Backyard Aquaponics
A place to discuss aquaponics

thats about the same as we pay here DT. Assuming your country is quite a bit poorer than ours (no offense meant) we are getting it way too cheap or you are paying way too much. Personally I think we could pay a little more if they stopped concentrating on coal and used the extra money for investment in renewables. As if that is going to happen GRRRR

We pay about the same per Kwh, but we have the choice of where our energy comes from. The cheapest power is coal or natural gas, but for only a little more we can specify that some or even all of our power is generated from biomass, wind, solar or hydro. I like that we can support renewables even if we can't put a solar array on the roof.

You've confused power and energy (don't worry, 99% of the population gets that one wrong). 380Whours. You want this to work mid winter, so let's say 4 hours of 50% sun with a max time between suns of 3 days - you'll need to store 3 days worth (720Whours / 12V = 95Ah battery, maybe $280 for a deep cycle?) and collect say 1.5 days worth each day (360Wh *1.5/ 2 hours = 285W solar panel = ~$2850). You can derate as your budget allows.

NJH, maybe i am part of the 1% pop, but the calculation for available sunlight seems pretty harsh for our environment (aust) even for winter. I think I have noticed that solar panels still generate power on an overcast day (is this correct) or is this the 50% generation that you are assuming?

Even in winter there are 8 hours of light, even if it is overcast.

FJ, I think njh was probably refering to the fact that unless you have a solar panel sun tracker, your panels only produce power for a few hours of the day when the sun is directly on the panels. Solar panels is probably a whole new topic by itself, I've been looking at the differences between normal crystaline cells and amorphous, so many different things to think of...

C1, I spose a smaller unit could be possible, but for initial costs, it's cheaper to build one larger system than it is to build numerous small ones.. Perhaps...

SS, I've been wondering about a system with a header tank, and I've been working on a design that has one, I might post it up in a seperate thread...

I like the slow pump to a header tank idea.

EB and Steve S, check out my recent topic of "Auto flooding mechanism".
The design has a stepped multi output....without power. Check out the "Flout Types" page at the link I posted.

I'm just looking at it now Hayden, that's a very simple device... Won't fit well into a growbed, but into a header tank of some sort, I like the idea..

I think I will try to make one tomorrow for by barrel header tank...seems very easy to construct....its one of those things that makes you really excited and want to stay up late making one.
I get my continuous flow, and lose the complexity(despite its simplicity) of the barrel-ponics flood valve. High flood rate is very attractive to me.

The basic rule when estimating solar output from an PV array is to find out the average hours of sunshine per day over a year and then roughly estimate that your array will produce something like its rated output for that amount of time. I live near Canberra and work on an average of 5 and a half hours of sunshine a day- over the whole year.
So my 3kw array should produce about 16.5 kwH per day. In fact we really get something closer to 12kwH per day overall.
One of the problems with photovolaic cells is that their power output drops when they get hot so the actual output per hour is actually lower in mid summer than it is on a sunny winter day with a few clouds in the sky. Obviously more hours of sunshine in summer means we still produce more power overall in summer.
To reiterate - my calculations suggest that I will need the output of 160watts of panels to run one 700watt pump for 5 minutes an hour for the 24 hours in a day.