Uninterruptible Power Supply

Help!

We've been having problems with our electricity supply for over a week. We had no power at all on Saturday, and today it keeps dropping for a second before firing back up. It's already damanged my surround system, so I'm really p*ssed off now.

My question is... Can you get a UPS for home applicances? I've been googling, but all I can find are UPS devices for PCs. I want to protect my home applicances before it ends up costing me a fortune to replace them.

I'm not all that familiar with UPS devices, but can't you simply use it with any electrical appliance, not only PCs? I mean, it's basically a big battery that has outlets for plugging into.

Can't see why not. It'd just be a matter of wattage. As long as your appliances don't draw more than your typical PC setup you should be fine.

- David

Thanks for the help.

This one looks ok - http://www.ebuyer.com/product/46610

How can I work out how much power my appliances are drawing?

I have a CRT TV, a Wii, a Sky+ box, a DVD player and a surround AMP (once it's working again) in the living room. Should this UPS be sufficient?

Check the devices and add them up.

I have used Smart UPS RM-750`s before and they have an LED indicator on the front to show the "load" being drawn by the plugged in devices - from this you can also gauge how long it will supply power for before shutting down.

However, most UPS take kettle leads as the power inputs, so unless you get a converter or rewire yourself (dangerous) - I¬m not sure if there are UPS for plugs, but as I say I got around it by rewiring the device.

These arent meant for sustainable power when your supply gets cut off - they are meant for allowing sufficient time to shutdown / turn off the devices safely without and damage - thats why they are used on servers a lot.

That one certainly doesn't have normal plugs, but I don't know about "most." The photo on the wiki page shows normal plugs:
http://en.wikipedia.org/wiki/Uninterruptible_power_supply

I don't know how it is in the UK, but in the US computers generally have normal plugs, so a UPS with those funky sideways plugs (kettle plugs you call them? the first time I'd ever seen them was when I moved into this apartment this summer, because the AC uses plugs like that) would be pretty pointless. Obviously you wouldn't want to buy a UPS from this country though because of the frequency.

I know people often use them to buffer sensitive audio equipment from power flucuations (ie. exactly what milky joe described.) Milky Joe, I'm thinking you don't need to plug all of those into the UPS because they aren't as sensitive as an amp. The CRT TV for example.

800VA is very little.

I was recently looking at UPS's myself, and I found a 1285VA one for my PC which was $165:

http://www.staples.com/webapp/wcs/stores/servlet/StaplesProductDisplay?&langId=-1&storeId=10001&catalogId=10051&productId=148360&cmArea=SEARCH#desclink

Thing is, even one like that doesn't last that long. They advertise it as "up to 145 minutes" but that is for a certain Mac which is really power efficient. For a PC, I think you get like 90 minutes if you have a tiny LCD screen, and if you have a 24" LCD screen then you're looking at only 45 minutes. And a CRT, a SMALL one, like on a PC, then you're talking like 30 minutes maybe. But a big TV? And a surround sound system? Hell no that UPS isn't sufficient!

In addition to the run time, there's probably limitations on how much juice you can draw on it before tripping the fuse. So... look at the back of your devices and figure out how much wattage they need first. I think you're gonna be spending a pretty penny to run all that stuff off a UPS though. But check amazon they have good deals sometimes. Maybe you can get something for $300 that will do the job. :-)

45 minutes? How long does it take you to shutdown your PC? Are like a three mile walk from the plug? As Rik said, these things are only there to smooth out brownouts and give you a chance to shut down if it's a black out. 15 minutes should be ample.

EDIT: Oh never mind, I think I misunderstood. I thought you were saying it wasn't good enough for you either.

Gabriel:
Yeah, what I'm saying is that UPS won't last five seconds. :-) You need at least five minutes to save files and shut down.

If all you want to do is smooth things out, then get a surge protector. It won't stop brownouts, but I doubt too little power is what caused his thing to short out.

Also -- keep in mind that you can't run all kind of appliances of a UPS -- if you plug in a spaceheater or microwave, expect it to kill the UPs rather than protect the appliance since they draw more power when in use than the UPS can realistically provide.

Which is why you'd need to tally the appliance wattage and compare that against the UPS power rating. Normally appliances have a sticker on the back that let you know their peak draw.

Worst case scenario: I imagine an electrician would have the equipment to measure the combined load fairly accurately.

You need a petrol driven generator with about 2500watt output minimum (for good 2/3's fuel efficiency) for power failures. The UPS stuff won't do diddly for you - they're all over-rated. I use a generator for power-cuts which happen about every 3 months where I am, and can sometimes last upto 2 weeks in winter if there has been a bad snow storm. Either way you'll need to stock up on petrol. I get 11 hours for 15 litres giving 1600watts constant..enough to be able to work and have lights and watch the TV, keep the fridge alive etc.

Thanks for the help.

I mainly want to protect my applianaces, rather than have them keep going up and down when the power fluctuates. I just want enough time to turn them off really. I already have surge protectors in place, but my surround amp still got damaged.

I do like the sound of a generator though...

Just so you know (I didn't read all the posts so apologies if someone mentioned this already), but the formula is P=IV (Power = Current * Voltage)

so a device that uses 3 amps at 16v consumes 48 watts (0.048kw) of power

(This is one of the few things I remember from school :) )

Most things say the wattage on the back.

P=IV means:
Watts = Amps * Voltage

This wikipedia page has some useful information:
http://en.wikipedia.org/wiki/Uninterruptible_power_supply

For example:



If you read that page it might help you. It appears there are outdoor UPS systems you can get which may provide the amount of wattage you want. But I'm sure they're not going to be cheap.

Anyway the above quote seems to answer the main question. Look at the VA rating on your power supply, (VA is another word for Watts. Volts*Amps = Watts, remember?) and figure out the wattage of your appliances, and then get a power supply which is at least 1.2x that. I don't know how much runtime you get if you leave only 20% wiggle room, but it's probably not much, seeing as a 1200va supply will only power a PC consuming maybe 500 watts for 30-45 minutes. And that's assuming I think that the PC itself doesn't draw 380 watts all the time. Probably draws a lot less when it's not doing much.

and with the right drugs or 'tyres' from spaced's attitude you can get a pretty good groove going :))

He he - yeh! Quiet they ain't.

trust me ... i found the right spot @ work to really enjoy the sound of our fire alarm (after we'd been given the ok to go back in) ... splashing over tiled walls echoing here and there

One Christmas I had just about had enough of my wife and went to sleep at my work place in the centre of Manchester. I opened the door only to realise I'd forgotten the alarm code. I spent two days of insanity there with the siren going non-stop until, one late evening another coder turned up and rescued me. The look on his face when he saw through the semi-darkness that 6 weeks-worth of newspapers were taped all over the alarm box!

I had to hide from the police too...ah! Fun days.

[slightly off topic]

I once inherited a very old, very heavy UPS which was the size of a small fridge.

I played "plug in a kettle and boil water" with it.

That is all.