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Solar powered pumps
http://byap.backyardmagazines.com/forum/viewtopic.php?f=8&t=9148		 Page 1 of 1
Author:  PaulR [ Feb 24th, '11, 15:10 ]
Post subject:  Solar powered pumps
Hi

Am new to AP and am thinking of going solar. 240V mains supply here is not the most reliable. Can easily get hold of a 900l/hr pump that suits my FT size. Does anyone have any recommendations about going solar? What sort of timer can be used with these pumps given they are not connected to the mains? Is it OK to NOT have the pump running at night time? How reliable are they generally? :?
Author:  earthbound [ Feb 24th, '11, 16:02 ]
Post subject:  Re: Solar powered pumps
Hope you have a really small system IHS because a 900L/h is only very small. Is the pump AC or DC?
Author:  steve [ Feb 24th, '11, 17:17 ]
Post subject:  Re: Solar powered pumps
also realise that flow rates are usualy given for no "head" or rise in the pipes. you might find that it reduces quite alto as you go up.
Author:  PaulR [ Feb 24th, '11, 17:55 ]
Post subject:  Re: Solar powered pumps
I only have a 1000litre tank. Yes, by comparison it is a small system but it should be enough for us at home. I have no plans to go commercial.
Author:  steve [ Feb 24th, '11, 18:19 ]
Post subject:  Re: Solar powered pumps
A 1000L system is not all THAT small! :)

i guess you just need to do some calculations to see if the pump would suit or not.

what are the volumes of your growbeds?
how high are they off the ground?
does the pump say what its maximum head height is?

when you consider a 1000L system usually having at least one growbed which contains approx 250L (is this right guys?) of water when flooded and that it would be "flood cycled" every hour in most systems then thats gives you a flood time of about 17mins (at best) with your pump and that without pumping to 1m height.

Can you post us some more info on the pump you're talking about?

I think we are assuming is has built in solar panels hence the assumption on its poor performance. i've just done a search on some DC well pumps that are positive displacement and have fantastic flow Vs pumping height. if its one of these then you will probably just scrape in.
Author:  earthbound [ Feb 24th, '11, 18:28 ]
Post subject:  Re: Solar powered pumps
Generally we aim for a 1500-3000L/h pump in a system that has a 1000L tank.
Author:  arbe [ Feb 24th, '11, 19:51 ]
Post subject:  Re: Solar powered pumps
What about a UPS as a backup in the event of mains failure using a normal ac pump or solar panels, battery, inverter and a normal ac pump?
Author:  PaulR [ Mar 2nd, '11, 13:52 ]
Post subject:  Re: Solar powered pumps
Hi All

Sorry for taking so long to get back to you. Many thanks for the feedback. Was going to aim for about the two to one growbed to FT ratio in the longer term. That would give me 2000 litres of growbeds or 20 half barrels (which I can get over a period of time). Probably end up with about one to one to start with and low fish stocks. I estimate a height of less than 2 metres. Will probably have to rethink the pump option to something bigger. Does anyone have any suggestions for make or models?

Conergy make some solar powered DC pumps that look interesting but have not had a reply from them yet.

I have been running the pumpt on my small system now during day light hours only and it has not seemed to affect the plants or fish so far. But its probably too early to tell. Would like to get away from battery backups if I can.

Cheers
Author:  PaulR [ Mar 2nd, '11, 13:58 ]
Post subject:  Re: Solar powered pumps
Thanks Arbe

What brand of UPS would be thinking of? I have one on the home computer because of the power supply problems we get here but it is only good for about 30 minutes, which gives us plenty of time to finish what we are doing and shut down. It's nothing for us to be offline for several hours at a time. Not to mention the fluctuations and spikes in the supply. Plays havoc with your data at times; thats why we have the UPS.
Author:  arbe [ Mar 2nd, '11, 14:08 ]
Post subject:  Re: Solar powered pumps
I usually would suggest an inline UPS. This is a UPS which the battery is constantly providing power to the devices while the mains keeps the battery charged. These are good where your mains power is not clean.

Having said that they are more expensive.

Can't really suggest a brand as the gear I work with and know is cost prohibitive to most (ie it is 3 phase and 60kVa plus)

edit:
Perhaps you only need a relatively small UPS to provide air for your fish. Your plants should survive a while with out water. This is one of my plans - with a backup plan if the plants start to struggle to bucket some water from the tank to the grow beds.
Author:  Shortie [ Mar 2nd, '11, 14:37 ]
Post subject:  Re: Solar powered pumps
soalar power is all good when the sun is shining.
I would be using solar to charge a bank of bateries. Then running the pump of the battery banks.
Ensure that the solar panels have enough juice o keep the batteries topped up. And ensure your pump will run adequatley overnight on battery power beofre the panel top up the batteries the next day.,
Author:  PaulR [ Mar 2nd, '11, 19:58 ]
Post subject:  Re: Solar powered pumps
Thankyou all again

Have found a 12/24V pump that will push 1900l/hr up 2 metres and looks like it will run off a solar panel.

Should be able to run a simple flood and drain system relying on a float switch just to keep the water level in the fish tank up to a decent height. I have read that some AP systems only run their pumps during the day light hours. What are the pros and cons of this?
Author:  arbe [ Mar 2nd, '11, 20:24 ]
Post subject:  Re: Solar powered pumps
I have heard of some systems only running during the night in the hotter months to keep the water temp. down as the grow beds tend to act like heat sinks.

One thing to watch out with when only running your pump for part of the day is the amount of dissolved oxygen as the splashing water adds DO to your system. If you are only going to pump for part of the day you will need an air pump as well (well maybe all systems need an air pump, but systems which only pump water for part of the day will need a bigger air pump)
Author:  earthbound [ Mar 2nd, '11, 20:27 ]
Post subject:  Re: Solar powered pumps
Yep, bit of a juggling act, gotta keep your fish happy..
Author:  PaulR [ Mar 3rd, '11, 16:57 ]
Post subject:  Re: Solar powered pumps
Looks like a battery backup is required for nocturnal use then! :think:
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