Backyard Aquaponics
A place to discuss aquaponics

What sort of air pumps does everybody here use. I have been looking at the various size Resun Electromagnetic air pumps that are advertised on ebay. The smallest and therefore least power hungry one has the following specs:

Voltage: 110/220/
Frequency: 50/60hz
Current (<A): 0.2/0.11
Power: 10watts
Pressure: >0.020Mpa
Output: 30L/minute
Spec.of Divider: 4
Size: 180x95x115
Weight: 1.0Kg

Reason I am interested in the power drawn is that I would like to run off a trickle fed battery, so taht if the power goes off then I will still have air for a number of hours.

Would this 30l per minute be sufficient for a decent sized tank with good stocking rate. Of course when the water pump is running, it would be supplemented by the oxygenation caused by returning water. But all the same want to get a pump that can sustain fish in air with just the air pump going if need arises (or if I want to cycle the beds off at night).

I know that some of the air capacity would be lost due to the stone being uder water, but I guess it would not be necessary to always place it at the very bottom of the tank if the tank is quite deep??

VB,

That is the exact same specs my BIG pump has.

I think i payed it around $100. has been working 24/7 for about 3 years.

PLENTY of grunt the model number isn't MAP30, is it? if it is then its the exact pump i have.

I used it to keep around 20 perch alive in only 165 Litres.

Worked a treat! For that size they rec. having 4 large stones connected via a 1 to 4 outlet manifold. This helps reduce back pressure and increases pump life. each of my stones are just smaller than a tennis ball.

Besides it will probably have an 8mm outlet and the stones are 6mm tube (i think)

The 1 to 4 manifold has an 8mm inlet and 4x 6mm oulets. Its just a little nylon thing.

Hope this helps

Steve

just found the one you were talking about on ebay. looks basically the same as mine. highly reccomend.

And it says its piston & cyclinder, so no rubber diaphragm to age and tear.

Yep, I agree with Steve, looks like an ok pump, and the specs would suit your purposes no worries... Of course you just never really know about how long they will last untill you try them out.. I did have a resun pump a lot like one of these these but with 4 outlets. It only lasted about 12 months...

This touches on the previous discussions regarding backup power, but can anybody tell me what I would have to do to get a pump like this to operate of a battery that is in turn being topped up by my 240V. If te power did go out, how long would a pump with these specs run for. Is it even possible to run this pump of a battery - it is AC not DC and is meant for 240V eventhough it only draws 10W.

I'm not good with electricity. I do however want to make sure my air pump setup keeps going for a reasonable time in case o blackout - which we are bound to get here at least once a year after a severe storm.

Hi VB,
You could run it off a small inverter which would draw it's power from a 12 volt battery which is in turn kept charged by a battery charger from the 240 volts power supply......or get one of those UPS units (uninterrupted power supply) You can buy them at computer stores and similar places. If you are an eBay lover then I am sure there would be some on there.
Murray

Thanks Murray. Would prefer to go with the charger to battery to inverter to pump option. Looked on ebay and can see that would not be too expensive to buy a small inverter. Will try and pick one up from a shop if I can to avoid the ridiculous postage placed on these on ebay.

Thanks again.

Would this be a suitable inverter.
http://www.jaycar.com.au/productView.asp?ID=MI5102&CATID=&keywords=inverter&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=

Would go for this next one, but would have no idea how to do what I had to to turn it into what I needed. Better off spending the extra bucks I suppose and have it all ready made and packaged.

http://www.jaycar.com.au/productView.asp?ID=KG9006&CATID=&keywords=inverter&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=

VB,

Go the first one.

1) becasue you would still need to buy a transformer for the second kit (i assume you don't have a scrap bin full of them like me )

2) becasue the first unit has modified sinewave output. While not perfect, it more closeley matches the normal wall supply than "square wave" which the second kit is.

It seems fairly good and has low stand by current (300mA which works out to under 4Watts)

I've done the calculations for you with the 10watts that the pumps draws and the 90% efficiency of the inverter. You need to buy a power supply that can supply at least 1 amp continuous for the battery. This would keep the battery charged while running the pump.

I'd go for this charger. it will supply upto 1.8 amps which is good in the sense that if you have a power outage, and you battery becomes almost drained then it has enough output to run the pump AND charge that battery back up from scratch when the power comes back on.
http://www.jaycar.com.au/productView.as ... &SUBCATID=

or you could use this one
http://www.jaycar.com.au/productView.as ... &SUBCATID=

but at 1 amp there is less that .1 amp left over from what the pump takes, hence only really enough to keep the battery topped up. you would almost certainly need to disconnect the pump to charge the battery if it ran down during a power out (and having to disconnect the pump at any stage sort of defeats the purpose )


And i would suggest using this battery, it will last over 5 hours running that pump, possibly 6 hours.
http://www.jaycar.com.au/productView.as ... &SUBCATID=

Hope this has helped.

Steve

Hi VB
The price of inverters has dropped a lot in the last couple of years, it used to be about one dollar per watt. (200 watt inverter was about $200.00 - 2000 watt inverter was $2,000.00 to buy)
I have mucked around a lot with inverters in boats over the years, powering microwaves and other onboard equipment and as a rule of thumb it pays to buy an inverter that has at least 50% more capacity than you think you need. You will always find other things to be "pluged in" and the "watts" output quoted are obtained in the factory under ideal conditions - whereas "field" conditions are often less than the ideal found in the factory or lab where the rating calibrations are done.

On battery chargers, there are also a good selection to be found in Super Cheap / Repco stores.
Best to by one that has much more capacity than you think you need as you will connect more things to the system as time goes by.... water heaters bubblers etc.
I got a B/charger from Super Cheap a couple of months ago for 59.00 - 7 amps max and 4 amps continuous output
Car batteries are also not that expensive - 40 amp hour for around 70.00
I reckon it is the way to go with everything on the system personally.... However, it is a bit like choosing a wife, everyone has a different preference/opinion... just as well !!!
Later on as funds allow one could expand the battery bank and add solar panels to make the system very reliable.
As Steve has pointed out, you need to allow some watts to be lost just in the inverter doing it's thing.
Murray

Thanks Murray and Steve - you are both a wealth of knowledge.

I can see the benefits of spending a little extra so that I have the option of adding something else t the system or getting a higher watt pump.

Are there any disadvantages of using a car battery rather than one of the less powerful sealed type units that Steve has pointed out? On the face of it, for the difference in money compared to difference in capacity, it seems that the battery and charger that Murray has referred to may be a better option, particularly if I want to expand at som time in future. Of course this would be bigger, heavier and ugglier, but this is not a problem for me as I would just be stashing it all in my shed anyway.

Vb,

I was originally going to suggest using a small 4 cycl car battery as it is far cheaper than the sealed type (per amp/hour capacity). Only One thing to really watch out for is that CAR batteries are NOT designed to be "flattened" i cant remember the exact figure, but its been quoted that around 20% to 30% of battery capacity is lost by running them down.

This is demonstrated in everyday life, have you noticed that when ever you leave your lights on and need a jump start, that the battery is never quite the same? after a few months you end up going out and buying a new battery

A normal car bettery is designed to be able to supply upwards to 300 amps for a few seconds to start the car and then its topped up by the alternator.

There are other types called "deep cycle" or sometimes "recreational" mostly used in boats and by campers. they are designed to be "cycled", but they are much more expensive than a normal car battery.

Having said all that, you're not expecting the power to go out on a regular basis, so its not so much of a concern! Just thought i'd highlight it.

Also if you're not looking for much more than 6hrs back up then the SLA battery i linked to is a good buy for around $25. but if you're looking for more than that then a cheap car battery at $50 will give you 24+ hrs.

PS if you are going to use a car battery then buy a battery charger like murray suggested, the smaller ones i linked to won't cope on such a big battery!

Hmmmmmmmm to many choices. have fun

Thanks Steve.