How to go about picking out a UPS for your computer

[AlphaRapax]

I thought I'd write a basic how-to on picking out a UPS for a computer.

Now I am by no means an expert, I'm just throwing together what I know, and hoping with a little help, we can put together a UPS how-to

 

 

1. Understanding Batteries

 

Battery capacity is measured in AH or Ampere Hours, which the the amount of time power at a certain Current that can be drawn from it.

Note that Computer UPS Batteries are always at 12volts DC.

 

If you remember your basic physics you'll recall that Watts = Amp X Volt.

So a 10 AmpHour battery at 12 volts will theoretically give you (10x12) 120 watts for one hour at 12volts.

I say theoretically because, like all components, batteries are not 100% efficient, in fact they are usually 70-80% efficient. Which means instead of 120 watts for one hour, you'd get (120*80%) 96 watts for one hour.

This simple equation is flexible, so 96 watts for 1 hour, could be stretched to 192 watts for half an hour, or 48 watts for 2 hours, if you go the other way.

 

So in theory,

An average 7AH battery could give you [(7x12)*80%)] = 67 watts for one hour or 268 watts for 15 minutes.

 

 

2. What is VA

 

Volt-Ampere (VA) is a measure of power in a DC circuit. It's used on occasion with AC circuits but is less precise there.

Simply put when picking out a UPS for a computer. Multiply the VA rating of a UPS unit with 0.6 to get an estimate of what wattage the UPS can support.

So, if you have a 600VA unit which is about average. Then, (600*0.6) = 360.

Meaning an average 600VA UPS can support a maximum load of 360 watts.

 

The other way round. multiply the watt consumption of your system by 1.67 to get an estimate of what kind of VA you will need.

So a 360 watt system, (360*1.67) = 601 VA.

 

 

Hope this little guide helps.

[ALPHA17]

Good stuff, will give a good reference for people who want to purchase UPS for any purpose.

 

sent from miG

[AlphaRapax]

From one Alpha to another, thanks man