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KennyF

Camiguin has its fair share of blackouts so I'm thinking of buying a UPS that will run a fan and a few low powered things like cell phone chargers.

 

How do I work out power needs?

Say my fan is 100 watt. How long will it run on a UPS rated 1200VA?

 

KonC

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Paul

Before I get started here Kenny, remember - YOU asked. :D

 

The short answer is, and I am just guessing at the UPS efficiency here, I would say 2.5 to 3 hours, at high speed - a 50 watts draw on the UPS.

 

Here is the long answer:

 

VA is a cheap way for a manufacturer to make it's units "sound" as though they are more powerful than they really are. VA ratings are completely dependent upon PF (Power Factors). Here is an article I found that may help explain it a bit more: What is the difference between VA and Watts?

Most stand fans, 400mm (~16"), will draw about 45 to 50 watts. I have one here next to me that is rated at 50 watts, in fact. 

So, you have a 1200VA UPS. Realistically, it will only be about 70% of the VA rating, which would make it about a 700 watts rated UPS. It should have two internal 7 AH batteries inside, probably wired in series. So, this will be a battery of 24VDC, at 7AH. Of course, you also have to consider efficiency of the UPS. Unless you are going to put money out for a quality unit, like an APC UPS (which are manufactured in the Philippines, by the way), Lord only knows what type of UPS you will end up with. 

 

Going by the battery rating alone,  you can use the formula below to get a general idea of the rating of a UPS. (You have to know the specs and configuration of the batteries inside the UPS, first.)

 

Formula: 

Battery AH rating X Battery Voltage X .70 (efficiency) = WH (energy available)

 

 

Personally, if I were going to buy a UPS, and APC were available, that would be THE unit to buy. I have run them for years with no problems. 

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thebob

The obvious answer would be to not use a ups but to get a 12V fan and a battery and a battery charger! Then you can use a car charger for your cell phone.

Edited by thebob
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Paul

What would be the largest 12vdc fan you could buy in the Philippines? 

 

To extend the run time of a UPS, he can also do what I did - add an external battery to it. 

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Knowdafish

 

 

What would be the largest 12vdc fan you could buy in the Philippines? 

 

Answer: A 12v radiator cooling fan which moves a lot of air and cools very well but is extremely noisy. 

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KennyF

The one I was considering is from CDR King in CDO.for 2,999 pesos.

 

If I could get 3 hours of fan I'd be happy.

 

LINK

 

KonC

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Paul

The one I was considering is from CDR King in CDO.for 2,999 pesos.

 

If I could get 3 hours of fan I'd be happy.

 

LINK

 

KonC

 

This is merely my advice, so do with it as you wish.

 

But, you could pay about the same for an APC unit and it would be much better quality, I am sure.

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KennyF

Yes sure, but all I can find is an APC 1,100 VA for 8,995 pesos (nearly 3 times the price),

 

HERE

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thebob

 

 

What would be the largest 12vdc fan you could buy in the Philippines? 

 

I've got a 12cm brushless fan striped from a dead computer PSU here that is 1.8A. Delta AFB 1212SHE. It can almost lift itself it is so powerful! Recycling old computer fans is the best option for a cheap system like this.

 

The old emergency lights with a 2ft fluorescent tube are discounted these days because everyone wants LED... the power supply and battery is good for a system like this and it starts automatically and charges automatically when the power goes off. You can also add a bigger battery.

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Personally, if I were going to buy a UPS, and APC were available, that would be THE unit to buy. I have run them for years with no problems.

 

Personally I'd steer clear of APC unless you want to spend lots of money on the associated APC hardware to support it. I used to like APC until I bought one to protect my NAS, because both boxes had the signalling connectors so the UPS would shut down gracefully when power was off. Of course, APC only works with other APC hardware,  Their response was that I needed to buy their much more expensive hardware to get that feature to work. These companies that try to force you to buy their hardware by hiding the signalling protocols should be avoided at all costs.

 

Most hardware out there used nut software, from http://www.networkupstools.org/ to communicate with the UPS. They have a compatability list that shows which manufacturers are publishing the specs for their UPS's here: http://www.networkupstools.org/stable-hcl.html Withing the list they rank the manufacturers by how much info they have provided to allow the product to interface with other products. At the top there's a 1-5 star chart that corresponds to the colors in the list.

 

I sure wish I'd found this before I wasted money on the APC boat anchor.

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Paul

What "hardware" does a basic UPS have to use?  :rolleyes: Don't make mountains out of mole hills.
 

Below is a Back UPS ES-500. I had three of these at one point. The batteries lasted for several years, and I didn't have to run ANY other hardware with them. The ONLY thing I had to do when using them, was to plug them in, power them up, and plug my computers and monitors into them. 

 

apc_ups_01.jpg

 

Above and beyond the simplicity of using a basic BACK UP UPS, ACP is one of, if not the top company name in uninterruptable power supplies.

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lopburi3

If you buy by mail order make sure the outlets are what you want - APC makes both IEC plug/sockets and various normal outlets so if you do not see the back you may make a mistake (as I did) with this model which seller showed front only but when received found I had a problem.

BK500app.jpgDEB9C746-5056-AE36-FE7333228C102B45_pr.j

Edited by lopburi3
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