Backyard Aquaponics
A place to discuss aquaponics

IAP and I have set up a backup system.
We have a 40Ah battery on a trickle charger and will attach a 12v air pump as soon as it arrives. (Should have been here weeks ago, finally got the skip from the post office but it's STILL not here).

We have attached a 12v light to the system which can be seen from inside the house so we can tell if we are running on mains or back up.

Only problem we still have now I'd that I've tried to wire up a float switch to my submerged pump but an not succeeding. The pump works when the float is up but as soon as you drop the float it trips the circuit breaker.
The switch is wired in series (I think I managed to do that)

Please, any advice

Hi Thabo
Not sure about Israel but in Australian wiring you have the Active and neutral around the wrong way
(Active on the left from the back of plug with earth down)
this is not normally a problem as AC is bi-directional but it can cause earth leakage breakers to
drop out.

I think you have also wired the switch wrong - I don't think it should have an earth connection
check it with a meter or check for a diagram but I think you will find that one wire is normally closed and one wire normally open and one wire common (most likely the red common but who knows!) so your switch is just connecting the red to earth when down and tripping the breaker. taking the yellow out of the earth and insulating it leaving it disconnected should work

Hope you get it sorted

Thanks Johnh

How's your Chinese?




I'll try test it with a multi meter later today

Cant make a lot out of that

But from the pictures you can use it for filling
that is Turn off when high

or emptying
Turn off when low

so I would think my first guess was right

Use the red and blue like you have and leave the yellow disconnected and insulated
if you want the pump to run with the float up

Use the Red and Yellow and leave the blue disconnected and insulated
if you want the pump to run with float down

i must admit that if you need a plane fixed (especially non standard repairs on large passenger jets) I'm your man... when it comes to electricity, the sum total of my knowledge can be summerized as follows -
stick your fingers in a socket and all the hairs on your head, even those in your ears and nose, will stand on end

using a multi-meter i found that as i switch the float from on to off (up to down) i get a quick signal running through the earth
i assume that means that the switch is very sensitive and i need something which will prevent this happening.

in the meantime i have disconnected the earth and it works nicely now, but to my small mind if the manufacturer made it with an earth there must be some reason for it.

You are reading it wrong
the manufacturer did not make it with an earth (the cable is not green or striped green is it? )

As my post above one wire will be switched to the common with float up

the other wire will be switched to the common with float down

so one wire is the common supply
one wire is made to drive the pump filling
one wire is made to drive the pump emptying

no wire for earth

you know what?
you are right.
the 3rd line is yellow only and not an earth.

thanks

can't quite make what the float switch is for please

Iap has his pump in the sump tank and the height of the water in there fluctuates quite a bit. I want to make sure we don't run dry by mistake.

... we have had enough balls ups that I don't want to take any more chances

same thing I've been concerned about then. Cool thanks. Oh, and the bulb looking thing? or is that the switch?

That's a 12v bulb which goes on if the mains trips and we start running on backup.
We have another low energy bulb connected to the mains.

They are in separate locations so that we do not confuse them.

Both of them are viable from the house or entrance-way.

Next step is to change colors so that it's even easier to differentiate between bulbs

yes very cool.

Hi Brian
the Yellow and blue plastic thingo on the end of the wire is the switch
simple to instal these. Just cable tie the cable to a convenient pipe
or something so it either floats up to the level you want to turn on (or off)
or hangs down to the level you want it to switch

In this case Lap does not want his pump to run dry so it is wired so that when it is hanging nearly
vertical it cuts the pump out, as soon as the water rises a little it will switch back on.
With the right use of contactors or relays instead of direct wired you can make it switch
on at the top and off at the bottom or vice versa

Hope you are feeling a little better! any more stones and you could start a media bed

Excellent thread, thanks Chainsaw and others for all the info.

I've just started building my AP system and I'm looking into power backup options as we've had about 4-5 outages so far this year, the longest being about 4 hours. I've purchased a Laguna Max Flo 2000 (75W) and I already own a CTEK MXS 7.0 which provides max 7A charge and has a float mode.

I'm planning ahead for a large-ish backyard system with 4000L of FTs and maybe 6x 300L grow beds. So my backup system will need to push a lot of air to multiple fish tanks but I'd prefer to use an inverter to keep my 240v pump running.

I'm wondering how long a 100Ah deep cycle battery will power this pump using a 300W sine wave inverter from Jaycar, eg, the one below. An expensive pure sine wave inverter doesn't seem necessary - correct?

http://www.jaycar.com.au/Power-Products-Electrical/Power-Conversion-%26-Transformation/DC-AC-Inverters/300W-%281000W-Surge%29-12VDC-to-230VAC-Electrically-Isolated-Inverter/p/MI5104

Using the tool below with 0.312A for AC amps (75/240), it says I'll need 6.9 DC amps.

http://www.batterystuff.com/kb/tools/ac-to-dc-amperage-conversion-run-through-an-inverter.html

Add 10% for inverter losses, call it 8A. By my calculations a 100Ah deep cycle battery will provide roughly 12 hours backup for my Laguna pump. Does that sound right?

It's unlikely that you would get 12 hours for several reasons. The 90% inverter efficiency is likely the maximum, and it will be lower at higher and lower power levels. You'd need to see its efficiency curve to find out what it might be for your load.
The battery will be rated for 100AH at a certain discharge rate, probably C/20 or 5A, if you discharge at higher than that, it will have less capacity, due to Peukert's Law.
Modified sine wave inverters can make motors run roughly, some things wont run at all, it depends on how close to a sine wave the output is.