Using solar power & 12 Volt pump

[DaveOponic]

I have just been given two Shell Solar panels (ST20) and a Steca Sigma charging regulator. All I need is a battery and a 12 Volt pump and I should be able to run my new system on solar. We have some blackouts here that sometimes can knock at power for a day or more (longest was 4 days)

Has anyone used solar to power their AP system?

Any recommendation on pumps? I have bought a cheap Chinese made bilge pump (the only one I could find in Brunei) but it looks plasticky and may not be very reliable ... I have 1000 litres tank and plan to have eventually the same volume in growbed space. The growbeds are at about a metre height.

[Murray]

Hi Dave,
We have trialed systems on 12 volt for months in the past and found that the 12 volt pump was the letdown. It is difficult to find continuously rated DC pumps, unless you are prepared to spend a whack of money.
It is much easier to find a low watt age mains power pump and use an inverter.
You have to have a fair bit of solar panel to produce enough power to run a pump 24 hours a day. Just do the sums on watts needed times 24 hours, then multiply the watts capacity of your panels by about 6 hours. In Brisbane the average sunshine per day (for solar panel best efficiency) year around is 6.5 hours. Where you are may be similar or maybe even less bringing into account cloud cover etc.
So you need enough watts produced in that 6.5 hours to service the daily watts draw of the pump. Then you need more watts than that. During the night your battery has run down, so the watts of solar panel needed will need another factor of watts output to be able to bring the battery up again ASAP to full charge. About another 15% above your first calculation.
Don't forget to allow about another 3% of the total Watts for inverter and system inefficiencies.

When you have that all worked out, then you have to multiply the watts by the number of days you hope to hold the system up if there is constant overcast and rain and the solar panels will only be putting out 10 or 15 % of their capacity.

Don't forget to work out the amp hours of battery capacity needed and add the appropriate number of batteries to your system.

A reliable stand alone solar system for a domestic aquaponics system is not an inexpensive exercise.

[fishfood]

Has anybody done the sums on the total cost of a solar setup and compare it with a system on mains power and then a breakdown on how many years for the lines to cross also worth note here in vic there was a few areas that did not have power every body [ had the best system out] but as soon as the power was close 99.9 % connected to the mains

[Murray]

FF, we are very close to putting a couple of systems up on our website. We have been playing around with it for some months.
It is not as easy as it may first appear, and is expensive to make it really work.

[Murray]

FF, we are very close to putting a couple of systems up on our website. We have been playing around with it for some months.
It is not as easy as it may first appear, and is expensive to make it really work.
Solar driven Aquaponics is the "holy grail" to a lot of people who want to move toward sustainability, but be prepared to spend some money.
Good equipment is a prerequisite to success in any field of endeavour. It is ok to recycle but the same rule applies, recycle with good equipment properly built and connected etc.

[fishfood]

I am not nocking solar or sustainable but there has to be a line where there paths cross I for one would not be wanting to eat $20 fish for 10 years one bloke i know had a stand alone setup and in the end he spent $50000 to connect to mains 1 km underground trench [enviromently sensetive area]

[Dufflight]

I like the idea of a solar setup for air. The water pumping would be good also but the o2 in the water in case of power outages is something I'd like to setup. Plus it would be a cheaper system that could give people a taste before they go all out on a complete system.

[DaveOponic]

Thanks for the feedback Murray & others...

The two ST 20 Solar panels and charger regulator were given to me partly in exchange for building an AP system (barrelponics type system) for an expat Kiwi here.

The two panels give 40 watts. I haven't done the maths but it seems reasonable that they would keep a lead acid car battery charged for running a pump and air as a backup. My system runs on a timer at present 15 minutes on and 45 mins off (240 volts) An inverter sounds like a good idea. I haven't priced them here yet though.

We have no shortage of sunlight here on the equator. An overcast day is a blessing but it rarely happens! Torrential rain storms interrupt the sun's rays for 20 - 30 minutes before it starts beating down again. So I can't see lack of sunlight as a problem here.

I have attached the manuals for anyone who is interested.

Dave

[Basalt]

I'm planning on running my system (currently in the early stages of being built) from solar. I got hold of one 80W panel and one 40W panel and a 30 amp controller from my parents (no longer needed) and have salvaged nine 12v 5AHr gel batteries from a UPS at work.
I've bought a 380w (650w surge) pure sine-wave inverter from Jaycar for $209 to run the water pump and a small air pump.

I'll le you know how I get on. (with pics).

[Hamish]

Hi Dave - perhaps try pumping with an airlift pump to move the water around. It would be slow pumping but reliable. Being operated by a very low wattage air pump it might be just the ticket to run off solar.