UPS/backup system for PC

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lucifir

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Hi guys,

I am looking at getting a UPS/backup system for my PC(incl monitor obviously :) ) at home, so that I can work during load-shedding ... anyone know of any good (and resonably) priced systems that can accomplish this??
I would also like it if it could allow me to run about 3 lights, the TV, and my adsl modem.

I spoke to the guys at smartpower and they want to give me a 500VA/Watt(not sure which one it is!!) unit, that they say will be fine for my PC and TV for at least 4 hours. So far, from what I read, that does not sound right ... as the other sites say that I would need a 1400VA unit. Anyone know about this and willing to shed some "light" :)

Also, this unit from smartpower seems to operate like a UPS, except it provides power for longer... which is what I want. They are costing it at around 4.6k ... is that reasonable??

any help in this regard would be greatly appreciated :)
 
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shadow_man

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Thats absolute bullcrap - i am going to be selling ups units soon and a 500VA will only give you +-15 mins for 1 pc/15" monitor - what you should do is get a cheapie ups e.g. 500VA and a generator - nothing short of a big corporate ups or some such for quite a few grand is going to let you run what you want for 4 hrs + . - 3kva gen is about R2k + 500VA UPS is about 500 - that would be your cheapest option I reckon.

J
 
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StillOnSent

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Intellipower 4 www.catsdigital.co.za
Its 2000VA with 2 105AH batteries


I run a PC, 20" LCD, Router, 72cm CRT TV, 18W CFL light, home theatre system, and a DVD player off it.

I have run everything together for 5,5 hours, with no sign of running out of power
Easily handles our normal 4 hour loadsheding schedule ( City power schedule )



Whatch out for cheap generators that dont produce clean power, and make a LOT of noise.
 
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The_Techie

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Hmmm, my UPS barely lasts long enough to power down my PC and it's a 600vA...
 
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StillOnSent

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Remember , its not the volt amps (VA) that determines how long it can last, its the size of the battery that determines run time

The VA is just howmuch you can run though it
 
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.Froot.

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Have a look at the total current running through your appliances (eg pc=3A, lights=2A, etc) and add them up. Then you need an UPS that can handle that amount of current through it. You calculate this with the following: 1400VA UPS means you can run 1400=(voltage)(current) through it, where voltage =230V therefore you can run 6amps through it. Don't use more than 5 amps, however, since an appliance, when you switch it on, uses about 15% more current than when stable, ie a 2A appliance will require 2.3Amps to start. Then secondly with an UPS, different units have different battery lifetimes, depending on the size of the batteries inside (average is about 7-14AH). This (taking 14AH as an example) means that it can run 14A for an hour, or 1A for 14H :)

So let's say you're now running the 1400VA UPS with 2x105AH batteries (BUY SEALED BATTERIES, THE OTHERS LEAK GAS, GO GOOGLE IT)(AND NOTE THAT THIS WILL VOID YOUR WARRANTY ON YOUR UPS) and you are running the following: PC, Screen, 3xlights, TV and ADSL modem. (500W PC->2.5A + LCD screen-->2A + 3x lights -->0.8A + router -->0.3A + TV-->~4A ) == 9.6A 2x105AH / 5.8A --> theoretical 22H of power. But this will be less due to energy dissipation through heat and chemical transfer. A safe method to work out how powerful the UPS should be is to say that 1400VA can only give 1400W of peak power therefore the Wattage of all those appliances should never exceed ie 1150-1200W for the mentioned switch-ons current draw. If you take a 300W UPS, the chances that you will be able to start a 300W PSU, is pretty slim, if not completely impossible.
 
adsl3g

adsl3g

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In calculating all this current, does anyone know how much a PVR uses. I can get all my other items watt usage except the PVR's is not mentioned anywhere in the documentation.
 
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StillOnSent

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adsl3g said:
In calculating all this current, does anyone know how much a PVR uses. I can get all my other items watt usage except the PVR's is not mentioned anywhere in the documentation.
Click to expand...

Look on the back of the unit
It should state the watts or amps
 
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.Froot.

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A PVR uses somewhere in the range of ~150W. Was mentioned somewhere in a thread in the last two weeks.
 
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lucifir

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thanx for all the info guys ... gonna get these smartpower guys to demo their product ... will let you know the outcome of the demo ....
the reason I don't want a generator ... is because of the noise ... the possibility of explosions... storage is also a problem .... and I don't want to be lugging around huge containers of petrol/diesel ... also ... I heard that it might be illegal to have a generator in your home(not sure how true that is!!)
 
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The_Techie

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adsl3g said:
Yep, thought so, its the hard drive. and there is nothing n the rear of the PVR nor in the specifications,
Click to expand...

Hard drives don't use that amount of electricity as far as I know. Most hard drives when idle use about 7W, jumping to a max of 30W when in use from what I've read. Could be wrong, though ;)
 
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.Froot.

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I do note your point. That was however what I read. Could have been wrong too. But that difference in power for the PVR won't (likely) crash an UPS :)
 
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StillOnSent

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adsl3g said:
Yep, thought so, its the hard drive. and there is nothing n the rear of the PVR nor in the specifications,
Click to expand...

Doesnt it state the volts where you plug in the power cord ?
The others state the Watts or amps there aswell
 
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StillOnSent

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froot said:
I do note your point. That was however what I read. Could have been wrong too. But that difference in power for the PVR won't (likely) crash an UPS :)
Click to expand...

I see the models on UEC's website that are similar to our PVR's state 0.8A

So they do use a lot of watts

At 220V 0.8A is 176Watts
 
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