need to build a UPS for computer

[charmer]

Hello Friends,!

I am looking forward to provide my cpu + monitor a 1hour backup when there is no electricity. As soon the power fails the UPS relay should be able to pick up the load thus not keeping the system running smoothly. When the power comes back the UPS should be able to shift back automatically.

I would like to do this for my project and should be easily done in home with less expensive tools.

I think what i would be needing is,
1000W rated inverter
Car battries

But how to make them work with the cpu?

Please comment/suggest

Thanks alot.

 

[blueroomelectronics]

Pie in the sky.
You're dreaming, it'll cost you more than buying one.

 

[Kryten]

why dont you just google??

Here is a couple of links:
http://www.dansdata.com/diyups.htm
http://www.edn.com/contents/images/41102di.pdf (for USB device but anyways)
**broken link removed** (looks to be the best)

 

[Papabravo]

Hello Friends,!

I am looking forward to provide my cpu + monitor a 1hour backup when there is no electricity. As soon the power fails the UPS relay should be able to pick up the load thus not keeping the system running smoothly. When the power comes back the UPS should be able to shift back automatically.

I would like to do this for my project and should be easily done in home with less expensive tools.

I think what i would be needing is,
1000W rated inverter
Car battries

But how to make them work with the cpu?

Please comment/suggest

Thanks alot.

A bouncing relay would never be fast enough.
Buy one - you cant make it as cheap

 

[rjvh]

same advice as the others buy one

what you can do is buy a lighter model and change the batery pack your self

if it is only your computer (if you have a lcd screen) a small 650W inverter would do it already for a long time you increase the baterry size your self and you have your extra time

Robert-Jan

 

[I²R]

Building a UPS from the ground up is like making a copy of Romeo and Juliet by buying magazines and cutting out the words aned pasting them to blank pages: you can do it, but it'll take a long time and you'll wind up paying way more than if you just bought it.

 

[blueroomelectronics]

Building a UPS from the ground up is like making a copy of Romeo and Juliet by buying magazines and cutting out the words aned pasting them to blank pages: you can do it, but it'll take a long time and you'll wind up paying way more than if you just bought it.

Tell that to the members at Electronics Lab

 

[audioguru]

I am also a member of Electronics-Lab.
I helped fix an old inverter design there that didn't work. It uses old 2N3055 transistors because Mosfets are not available in the 3rd world nor in the 4th and 5th worlds.

I can buy a pretty good and cheap inverter that was made there. Those people can't buy it.

 

[blueroomelectronics]

Audioguru you ARE electronics-lab, if you didn't post the forums ther would be an electronic wastebasket.

The let wise old man be a moderator and he's like 8yrs old, maybe they'd let you moderate.

Can't see why eplanet isn't a moderator?

 

[Hero999]

Audioguru use to be a moderator overthere but I believe he quit after an argument with the nasty moderator who got the administrator on his side.

 

[audioguru]

The nasty moderator over there has deleted many of my posts.
He is very quiet lately, maybe he will vanish.

The 8 years old Wise Old Man has given me hundreds of PMs all with horrible spelling.

 

[blueroomelectronics]

I delete PMs from people wanting me to do their homework for them. If a PM looks like it was OCRed from a crayon written note by an 8 yr old it goes in the bin.

Anything with more than 3 periods in a row, the bin.

What forum does he moderate?

 

[charmer]

battery and inverter?

wont battery and inverter makeup a good ups?
i only need it to provide non stop power in case power failures.

 

[charmer]

battery and inverter?

wont battery and inverter makeup a good ups?
i only need it to provide non stop power in case power failures.

 

[I²R]

Well, that's what a UPS is. You also need a charger for the battery. Even at bare minimum, I can't see you putting one together for less than the cost of a commercially-produced unit. I just bought a brand new APC 1300 kVA UPS for about $150

 

[rjvh]

Well, that's what a UPS is. I just bought a brand new APC 1300 kVA UPS for about $150

tested and guaranteed, why making one???

 

[blueroomelectronics]

The mains power in Karachi is very unreliable the power companies turn it off because of late bill payments or outright theft, a UPS is designed for rare power failures and will draw more power as it recharges between losses. Why not buy a generator instead?
https://www.dailytimes.com.pk/default.asp?page=2008%5C03%5C07%5Cstory_7-3-2008_pg5_7
https://news.bbc.co.uk/1/hi/world/south_asia/7280933.stm

 

[hackableFM]

I agree with the comments above, It will be cheaper by far to buy one than make one!

If you insist on making one then the easiest way would be to buy your inverter and run it on battery constantly, but build a charger for the batteries which can supply more current than the inverter can use. This type of UPS has absolutely no dropout what switching over to battery.

I think they call this an 'Online' UPS. If you build an inverter that switches over to battery when the mains fails then they call these 'Offline' UPS's.

I personally have a UPS pretecting my machine but I was VERY lucky in that I picked it up from a local junk stall for £1. Yes you see correctly £1.00 Fair enough this one needed a new set of batteries but they only cost £20. Maybe you should keep looking around on junk stalls, You never know what you might pick up!

hackableFM.

 

[HS3]

My desktop and CRT, although they are rated much higher, actually only consume somewhat less than 200W. I have a 500 W UPS which came with a tiny 7AH battery which was just enough time to save your work when the power failed. When that battery failed, instead of replacing it with a similar one I got an old car battery. A battery which is unable to crank a car, specially a diesel, will still have plenty of life in it, has much more capacity than 7 Ah and it is FREE! Still, I do not expect to be able to work for hours, only that it may solve short blackouts or give me time to save my work.

If you want to maximize time off grid at the lowest price I would (1) get a laptop with a 12 V adapter and (2) install a bank of old car batteries. You can't beat that combination.

 

[HS3]

A bouncing relay would never be fast enough.

My Ellipse 500 has a relay as do many others. The charge in the computer's PSU capacitors is enough to carry through the time it takes the relay to switch and the inverter to start up.

By the way, I also used to post at that other board but I left in disgust.