# A Question Regarding UPS Use

I have a question regarding the use of UPS to power my ADSL WiFi Router (15VA), it is vital for me to be online at specific hours of the day, right now I am using a Chinese brand UPS that gives me not more than an hour of backup, and that's very less considering my use and urgency.

I am thinking of buying this APC UPS brand new: APC Smart-UPS 750VA 120V UPS System : Power, Cooling & Data Center Infrastructure | Dell

I know the USP is expensive, but so is the work.

My question is how much backup time (estimate), will this APC UPS (750VA) give me? What-if I go the extra mile and buy this one? APC Smart-UPS 1500VA LCD 230V : Power Accessories | Dell UK the backup time will double?

Also how long will the battery last, I mean before I have to change them again?

Visit APC Website

Locate the model you want ..

See their graphs of load vs backup time

I just tried to do that, its asking for the watts, how much is 15VA in watts?

PS: did a Google for this, all I got were formulas I can't understand.

you measure the amps from one of your your main wire, preferably red wire, using a clamp voltmeter,..

the assume the voltage to be 220V as per standard.

you multiply the 2 to get watts

eg...

Assumiung it is 2.9 amps as on the meter

2.9 x 220= 638Watts for that appliance.

[quote=", post:3, topic:18987"]

I just tried to do that, its asking for the watts, how much is 15VA in watts?

PS: did a Google for this, all I got were formulas I can't understand.

[/quote]

Value in Watts for a certain VA depends upon the type of load (actually the load's Power Factor).

For a power adapter of ADSL modem, you can safely assume a power factor of 0.6

Watt = VA x Power Factor

Thus your 15VA would come to 15*0.6 = 9 Watts

Thank you guys, that helped!

waqas, could you tell me if you have a contact for an authorized dealer for the new apc ups? and how much they're asking for the two models you're considering? i tried reaching out to apc's sales team in pakistan but they said they don't really deal in household level systems, only in larger corporate setups.

thanks. would really appreciate your help.

to ijaz and farhan - new to these forums, landed up here because i'm desperately searching for a solution to the loadshedding problem. this was the only place i could find with actually decent information and the two of you have a lot to do with that. just wanted to say thanks.

thanks for help

To update on the topic.

I did not buy that APC UPS but bought one from AliExpress. This one: http://www.aliexpress.com/item/High-Quality-Mini-2200mAh-UPS-Battery-DC-5-12V-Support-CCTV-Camera-Modems-Routers/583392208.html

It is a 2200mAh UPS and lasts about 2 hours.