or 10 metres, which is the maximum height of a column of water that a vacuum will draw, and is directly related to atmospheric pressure, which is what actually pushes the water up the column. Reality also intrudes in that, to lift water to this height requires that you have an absolutely airtight suction line, and, for anything other than a positive displacement pump, a lossless foot valve. Foot valves are anything but lossless, so the practical limit for a suction line to, say, a centrifugal pump, is probably around 6 or 7 metres. Big suction pipe diameters and low flow rates help, but this is still a fair ballpark limit figure. Regards Don B |
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| isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
Thank You for the info DonB. The one well or Bore is only about 25 feet deep so I should be able to get water out with one of those little pumps. The other well is 70 feet deep and I dont remember how far the water comes up the pipe, it dose have a semergable pump down in it. Weather here has turned on the cold nasty side so this project will wait ti it warms a bit. was 17 deg F this mourning!! Isaiah URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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| Don B Senior Member Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi again Isaiah (got the name right this time, I hope) The type of small DC pumps used in camper vans that I am familiar with are positive displacement types rather than centrifugal (or impellor) types and, as such, would not need a foot valve as their own internal valving makes this unnecessary. Another plus for positive displacement pumps is that they are self priming. The trade-off relative to a centrifugal pump is that they have more moving parts, and are less efficient, but for small quantities of water this is hardly an issue. If you have a pump on hand then you could certainly give it a try once you have thawed out. Regards Don B |
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| isaiah Guru Joined: 25/12/2009 Location: United StatesPosts: 303 |
Hi Don Don't worry about the spelling as I don't spell to well either and type even worse! I just hunt and peck usually I have a whole line typed and discover the caps were still on. The pump is still in the camper so Ill have to get it out and get things ready for a try. It didn't get above 34 f today and now we got a strong south west wind Makes it rough on old bones. I did get some house repairs done today so now I can get back to my other projects, I have a solar panel rack started for Bub73 that needs finished if we don't get snow. Isaiah URL=http://www.motherearthnews.com/Renewable-Energy/1973-11- 01/The-Plowboy-Interview.aspx>The Plowboy Interview[/URL> |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I've put this post plus a circuit and the PicAxe code into a page on the web site. See http://www.thebackshed.com/Windmill/articles/SolarPump.asp I'll put together a page for the hydralic ram at a later date. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| paceman Guru Joined: 07/10/2011 Location: AustraliaPosts: 1329 |
Great write-up Glenn - and thanks for including the schematic. Greg |
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darcyrandall200 Newbie  Joined: 17/01/2009 Location: AustraliaPosts: 34 |
Hey Glen, Can you please explain the purpose of the coke bottle downstream of the pump in more detail. Is it used to prime the pump? Thankyou. Regards Darcy Randall, Perth Western Australia |
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norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Glenn, Would love to see your circuit incorporate a maximiser, allowing the pump to run without a battery. I believe I`ve solved the continuous running by carefully wrapping 1/2 inch soft copper tube around the motor (5-6 wraps) and running the discharge water through this copper. Perhaps even a voltage regulator so as an oversize panel can be used allowing for pumping during cloudy conditions and not running overvoltage when the suns shinning brightly. Recently melted the brush holder(plastic) on the 12v double ended ebay pump (running at 24v+) I`ve been trialling. Unfortunately because it has a pump at each end of the motor, the brushes were getting no cooling. The single ended pumps I`ve got have metal brush holders. It was pushing out up to 20l/min drawing near 8 amps at 5m head. We come from the land downunder. Vic |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
darcyrandall200 not sure what coke bottle you mean. The one down stream would be the one next to the pump. Its a pressure vessel, or accumulator. By having a air cushion, it makes it easier for the pump to start and smooths out the flow a little. Without it, the pump would need to work much harder, especially in the first couple of seconds. The other coke bottle sits at the bottom of the pond. Its basically acting as a pre-filter, to stop fish and other critters getting into the system. Its made with a coke bottle, a few rocks in side to make it sink, and about 50 little holes, about 3mm diameter, made with my soldering iron. It works well, there is also a fine gauze filter just before the pump and its remaining fairly clean, maybe a teaspoon of slime in it after 2 weeks. norcold yeah I'll look at adding some more smarts to the circuit and code at a later date. At the moment its doing its job and I have more pressing matters, like finding ways to pay the mortgage 
The pump has a 1:2 duty cycle at the moment, 10 seconds on, 20 off. Its not even getting warm, so I might look at increasing that to 1:1, or even 2:1. So long as the motor keeps its cool and I'm gathering enough sun to power the thing. I also need to monitor the ponds water level, if its showing any signs of dropping I'll reduce the duty cycle. I think it should be OK, water seeps out of the rocks above the pond water level. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Our water situation is similar. My seep stops completely some real dry years. This is one. So I got a dozer in a few years ago and made a dam below the seep, this solved the water quantity issue( holds about 3megs when full now), so I can pump continuously. Unfortunately disturbing things stuffed up the water quality, as per other thread. Thus this years cleanout. Understand the mortgage neck rope, been there. Can help you out, trade our ages for our finances.  We come from the land downunder. Vic |
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