Backyard Aquaponics
A place to discuss aquaponics

On efficiencies am I missing any?

Transmission from PV panels to Pump 95% (5% voltage drop)
Pump Efficiency 70% (I can get better than that)
Pipe Efficiency to Header Tank 99% (Using a 250mm pipe)
Pipe Efficiency to Hydro Generator 99% (Using a 250mm pipe)
Hydro Generator 80% (according to G)
Transmission to System 95% (5% voltage drop)

Overall efficiency 57%

From a ML of water that would be 136kWhrs.

How much would 136kWhrs of Batteries cost?

Look into lining dams with synthetic liner, clay wont suit high fill/drain cycle and water will get dirty
If the clay has to be carted in, a good Rubber liner will be similar cost.
$5K dam price is maybe kidding himself

On something like 1-2 Ml dam covering isnt out of the question either, keeping water clean will be important
Anchoring solar or pumps etc on dams this size isnt too hard. Id have thought difficulty of maintenance and water ingress would plague floating panel systems.

err yea, l/s

I'm planning to use linear actuators to close the ball valves here, plus I have a blow-off valve, just to be safe in the event of a too fast manual valve close!

Your pv panels will be producing say 500v DC (unless you use micro inverters) Gordon can correct me on this but you need an MPPT controller and a DC to DC converter and an inverter if you are using AC pumps. What is your turbine producing AC or DC?

Dirty I'm not worried about but what would be the problem with the fill drain cycle? Erosion or something else?

Erosion can be dealt with pretty easily.


The $5k price is for where the clay is. Other sites on the property would cost more. Although having said that If I was to get it done I'd probably build a dam some where else (bunded dam on the ridge) and use the hole left from excavating the clay as the lower dam.

The operator who gave the quote is good at his job and has all the big toys but I'd would get the owner to deal with him because he doesn't like me.


True but it would substantially add to the cost.

Where the water is relatively still its pretty simple. Even if the water goes up and down regularly its not such a big deal. Going up and down every day though might be more of a problem. Also having a much larger dam say 10ML would mean that the change in height from removing 1-2ML wouldn't be so great.

Oh and I forgot to add your dam will attract birds and it is likely they will crap all over your panels.

Yeah erosion, but just moving water in small dam stirs up any good clay.
Yes liners and covers cost heaps but depends what water is worth - in this case what power is worth without it.
if your talking 10 mg plus then yes covers probably out.
If the water is going to be used in greenhouse too, filtration and disinfection become big costs.

Ive had some exposure to floating all types of things and if theres a choice avoid it. Rooting around in boats trying to diagnose problems then fix them or even cleaning duck poop off panels is for the keen only.
With current pricing I'd look at tracking frame mount setups, pumps on bank or subbies
Maybe its a case of practicality over riding pure efficiency, maybe I just dont like getting wet.

I can't remember the specks but the French system is rated for use in rivers in flood.

The birds are an issue that I hadn't thought of

There are a few ways to do it, but if you can have all the PV, pumping and AP reasonably close together, electrical line losses should be well under 5%.
Turbine alternators will be producing 3phase AC until recitfied. It really comes down to what voltage battery you want to run as to which is the best way to go about it, but it's best to avoid too many DC to AC to DC conversions. I'd be more inclined to go with a 52V (16 cell) Lithium battery and use MPPT charge controllers, and either DC pumps or pump controllers that convert DC to 3phase AC like I have here.

136kWh batteries could probably be done for <$100K including everything you need if you went with buying your own cells, but I don't know what cost a commercial boxed battery system of that size might cost, other than somewhat more than that.

If you were going just with batteries, you could do it in a modular fashion, start small- just put in a PV array + battery etc for each 1kW system, add a module (5kW PV, 1 MPPT charge controller and a 15kWh battery) each time you want to expand.

Ok so pumped Hydro is looking good for later.




I think if I went to that site or another one that had similar options I'd go with PV, Batteries and Genset backup to start with.

As power requirements increased their would be a point at which the pumped hydro would be worth doing.

There is another block I looked at a while ago that the agent just contacted me about again. Its had a significant price reduction but the reason it is pertinent is because it is at the bottom of a hill.

Its not particularly steep so it takes about 900m to get 70m of head. The avantage though of having the system at the bottom of the hill is that I would only need to have a pipe running up the hill with no need for cables.

I'd have to convince the neighbour though that owns the hill.