UPS for air pump

[SynoSteff]

Hi there,

I am interested in getting a UPS to power my air compressor when the power goes out untill I can get there and turn on the generator. How do I know what size UPS I should get and how long it would last for. My compressor is 70W.

For example if my UPS had an output of 210 Watts / 350 VA what does that mean? or 300 Watts / 500 VA ?

Thanks

[LesbianChap]

From: http://www.powercom-usa.com/techsup/faq.html

How do I determine what size UPS to get?
UPSs are sized by their volt-amp (VA) load. To calculate the VA load of your system check the UL label for the operating voltage and amperage drawn. Add the amperages of each component to be powered by the UPS and multiply the number by the voltage (120V for US applications). This number is your VA load and the minimum size required. It is good idea to size your UPS at least 30% larger than the minimum VA load to leave room for future needs.

From APC (http://nam-en.apc.com/cgi-bin/nam_en.cfg/php/enduser/std_adp.php?p_faqid=1356&p_created=1010390400&p_sid=eCn_46Zh&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX 3Jvd19jbnQ9MjYmcF9wcm9kcz0wJnBfY2F0cz0mcF9wdj0mcF9 jdj0mcF9zZWFyY2hfdHlwZT1hbnN3ZXJzLnNlYXJjaF9ubCZwX 3BhZ2U9MSZwX3NlYXJjaF90ZXh0PXNpemU*&p_li=&p_topview=1)

This document explains the use of non-computer type loads with APC's Back-UPS Line.
APC's Back-UPS line is designed for use with Computer-type loads only. They are not designed to be used with motor loads such as fish filters, air conditioning units, space heaters, vacuum cleaners or any other machinery.

One potential issue is the inrush current draw for a motor. It can easily overload a Back-Ups UPS model. Secondly, these models of UPSs output a Stepped-Approximated sine wave when on battery. This waveshape, while ideal for computer-type equipment, is not particularly compatible with most motor loads. The result may be that motor runs very slowly, erratically, or not at all when the UPS is on battery.

To protect this type of equipment, APC recommends first determining the appropriate size UPS for the motor load in question. Ensure that the Volt Amp rating of the UPS is sufficient to handle the start-up inrush current draw of the motor. Secondly, select a UPS which outputs a Pure Sine Wave when on battery, such as a Smart-UPS (minimum of a SU700), Matrix-UPS, or Symmetra Power Array.

Hope that answers at least one question for you.

[SynoSteff]

sheesh ... not as easy as I thought :(

****

Thanks for the info tho

[Soulcoffr]

The biggest problem you'll have getting a UPS for your compressor, is that most UPS units sold are for computer equipment and are not rated for use with electric motors. They can't handle the sudden current draw and possible line harmonics that AC motors can dish out. The UPS units that can handle it are, from what I understand, prohibitively expensive.

Sounds like an automatic battery operated airpump is what you might need as a stop-gap between the grid and your backup generator. They're just little airpumps that detect a loss of grid power, and start pumping air for oxygen exchange. Some run on D batteries, others on NiCd.

Here's an example:
http://www.petsmart.com/global/product_detail.jsp?PRODUCT%3C%3Eprd_id=84552444177 9314&FOLDER%3C%3Efolder_id=2534374302030044&ASSORTMENT%3C%3East_id=2534374302023693&CONTENT%3C%3Ecnt_id=10134198673326210&bmUID=1136740096396

[SynoSteff]

Yeah. This is rather unfortunate. The problem is that I need to keep the air running in 8 large (1.2meter) tanks. A UPS for my compressor would have been perfect. But i guess i'll have to try something else.

Is it not possible to get bank of batteries (car batteries) and then have an inverter on them going to my pump and then get a mains charger for the car battery bank and have it on continously. Dont know if you can leave them like this tho. Dang. What a mission. HeHe

[Soulcoffr]

Yeah. This is rather unfortunate. The problem is that I need to keep the air running in 8 large (1.2meter) tanks. A UPS for my compressor would have been perfect. But i guess i'll have to try something else.

Is it not possible to get bank of batteries (car batteries) and then have an inverter on them going to my pump and then get a mains charger for the car battery bank and have it on continously. Dont know if you can leave them like this tho. Dang. What a mission. HeHe

Wow. I figured you probably had a pretty big setup to need a compressor like that.

The problem with the car batteries is that might work, but then you have maintenence on all those batteries, plus the problem of hydrogen buildup and all the other issues that come with a large bank of lead-acid batteries. I'm sure you could make a nice DIY project out of it, but it'd be a lot of work...

[SynoSteff]

hehe. Yeah. I have recently got a whole broodstock of synodontis. Already managed to spawn my Nigriventris (zebra variety) but none others yet. Some are still growing up. I've lost 2 beatifull, large S. decorus and 1 large S. brichardi due to power failure and that's why I am trying to get a UPS ;) hehe

I recently got my alarm guy to get me an old alarm system, which calls my cellphone in case of a power failure, which is great. Also, have a small 2-stroke generator as a back up. I live half an hour away from my fish room tho so a UPS type thing would be perfect to keep it going if i get delayed or something goes wrong. The decorus and brichardi are expensive and sensitive :(

I'm sure we'll work out somethin eventually. I hope. So happy with my alarm too. Was pretty cheap. About $120

[Roan Art]

You could look into buying a generator. An electrician can hook one up with a transfer switch to your power box that will supply power to your fish room when there is a failure.

We have one that runs the entire first floor of our house.


Roan

[SynoSteff]

I have a generator but it's a pull start not an electric start so it has to be done manually :( Those electric start ones are really expensive here in RSA

[Roan Art]

Ack, sorry, didn't realize you were in SA.

Might be worth it to have someone "on call" that can start the generator when you're not available.

I'll ask my husband when he gets up (taking a nap). He may have some ideas for you.

Roan