Backyard Aquaponics
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With that amount of battery I can run for (I think) days.....

Id need some more details to work it out but I doubt that, remember you can only run the 12v battery down to 50% max.
Add an inverter to the mix with significant inefficiency and youll get closer to the real answer.
I might be missing something and you are correct but often people overestimate this back up capacity

Id reckon with 45W AC pump you might get ~24hrs

I just found these too way oversized but they dont do smaller ones.
http://www.invertershop.com.au/600-watt ... 2v-dc.html
Brains out af a UPS and does the recharging too - not too bad value if you consider it replaces battery charger too.

For anyone looking at Backup systems

If you do not have some type of power stabilising device in you backup system, you backup system may actual damage any device’s that are hooked to it, for example here in port Pirie we have the largest lead smelter in the southern hemisphere, with the type of power they use down there we get large fluctuations in power here eg power can drop below 200v eg brown out! Also power flicking on and off, these are killers of electrical devices! ( aswell as run very high 250v or more! most things are rated to 220 to 240 the insulation will break down at higher values)

A system that uses power that flicks on and off at a fast rate is called a tesla coil (look it up if you haven’t seen one run!) now imagine this happening in the windings of your Pump or any other device that is hooked to it, normally this will not happen and when it does it shouldn’t kill you pump but it will reduce the life of the electrical device!

Now A UPS has battery’s and Capacitors that smooth out the voltage much like the Sump tank in a AO System stops the water fluctuating, and it stops the surge of electricity that would normal cause you a problem, however sometimes the UPS fails instead hahaha.

Make sure a system will not flick backwards and forwards as Mains power comes and goes without some safety measure in place to stop surge voltage causing a problem, battery, Capacitor, Timer that kicks you back to mains after a certain time or something!

The reason I’m point this out is amph is a Pirie lad and will I’m sure knows what I’m talking about!

I got mine from the camping section of K-mart <hang head in shame>

Thats where real men shop for camping equipment

Hey guys i just spent $52 U.S. for back up system. that included two small 12volt batteries, inverter, and two relay contacts one always open one always closed. I have it hooked up just to my air pumps. It runs on main power system until their is a power cut. Then because the two relay contacts are in place it automatically goes on until all the battery is drained. Works great. I estimate that it will last for about 8 hrs on the two small batteries since the two air pumps only put out 4.5 watts each. I figure that the growbeds/plants can survive for a long time without water being pumped into them but the fish won't survive for a long power outage without O2. You obviously have to keep the batteries charged with however you want to do that. These things were easy to find here in Botswana so I assume you should be able to find them in Austrailia.


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