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General

10/11/2008 2:51 AM

Hi all, I am looking for domestic UPS to be used during power cut in home. My question is what are the important specification to be assured during purchase of UPS (500 VA) to manufacturer ? also 500 VA (or) less VA is enough for 3 tube, 2 fan and a TV. please suggest me.

shreenandhu. Tamil nadu. India.
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SAK
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Engineering Fields - Power Engineering - Projects Engineer

Join Date: Aug 2008
Location: Tanzania- East Africa
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#1

Re: General

10/11/2008 4:59 AM

tHE IMPORTANT SPECS.

Voltage should match with the supply voltage

AH of the battry ,compared to your Ampere requirements, this will guide you to the duration the power will be available from UPS

Normal UPS have a battery capacity of 7 AH which means that it can give you at full load 7 Amperes for one hour before it flates out.

Now considering your load:(at 230 V)

3 tubelights =40w X 3 = 120 watts=0.5 A

2 Fans = 60 w X 2 = 120 watts= 0.5 A

1 Tv = 80 watts X 1 = 80watts= 0.35 A

TATAL LOAD IN AMPS= 1.35A

a healthy 7AH battery will last max 3/4 hrs considering the efficiency of the UPS inverter and startup surge.(for fans and TV)

you need to confirm the actual watts on your appliences and battery cap.this should serve as a guide only.

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indel
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#2
In reply to #1

Re: General

10/12/2008 2:23 AM

If you have a 230V battery, your calculations are close. What shall I do I, a poor guy, with a 12V battery? How many hours seconds will the charge last?

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ducon
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#3
In reply to #2

Re: General

10/12/2008 6:22 AM

Stop complaining. I just have a pen-light cell!!!! help me.

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indel
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#4
In reply to #3

Re: General

10/12/2008 9:16 AM

Talking about cells; for my HP13 hand calculator, that I have bought in 1988, I replaced the three cells back in 2001, and is still going strong. That was, indeed, an economic processor.

Maybe we can talk those guys at HP into "increase" a bit the efficiency to 220 or 230%, then you'll be able to use your pen-light cell to power two fans and a stove.

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SAK
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#5
In reply to #1

Re: General

10/13/2008 4:33 AM

I get your point i missed out on that .your UPS will probably work for 15 sec, only .

think you will need a 200 AH (12 V) battery as back up to last 7 hrs .

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bwire
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#6

Re: General

10/13/2008 5:17 PM

A 500 VA may power one 2core duo only but not a quad core.

You want a 1000 or 2200 VA UPS

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