Posted: 2/4/2008 3:43:23 PM EDT
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Hey, trying to set up a solar panel system for the farm pond pump. Gas is too expensive to run from generator and am looking to convert to solar set up. I have a 120 V pump that is rated at 5.5A. 115A/hr deep cycle battery. I am wanting to run the pump about 1-2 hrs in the day time to aerate the pond for the fish. I know I need an inverter (what size?), and a panel set up. I took Electronics Technology in the early 90's, but have looked for the worksheets concerning this and not quite able to figure everything up. Looks like I need a 50-75 W panel set up? I don't know, and with the price of the panels, definitely gets expensive quick. Can anyone help? Thanks |
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If I did my numbers correct - you will need about a 750 watt inverter 120*5.5=660 watts If you run the pump for 2 hours or 1220 watts divided by 4 hours of full sun per day = 305 watts or about 4 x 75 watt panels. Your battery is too small as it will not provide a full day of back up power for no sun. 115 ah x 12 / 2=690 watts before reaching 50% discharge or just over an hour of pump use. Also, fast discharge is more harmful to deep cycle batteries than slow discharge. A 300 AH would be better. If I've made a mistake I apologize as I am a layman who is also pursuing alt energy and it helps to run these numbers out loud for the experts to critique. |
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Actually, those numbers are almost identical to what I came up with initially. I thought they must be wrong since it would require so much to run one pump and people run entire houses off of these things. That many panels would be extremely expensive, along with the controllers to keep everything safe. Can someone verify these numbers? Seems cost prohibitive. |
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I don't know much about fish, but if you are just blowing bubbles in the pond (aeration), could you use a cheap small 12 volt air compressor? Those thing wouldn't use many amps and could be run without the inefficiencies of inverting. The pump draw seems excessive for the goal. Most houses would run between 12000 to 24000 watts per day without heat and hot water and require 20 to 40 150 watt panels without serious energy effecient appliances. |
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A pump that draws 5.5 amps at 120 volts (660 watts) is pretty good sized. Are you sure you really need that big a pump to keep the fish alive? The average 12 volt RV/Marine pump (Sure-Flo, ITT/Jabsco, Flojet or similar) only draws around 50-80 watts, and yet still flows a lot of water. There HAS to be a more efficient way of accomplishing what you want to do. |
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That's almost a one horse power pump. It is sized for pumping water, lots of water. If you can do the job by pumping air into the tank you probably do as good a job of aeration and need less energy/power. Be careful, though, as you would not likely get the water circulation you would by pumping the water. Does this pump also act as a filter system pump? Don't forget to look at the motor label. It will likely tell you the starting current you need to get the motor going. This could be as much as twice the current used once running. |
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There are well pump systems designed specifically for solar. The cost of the system depends on how deep your well is and how much water you need each day. Solar Well Pump Pricing |
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Yea I think this pump is probably going to be to big to do what I want to do. It is a pretty big pond, specifically for catfish and bream. It is about 400 ft long and 150 ft wide, man made pond. We used to have a hard time keeping the fish alive due to the oxygen levels in the pond getting low when there was no rain. I live in S Ga and if anyone has been paying attention, last year was one of the driest on record. The pump kept the fish alive though, but cost a fortune in fuel for the generator. I don't know that a small RV type pump would aerate enough to do the job. I do like the ideas that are coming out though. I am sure we are going to hit on something soon. |
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To just put air into the water all I ever seen used was something like THIS. I would not use a water pump unless it was for some sort of water feature display. That is the only real reason to use a water pump, unless you are worried about freezing, but that is not your case. Water is 800 times more dense than air, and naturally uses more power to move it. I would not use air from just any source like an air compressor. They will pump air and OIL into your pond. One quart of oil will ruin 1,000,000 gallons of drinking water. You have a pond that is 1.37 acres. I myself would have 2 or 3 small aerating pumps. Then you could maybe start to look at a small solar system for each one if you wanted. Plus if one went down, you are not "DEAD IN THE WATER" so to speak.  I think since these do nothing but put air into the water, your run times would be less than a water pump as its main objective is to just move water. |
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I was reading a magazine and found an add for Koenders aeration systems. Apparently, there are a bunch of folks that make windmills just to aerate ponds. I googled 'pond aeration windmill' and found a whole bunch of others. If you get any wind at all, this might be a more simple solution. R. |