old computer battery backup for inverter

[(unknown)]

I was at a discount/junk electronic store today and was looking at the old battery backup systems they had. There were sizes from a single outlet to industrial network backup. I was wondering if the inverter electronics could be used to power home thing (lights, tv , radio, fans) if I was to take it a part and hook it to my battery back instead of the small battery that is in the original unit. Does anyone think this will work? These things are cheap and have High watt ratings ( 3500watt on some of the big ones and 1000watt on the smaller ones).

Editors note;

A search for "UPS" would kick up a herd of stories on just this subject. But since so many of our users are so patient, I left this so we can cover it again for the 476th time.

[dinges]

Editor is right; I posted this story yesterday:

http://www.fieldlines.com/story/2006/5/18/21734/4087

[Phil Timmons]

"Editors note;

A search for "UPS" would kick up a herd of stories on just this subject. But since so many of our users are so patient, I left this so we can cover it again for the 476th time. "

Well . . .  sort of.

The actual Scops search feature sucks bad.

Not that I am bytching, this site is free access.

ups gives everything from "ups"tate New York to "ups"stairs.

"ups" gives nothing.

"UPS" gives one single thread from 2 years ago.

The google search works better, but gives many mutliple references to the same thread.

Not that I am bytching, this site is free access.

The FAQ's seemed like a heroic attempt to stop the re-re-repeat questions, I guess, but they are from 2003?  And did not get so far as UPS's?

Not that I am bytching, this site is free access.

You have my sympathy. Drive on.

[dinges]

Huh?

Just did a search for '[space]ups[space]'. Look what the cat coughed up:

http://www.fieldlines.com/?op=search&offset=0&old_count=30&type=story&section=&s
tring=+ups+&search=Search&count=30

[dinges]

95 hits, in fact.

With plenty on the exact topic of the original poster; e.g. nr. 15.

I'm definitely not bitching about this board...

Peter.

[asheets]

One topic that hasn't been covered about UPS/inverted conversions is price.  I did post once about that, but we didn't come up with any good $$$ figures or guidelines (other than free=good, of course).

My story is that I picked up 2 SOHO units (marked "dead") at the University of Colorado property disposal auction for $10.  One worked just fine, and the other just needed its battery hooked up.  So, I never got around to trying a conversion.  But, I do know that if you do try it, you'll want to disconnect that stupid buzzer.

[asheets]

Oh, and another hint I have (this one coming from actual operations of a SOHO UPS in a corporate environment).

Pay CLOSE attention to the amp-hour ratings.  A typical SOHO unit will run a computer for about 20 minutes, but it won't run long enough to power both a CRT monitor and a computer to shut the computer down cleanly (about 15 seconds).  So, don't even think about running a TV with one of those things...

[TomW]

Alan;

One topic that hasn't been covered about UPS/inverted conversions is price.



Another, very important consideration for RE use is the horrible efficiency of the several I have tried.

One 48 volt unit I tried used about 10 amps just powered up. Any loads were added to that.

I just found it unacceptable beyond "desert island" stuff.

Cheers.

TomW

[dinges]

I checked my UPS yesterday during operation in the blackout. Driving a 7W CFL (220V), it needed .5A @24V = 12W input. Not too bad, IMO. It could also drive the TV, without problems. The price was good too (free). I've added external connectors so I can hook up external batteries to it (2x12V/12Ah), and intend to wire several batteries like that in parallel for greater capacity.

Admittedly, it's not the ideal solution for complete off-grid living, but for the moment it's a very good solution (for me).

10A just for the UPS? Wow...

I still have to take care of that annoying beep, though after about one hour I hardly noticed it anymore

It comes in a nice, small package; portable; starts up under load, without external 220V present (no need for special, magic key-sequences to make it live).

All in all, I'm quite happy with it. But, if anyone cares to donate a (defect?) inverter of 24/48V @ 3000W, I won't complain either...

Peter.

[asheets]

10A at 48V?  Holy %^&%*& cr@p, Batman!

This is why I build my own...

[dinges]

Thought that too; until I realized that maybe, when fully operational, this thing would draw 100A @48V (i.e., be a 5kW unit, using 500W stdby). 500W is still a lot of power, but if the beast can supply enough watts (that you actually need and have the batteries for), who complains. Like most things, UPSs/inverters exist in many sizes.

Either that, or maybe something was really defect in that unit?

[Phil Timmons]

[Phil skuffs foot on ground]

Well, ok that [space] part does make a difference.

Actually thanks for pointing that detail out.

Hey, speaking to other parts of this thread -- I am picking 4 junked (probably just dead batteries) UPS's tomorrow.  Dunno their size (VA), yet.  Got them just for RE hacking if anyone really feels the need.  Picking them from the local FreeCycle group (rEcycleDFW@yahoogroups.com) -- if anyone feels the need to play with some.

[commanda]

The other thing to watch for in used inverters is the battery voltage. Generally, the more powerful they are, the higher the battery voltage. I've seen them anywhere from 12 to 72 volts.

The other point to watch, is they generally use SLA, not flooded cell batteries. The two different technologies use different float voltages. If you rip out the SLA's and use external flooded cell's, you'll have to do an occassional boost/equalize charge to keep them in condition (assuming you use the UPS plugged into the mains to float charge them).

Amanda

[nothing to lose]

Yes alot posted on this already I agree. I have posted a few things too. And read many others.

I am running a 48V Matrix 5000 right now. Currantly it is on grid as a half house backup. I have tested it well as an inverter with about a 120amp  48V battery bank and not grid connection. Ran the airconditionare nicely for awhile. I did not test the power usage since I won't care about that later. I plan to mostly turn it on, run the 220V well to fill a large tank, shut it off again. Then use 12V or 120v pump from the tank to the house for 24/7 water as needed.

I have used many 24V input sinewave UPS's for various inverter use. Just wire up a large battery bank and ready to go basicaly.

How efficeint they are may vary, rather as good as a true inverter only maybe not, $5 for a sinewave inverter still the best deal around!

I had 4 $5 each as dead for parts that worked perfect with good batteries. I think 3 were 1,000 watts and the other maybe 900watts?

Rather they should be used as is with a larger battery bank or try to mod them in various ways is up to the user and their abilities. They work fine normally as is, just don't plug them in.

All of mine so far have cold/hard started directly off the batteries without the grid, I have read some won't. Most have a way to shut off the beeper without modding or destroying anything, some don't.

I played with old Modwave UPS's also and had same good results.

I noticed with a Sinewave UPS that when it was hard started off batteries only that one ran a fan slower than normal like a modwave inverter would do but when I connected the grid the fan sped up to full speed. When I unplugged the grid though the fan stayed running full speed. So that one seemed to be working as a modwave and needed the grid to kick it into sinewave mode? Probably not exactly correct but the way it seemed anyway.

Mostly APC is the brand I been messing with, because they are the most popular so easiest to find older models with dead batteries.