14 replies to this topic

[bobby dazzla]

Hey all,

I am wanting to bulletproof my tanks in the event of a black out and after reading a bit on this forum it looks like keeping the air pumping is more important than the filter. So i am just wanting to get some pros and cons and see what other people are using.

Option 1: Buying a UPS unit and running my air pumps off that. Should be good for many hours but never had UPS and not sure on the life expectancy of the battery in the unit.

Option 2: Buying an air pump that runs on mains power with a battery (4xD size batteries) back up. Have found a US brand Penn-Plax that fits the bill but will require a voltage converter transformer (If anyone knows of a Aus one i would be very interested). But if the batteries die in a few years time it is cheaper to replace D size than a full UPS system.

Air Pump:
http://cgi.ebay.com/...=item5889e4efc5

Cheers

[werdna]

Aquotix had some battery backup airpumps before.

If you get a ups make sure it has a pure sinewave inverter, not modified sinewave, as a standard airpump wont work properly otherwise.

The batteries in a ups are generally the 12v 7ah sla battery used in alarms etc. You can generally get them for around $15 if you shop around.
You should get atleast 2 years out of the battery before it fails.

[bobby dazzla]

Thanks for that Werdna,

The batteries for $15 for the UPS is very appealing I thought they would be alot more expensive than that. I didn't know about the difference sinewaves so glad i posted here before buying one off eBay.

Seems the no name modified sinewave UPS are available for about the $200 mark while a no name pure sinewave is about $500 delivered. The blurb i read said that Pure is alot more expensive than modified and is better suited to sensitive electrical equipment. Never thought of an air pump as sensitive ... do you know the reasons they don't like the modified sinewave ?

Leaning towards UPS means i can be more selective with what air pumps i run, but does make it a more expensive option.

[Den]

I was talking to Kevin/Synetrix about organising a group buy for some UPS, this is one I use in my fish room below, havent tested it on airpumps yet, but it keeps my 110W sump pump going for about 43minutes so I figure a it could keep 5-10watt airpumps going for a long time?

If anyone knows of a better one thats cost effective we should organise a group buy, Id like one at least twice as powerful as this one if possible.

POWERWARE UPS 3105 700VA

http://www.i-love-pc...?ProductNO=2628

[bobby dazzla]

Yeah i would be interested in a group buy, will keep searching for a reasonably priced pure sinewave in Australia.

That little unit looks pretty good for $88 though Den, I am assuming it's modified wave. Would be interesting to see if there is a noticable difference when you run an air pump off that as opposed to the mains.

If you do a test though use a cheap air pump i would feel bad if you fried a good one

[Den]

It did make my water pump run a bit slower and it got more noisy but it did the job, I think Kev uses them for a bunch of things, now that you guys mention it Im not going to risk my schegos until I get some educated advice, so Ill wait for Kevs or Andrews reply.

Cheers
Den

[Kieran]

Aquotix still stocks the battery backup airpumps. Easiest option. They run at half power on battery, for hours and hours.

A UPS will work just fine. Go for a name brand one, not a cheapie. As stated above, a decent UPS will supply a relatively clean waveform on 240V AC, wheras a cheap one you may find produces a dirtier waveform. I couldn't tell you what the real load of an airpump or filter is, but even small VA models such as the one Den suggested above (a 350-700VA model) will be adequate for running airpumps.

A DIY alternative is a sealed lead acid battery (from BCF or Battery World, etc) and an 12V->240V inverter from any camping shop or bunnings. This will give you a larger backup battery to work with. Again, buy a quality inverter that produces a clean waveform and you shouldn't have any problems. Using a normal 40AH car battery you should be able to run a 5W airpump for days, or a 25W eheim cannister for about 12hrs, after losses in the inverter.

[werdna]

Modified sine wave top, pure sine wave bottom

Modified sine wave works fine in almost any device that uses a switch mode power supply. That is because the first thing they do is go thru a diode then capacitor to make 340v dc, then the power supply is switched on and off at the speed required to get the power needed for the device.

Air pumps dont use switch mode power supply's, they go straight into a transformer and use the shifting ac waveform to alternate between north and south magnetic poles (making an electromagnet), then making a magnet connected to the diaphram moves side to side.
A transformer cant handle modified sine waves.

You will find that if it works, there will probably be quite a scary buzzing noise while it is running and the airpump will get hot.

Edited by werdna, 04 April 2011 - 07:02 PM.

[Den]

Topic shifted thanks

Edited by Den, 04 April 2011 - 09:02 PM.

[Kieran]

Air pumps dont use switch mode power supply's, they go straight into a transformer and use the shifting ac waveform to alternate between north and south magnetic poles (making an electromagnet), then making a magnet connected to the diaphram moves side to side.
A transformer cant handle modified sine waves.

Interesting. Thanks for that I didn't think they were that basic.

It would be best to run your airpumps on a clean waveform then, or at the very least whack a decent load on the inverter to help smooth out that modified sine wave.

[Den]

Andrew that might explain my sump pump making the buzzing noise? but it kept working, Im guessing because its underwater heat isnt an issue?

is there any way we can safely get airpumps working on backup battery supply/UPS?

Edited by Den, 04 April 2011 - 09:04 PM.

[werdna]

Buzzing noise when on a ups/inverter? If it doesnt when on mains then that will be the issue.
It will probably be less efficient as well, but if it is only when you have a power cut then that isnt really a problem.

In theory if you put a coil in between inverter and pump you can minimise the effect, but you would need to know what you are doing so I wouldnt recommend people trying.

[bobby dazzla]

Haven't managed to source any cheap/quality pure waves UPS yet will keep looking when work is quieter. Will try to ring aquotix in the mean time and see what they have in regards to the battery back up air pumps, may be a good short term alternitive, or may turn out to be a perfect solution.

Cheers for all the feed back

[Ivan Sng]

I think you need to firstly work out how much air you really need on loss of AC power, and of course also for how long...

Some small stand-alone AC/DC air pumps will last for almost 10 hours but if you have a few tanks, you will not have enough air to run them all... A UPS is probably in the similar situation, although you might have a bit more in the UPS to power bigger air pumps...

If you have a fish room, I would suggest going down the path of the 4WD battery... via an inverter. For an air pump, I don't think you need a pure sinewave inverter...

For my outdoor tanks, I have put together an AC switchover panel. The air pump (an electromagnetic one) is normally run off the mains AC, upon loss of power, the relay inside switches over to the 12V battery line which feeds through an inverter and hence powers the same air pump. A smart battery charger constantly keeps the 4WD battery charged.
This setup has served me well in keeping almost 30 plate size barramundi alive for 10 hours during the last freak storm we had in Perth... The air pump is a 70lpm pump...

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[golden_dase]

There is now a cheap UPS product with pure sine wave output. They range from 500VA/320W to 1400VA/950W.

More info here: http://powerquality....specs.asp?CX=22

At the bottom of that link is a "runtime" chart which shows how long the UPS will power your preferred devices. Please note that the chart is based on FULL LOAD. So if you're using a 10watt airpump, you can be guaranteed that the battery inside the UPS will last a lot longer than shown on the chart!