Best use for 50 small UPSs?

[Laylow]

I may be able to get 50 APC 280 UPSs with batteries in varying states.  They say that they have a max output of 180 watts.

What would be the best use for these or are they even worth messing with?  Is there any way to use them together?  What would one go for without the battery?

Thanks

[willib]

they dont have the batteries?

you could use them seperatly , like have one per electrical socket , if you dont exceed the rating ..

and use your battery/batteries for the 12 or 24 volt input..

[Laylow]

They have batteries but I don't know if they are good anymore.  I imagine that most of them still have some life in them with a few bad ones in the mix.  A few of them may be brand new.

[Nothing40]

I've had some success with "desulfator" circuits on SLA's.

It's worth a try,might get a few batteries back to a usable state.

I've also had fairly good luck reviving SLA's by popping the vents open and adding some water to the cells,and giving them a trickle charge for a day or two..

Some people say it's a bad idea to add water,but it seems to work fairly well for me?

Just do it in gradual steps,don't add too much! It will spill out of the top.

I usually use a big plastic syringe to squirt the water down in there,and measure it out.

Some UPS's are picky,and won't turn on without 'grid' power..Sometimes there are ways to trick them,using the various buttons,etc. A Google search for that model might pop up something.

On my 400W UPS there's a 9-pin D-sub connector on the back,theres a pin on there that will force the UPS on/off if you pulse it to +V/GND.I just used a couple pushbuttons on a piece of perfboard. ON and OFF.The manual should have the info,if you can find one.

I ran some havy wire out of the case,with big ring terminals on the ends to connect to a 24V battery bank.A quick test with a couple car batteries showed the runtime meter maxxed out at 99:00 minutes,while running my PC+CRT monitor for about 30 minutes,it just stayed there.

[drdongle]

A new APC ES 350 ( 200 W) runs about $40 and replacement batteries will cost $10-$15

So you need to get them REALLL cheep.

[ghurd]

They are often free for the taking.

[dinges]

Ghurd,

Theft is not an option ;-)

Seriously though. Where do you suggest to look at? I recently got an old (but fully functional, after replacing batteries) UPS, 800W/1400VA. I have rewired it to use external 24V too. It was being outphased in my brother's company, and he thought of me. Word of mouth is good, but if there are places that are chucking them away by the dozens, I'd like to know...

Peter,

The Netherlands.

[ghurd]

Hi Peter,

Check the local ISPs, if there are still any over there (not many left here).  2 blocks / 400 meters from here, the ISP does maintaince for UPS's too.  Last time I was there they had 20-ish from a couple retail stores.  WHY??? They didn't fit in the dumpster!!!  It was cheaper to replace the entire unit with a new unit, than to change the battery.  "The Guy" was not sure, but "something about new cash registers, more power, new batteries, or something..."

About a year ago I bought a 350VA unit clearanced priced at Wally-World for US$8 just to get the battery in it.  Cheaper than shipping costs for the SLA battery.

Look for whoever changes the batteries or UPSs or cash registers.  It is all junk to them.

About the 20-ish UPS units. I wish I knew better at the time.  They didn't have any since.  I think because they are one of the last small ISPs.

G-

[Bruce S]

Laylow;

   These type of UPS's are pretty good, the ones that just flat don't come on even plugged into the wall means that the board on the top has been shorted out and the unit is only good for spare parts.

However if you get units that do come on, then one thing you could do is plug it into an AC and let it set "ON" for about 30 mins; then check the battery. It should read way up close to 13Vdc out of circuit. This will means the battery is still good.

Anything else and it's toast.

The reason for this is that APC's smaller UPS's are really bad about constantly over charging the battery and over less than 6 months (which BTW is just long enough to have the battery out of warranty). This happens to some of the older 1400 and 3000w units as well and unless you are dilligent about up-time load testing you won't find out until you really need the unit to work. With this in mind, you could also take the batteries out of the units one at a time and shake them listening for "rattles", if you hear ANY, the battery is toast.

Usually for a small fee, you can take the batteries in question to places like batteries plus and ask them to do what is called a "Lifecycle" on the SLAs this will take a few hours to test, but it is the end all of tests. Not only will it tell you if the battery is any good , but also tell you how much of the original load size is left and will also try to regain some back by "cycling" the batteries. The old small NiCds that I've sent to a few here on the board, go through this very test wit the very same type of tester that these places have.

If you get them for free take all of them, if they cost try offering now more than $3 - $5 /ea of even say $50 for the lot. As you really don't know what shape the batteries are in.

BTW: I have a smaller 200VA and it's what I run my freezer off and it's doing just fine.

As some one else said if you can get the schematics...good. There is a way to bypass the "look for AC first" logic and will be able to use these without plugging into the mains, but you'll also want to find the logic for the beeper as will will be on too.

Hope this helps some

Bruce S

[Dreadstar]

Good points. Main reason i stopped buying APC ups. they love to turn good batts into swelled ones. have had to take apart many of them to get the toasted ones out. Can you say Overcharging? and the sine wave output on most of them is closer to a square or saw tooth than true sine.