Backyard Aquaponics
A place to discuss aquaponics

G'day all, I found this kit on jaycar and it looks like it might be good for running back up 12vdc power
http://www.jaycar.com.au/productView.as ... eyword2=KC
What do you guys think?
If you smart people think it might be ok I will get one and try it out!

Yeah, plug a bigger battery into it, and you could power a decent aerator for quite a while, or bilge pump. Depends on the max power output.

It would be a very good way to power up an inverter for 240 volt gear too.

yeah thats what IO thought, I have a 50 AH battery here to use, I think it said max draw was 5 amps.

12v @ 5A will power an inverter load of 240v 50watt with a bit to spare.

How long would the 50 AH's last through an inverter compaired to just running a DC bilge pump or airpump?
I have a 5amp 800GPH DC bilge pump that could plug straight in.

50AH at maximum load of 5A = 10 hours. Realistically around 7 before low voltage cut off. Your only really want to draw from it for 5 hours before you start damaging the battery.

But the bilge pump (seeing as you already have one) is a good option

I am going to make a failover switch using this 240 volt Relay



http://www.jaycar.com.au/productView.as ... BCATID=754

and a junction box, GPO and three prong plugs I have lying around, for ~ $20 I will get the same sytem you can pay $125 for. Used together with a 600W inverter and my three stage charger and a large deepcycle battery I think I will have a cheap and versitile emergency back up system to run my air pump and maybe even a small sump pump aswell.

I know all of this has been mentioned earier in the topic but I think this system has distinct advantages over a UPS designed for a computer:

- Variable battery size to suit different systems
- Inverter can be used for different functions such as running an air pump in your car to get your fish home alive
- Separate charger is always useful to have
- I can use the battery for other functions such as running the kids electric ride on car.

And one big disadvantage (in my eyes) - you do not know if it has failed until the power goes out.

That is the main reason why I run my backup 24/7 - so I see straight away if it is not working.

Ok so slowly getting my stuff together and backup power is a must.

Planning on using my projecta battery charger (1600mA) and an Inverter I relieved my brother from .
The Inverter is Modified Sine wave but only 150w output, should this be enough? I know it's a tricky question without knowing as yet the wattage of a pump and air pump but any ideas are welcome

Im working through this at the moment
Re 100W inverter, watch the starting current of pumps, 100W pump may draw 300W to start

Im on the same track as Simo
I have a 240V 4 pole relay which will transfer power supply from mains to inverter if mains drops out
Spare pole can start 12 v relay whch starts inverter

BUT will it be OK to transfer load to inverter and provide it with 12 v at the same time?

Running inverter the whole time is OK but they use fair bit of standby current and they do wear out.

remember once you have a battery you have a constant 12v supply, while allows you to use 12v relays to turn such things as inverters etc on...

id be using a 30A Car Style Relay as the switch on the inverter.

also if your switching your Supply's between Inverter/mains to the same Pumps etc, i think you need timers to allow it to have some grace time between switching, this would also give your inverter time to warms up and get ready also Brown outs and those times where mains seems to flicker could cause your inverter to get blown up etc.

Iv Built my Control Circuit with Heavy Duty Commercial grade switch gear, and a brand new 30A Relay to switch the Inverter on and off.

there has also been ideas thrown at me from electricians to use a UPS off a computer system and then exchange the 7AH Battery's inside for a Car battery or two this takes care of all the switching and fall over.

I have plenty of ups's lying around schools with dead batterys that are never going to be used again. Is just a matter of connecting the car batteries to the battery connects in the ups ??

Not sure UPS is up to running for a long time with larger bat, also charge circut might not be current limited and could overload with big battery hooked up

Re Simo and timers, Ive got a similar setup in mind, just trying to avoid those 12V delay on relays
I can get some used 240v delay on timers free but this means there will be tiny 240V demand (driving the relay) on inverter when it starts - will it be OK?

Jet is right. Smaller UPS are not current limited so the bigger battery if drained will attempt to draw far more current than the charge circuit is suited for.
Overheating due to running longer on battery is also a concern.

If the UPS is big enough to have the external connections for additional battery banks no problem, most of those are current limited.

I didn't like the ups idea either, not that iv looked into possible problems your reasons make sence. It also spells unreliability to me, I think the main idea of a bbu is to use the least amount of components, try to design it to be as simple as possible, and make sure it can handle the job. I also like the idea of an alternate source of running it for pro longed outages, ie being able to source it off a car.

I think weekly testing and monthly cycling is also important.