UPS, what VA do I require?

Mr. Flibble

I have an external hard drive (3.5", no fan) and I want to get a UPS for it. Does anyone know what power UPS I should get, and about how long would it provide power to the harddrive if the power fails?

Also, about how many years would a UPS device last before the batteries die?

Would something like this suffice?

ethernet

It depends on what you're connecting to it. I found this link on a wikipedia entry. It may help you calculate the rating you'll need.

I had a look at that manual for that model [750 VA]. It seems that can handle 450 W. Is this really enough? Your PC's PSU could be this alone. Throw in an LCD [60-100 W] and other peripherals. You *may* want a higher rating.

Mr. Flibble

I'm just connecting it to an external hard drive. I'm using an old laptop as a server which comes with its own UPS so its just the HD that needs power backup.

Does a higher VA translate into longer up time in the event of a power cut?

Thomas_S_Hunterson

Mr. Flibble wrote:

Does a higher VA translate into longer up time in the event of a power cut?

As far as I know, VA is the product of Voltage and Current, and is therefore the same as wattage. It relates to how much power the UPS can provide.

Mr. Flibble

sean_keevey wrote:

As far as I know, VA is the product of Voltage and Current, and is therefore the same as wattage. It relates to how much power the UPS can provide.

Ok. So higher VA doesn't mean longer power.

I've an honours degree in electrical engineering, lol :rolleyes:

Capt'n Midnight

Find out what battery is in the UPS
eg: APC smart UPS 1000
12V x 7Ah x 2batteries = 168Watt hours

12V ( aveage - they discharge from 13.8 -11.8 )

real world guesstimate
168Wh * 70% efficiency = 120Wh

work out the power of the drive and divide it into what ever your UPS says.

Mr. Flibble

Coo, cheers Capt'n.