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.

[Jason Palenske]

I wish we were all on the same continent sometimes. Being able to find half of this stuff would be just amazing.

[Tony]

Hi Murray.
Have you had any luck yet at posting a suitable selection of solar gear on the web site?
I am currently looking at setting my entire system up as solar including pumps and air.
I am quite surprised that with batteries, 240volt inverter (best way to go), and panels, that it does not look like it will cost as much as anticipated. Probably I will get away with about $1000. A firm costing will be available in a couple of weeks, so I'll post exactly what I order complete with power calculations of the entire system and so forth once I get the details.
That is for running 2 x 100w pumps and air pump 24/7 allowing for an average of 6 hours per day of sunlight. I will also put in a relay that in the case the batteries run out, it switches to mains power. Just in case.
Cheers
T

[Outbackozzie]

Hey Basalt - 45AH can only power a (240v) 65 watt (4500lph) (draws 5A @ 12v) pump for 4 1/2 hours to 50% discharge (as far as you should discharge any battery, deep cycle or not).

I'd definately add a couple of big car batteries to your bank. 100AH (50AH useable) landcruiser batteries can be had for just over $150.

[echidna]

With batteries it pays to shop around. I just got a N120 for the truck, $150 delivered and installed - local Battery World quoted $200 plus a callout fee, The Super Charge importer quoted $220 delivered. I got 4 1/2 years out of the old battery (the tailgate loader is hard on battery life) so I'd expect 6-8 years easily if used for power back-up and not heavily drained frequently. The value of the truck batteries is hard to beat.

[Outbackozzie]

N120's are around 125 - 150AH also :)

They would last a lot longer than the landcruiser battery due to bigger plate sizes too.

Thats a really good price too.

[Murray]

Tony, I will be very interested to see what you come up with on the solar front. My experience with the solar world in general has not been very satisfactory I am sorry to report. When you find someone that is interested in talking about something else other than Gov sub house installs, their prices are ridiculous.
The lowest I can find is a China import company that can offer a drop shipment of 130 watt x 24 volt panels for 800.00 each Approx, depending on the exchange rate when they land.
I reckon the whole solar thing is a bit of a rip off personally, it is not as good as it is cracked up to be.
I am keen to have wind power as well to reduce the dependence on solar, besides, the wind blows at night ...often....depends where you live.

Really good marine wind powered gen sets can deliver 6 or 8 amps in a good breeze and cost around 2,500.00
I am thinking of making one myself out of a 24 volt truck alternator and make up a couple of big blades....be a bit of fun .
I have seen some instructions on the internet in the past, must dig them up again and have another look.

24 volts is better than 12 in the long run.

[Dufflight]

Last time I went sailing you could hear the wind gen's on the other boats. Great option if your near the coast and can get a lot of wind.

[DaveOponic]

I have built a weatherproof housing for my solar power unit. I also bought a 200 W 240 Volt inverter ($100) and the whole unit is ready to go as soon as I can lift the battery again ........ I had a hernia operation last week and so can't do much lifting/work for a few weeks.

I had some help today to get gravel washed and two new 250 litre growbeds ready to go with Bell siphons installed to empty the GB's in 2 minutes.

I still have one spare solar panel so if all goes well I will make another unit.

The torrential rain continues and makes me wonder about a water wheel as a source of pumping power. There is no shortage of water falling out of the sky here nearly every day.

[Finn]

All solar panels are not created equal. Right now the panels available on the market run between 12% and 18% efficiency. A couple of companies are planning on releasing panels in the 20% to 24% range next year and the are currently researching terrestrial based panels that will get 40% efficiency (expected release 3-5 years).

I have considered LED grow lights to supplement our shorter winter days. A good 45W LED can replace a 250W HID light at about 45% greater initial cost.

Lunch is over, more later.

Finn

[Tony]

I am looking into a domestic wind generator for my house in a year or two that will compliment the solar panels as we do get a stack of wind.
I didn't even give wind a thought though for a small system like the aquaponics, but the ones for sail boats is excellent and ideal... I will make some enquiries.
But Murray, there is another industry for you and your web site..! Home made wind generators.. Just in case you need something else to take up your time.
I got a price from the local solar company here in Hobart for a panel system and they have priced panel, inverter, battery, and regulator for $380....
I am recalculating their power figures though as I don't think the system is big enough.. Certainly cheap enough.! :p

[Tony]

Hi Finn.

You are absolutely correct on solar panels not being equal. I have managed to find one that is claiming around 20% conversion (Kaneka advertised at http://solarshop.com.au) and around $1000 for a suitable aquaponics based output.

I have also found a couple of sites if people are interested in building their own panels. I was surprised at how easy it is and could save considerable expense.

As Echidna has mentioned though, it really does pay to shop around for batteries. If there are any plans to expand the system later, then good batteries like a sealed deep cycle gel system that is maintenance free and can cope with high volume discharges is the way to go. Sounds like OB has a fair bit of knowledge on batteries and output requirements too.

And FF I am beginning to agree with you and Murray on the total costs output vs recovery of solar for a small installation for an AP setup. My basic (very basic) calculations are currently about 10 years before return (with no maintenance costs). I'll get back to you on that soon. I guess ideally though, solar and batteries with grid power back up allows for a bomb proof system. It would only have to protect your system once from failing to pay for itself.


Australian site - free instructions.
http://www.sungroper.asn.au/project/solar-panel.html

$12.95 USD PDF 147 page book. Sample pages look really well laid out and easy to follow. 3.7meg download.
http://www.goodideacreative.com/solarpanel.html

[Outbackozzie]

I had to learn how to calculate (simple maths) how big my batteries needed to be for my backup system.

You are correct on the 10 year payback for a small AP system solar array - however once the AP system gets bigger, it could become economical in a high sunshine area.

I will be looking into it once my system has all the extra pumps going.

[Reedien]

Solar power is energy harnessed from the sun’s rays.This retained the daily heat absorbed from the winter sun and reduced the need for burning wood. Solar panels perform in a similar way, with better results. Solar Power Systems Queensland (http://www.solarpowerqueensland.net.au/)

[RS_]

Having worked with many kinds of battery's, The Golf Cart Battery's = 220Ah Deep Cycle are the Best battery's that have the Capacity to run a larger system for extended periods. And you can get many many more charge / discharge cycles from them, compared to Car/Truck Battery's, or deep cycle Marine Battery's that are just basically beefed up Truck Battery's.

The Golf Cart Battery's are Pricey, but well worth the $$$, if you are planning a Serious size Backup System

12V systems are OK, but 24V systems are much better. As a 24V inverter will pull 1/2 the current as a 12V inverter running the same AC Amp Load, and last 2 times as long

[GaryD]

Hi RS,

People often overlook the fact that car and truck batteries are designed to discharge at a very high rate for short time.....when starting vehicles. Current battery technology has turned the automotive world on its ear because they don't behave quite the same way that traditional lead acid batteries did......particularly when it comes to charging.

I'll have to check out the price of golf cart batteries in my area......a good idea that I hadn't considered.

Gary