Uninterruptible Power Supply question

[<aemeijers]

I know this isn&#39;t exactly OT for this group, but I couldn&#39;t find anything in the comp.* tree that looked right.

I have 2 MGE UPS systems Pulsar 14+, that have been sitting around unused for a year. (Long story about life getting in the way...) When last used, they lit up and took a charge fine. I pulled them out today, now that I finally cleaned out and rearranged my computer work area, and wanted to put them back in service. Nada- no lights, no noise, no nothing. I expected the batteries to be flat, but the light for the incoming wall power doesn&#39;t even come on.

Anybody out there (Jeff W.?) have any idea what is going on? These are from a garage sale, so no docs. I looked on vendor web page, but didn&#39;t find anything about dying in storage. Did the batteries (gel packs, like a fire escape light?) crap out completely? They were never dropped, never frozen, etc. Any point in trying to repair or replace the battery packs? Or are new ones so cheap it isn&#39;t worth the bother? And just how do I get rid of these, if they are junk?

aem sends....

[Bob]

Go to sci.electronics.repair and search for UPS. If you can&#39;t find your answer, ask them. Bob

[mm]

What bob siaid. But while I&#39;m here, every such thing I know should work somewwhat or maybe well without batteries if you have AC. I don&#39;t think this will help, but disconnect the batteries altogether and see if all but one light lights. If not, start iwth the basics, the cord, the switch, looking for damage on the circuit board.

Maybe check the lights too. Maybe they share a common ground that is bad.

And check the output. Maybe you do have 110 coming out of it.

[Art Todesco]

Just an add, some UPSs completely shut done with bad or no batteries. The one right in front of me does that. I don&#39;t remember if the power lights worked or not with bad batteries, but I know the computer did not get any power.

[Bennett Price]

And to add to the above, if the batteries were sitting around for a year w/o charge, (and were old to begin with), they are probably completely dead. If they are 12 volts, you could take your car battery out and temporarily hook it up to the UPS to see if it would work. Or string together a bunch of flashlight batteries, preferably rechargeable.

[Art Todesco]

And to add to the add, many UPSs use 2

12 volt batteries in series, so you might need 24 volts.

[Malcolm Hoar]

That is indeed possible if not likely.

Please do NOT try this unless you really know what you&#39;re doing. And if you really knew what you were doing, you&#39;d know enough not to do this.

[Malcolm Hoar]

I wouldn&#39;t do either (and I&#39;m an EE by training).

But especially don&#39;t mess with the car battery.

1. A car battery contains a LOT of stored energy. Those really thick cables attached to your car battery are thick for a reason.
2. It&#39;s easy to release that energy very rapidly (e.g. with a short).
3. The probabily of an accidental short is HUGELY increased with quick and dirty temporary wiring.
4. In the event of a short, the resulting explosion can cause concentrated acid to be sprayed all over the area as well as globs of molten copper and more. Trust me, you don&#39;t want to be near by.

It&#39;s about as dangerous as fooling around with a chain saw except that the dangers are a lot less obvious to a casual observer.

Don&#39;t connect large capacity batteries (esp. lead acid) using anything except properly rated cables and connectors/ terminations.

In the case of a UPS, the said applicance is simultaneously connected to the utility power creating even more scope for accidents. A broken UPS is by definition umm, broken, increasing the risks still further since it may do things that are unpredicable and out-of-spec.

[N8N]

Easier and probably safer would be to simply buy a replacement battery. If you have an ADI or similar store nearby, the batteries used by a UPS are the same as the batteries used for emergency lights, fire alarm panels, etc. - just match chemistry (likely sealed lead- acid) voltage and amp-hour rating. take the old one(s) with you. I am currently using a really old APC UPS to back up my cable modem (I use a laptop) that I scavenged out of a junk pile; the only thing really wrong with it was a dead battery which I matched up exactly to a fire alarm battery which is in it to this day.

nate

[hallerb]

New batteries cost nearly as much as a brand new comperable sized UPS.

IF one decides to use a car battery at least install a fuse, small amperage to protect things if you screw up.

[<aemeijers]

(Long thread of helpful hints snipped)

Thanks, guys. Don&#39;t worry, I realize I&#39;m not an EE (though I do have access to one), so no dangerous acid-based homebrew kludges. I am 99% certain there is no mechanical faults in the circuits, since the units worked when stored away, and the odds of the same fault in 2 units not in use is slim to none.

My first thought was that the sealed batteries crapped out, and several of you seem to support that. No time this month, but when I get a slow day, I&#39;ll open the units up, using the instructions from vendor website, and see if any of the supply houses in town have drop-in replacements for less than half what it would cost to get new UPS units from Sam&#39;s Club or mail order.

Based on prior experience in my day and side jobs, I predict these are &#39;not economical to repair, based on expected remaining lifespan&#39;. So one question remains- how do I legally get rid of old ones? &#39;Free&#39; pile in spring garage sale? Keep watching ad paper for county HazMat day?

aem sends....

[Malcolm Hoar]

I replaced the battery on my APC UPS. I don&#39;t recall the exact costs but it was certainly economical. APC sent me the new battery and a prepaid shipping label to return the old one (for which they offered a credit I think).

As for disposal... it almost certainly depends on your location. Around here (San Francisco Bay Area) car batteries can be dropped off at various locations. Last time I needed to do that, Kragen Auto Parts accepted them for recycling. I suspect they will take units from a UPS too.

Otherwise, call your local garbage company, city or county offices. In my experience, they&#39;ll quickly tell you how to correctly dispose of just about anything. Actually, I sometimes think that&#39;s the only thing they&#39;re any good at -- they&#39;ve never been much help to me with anything else ;-)

[Nate Nagel]

Depends on who you are and who you know. I was an engineer for a branch office of a major fire alarm supplier at the time; I can&#39;t remember if I got the battery I needed "at cost" or the warehouse guy just told me to take it and get out of his face. (probably would have cost the company more in his time to do the paperwork to charge me for it than it would have been worth, truth be told.) The distributor cost on those things is ridiculously low; you wouldn&#39;t believe the markup. If you have a friend that works in fire alarm, security, etc. it&#39;s definitely cost effective to replace the battery in a still-good UPS.

I&#39;ll agree with that; I think a typical UPS battery is something like

10-12AH; a typical car battery is something like 60AH. This is handwavy, but a general guideline for a lead-acid battery of the type we&#39;re discussing is that you can reliably pull the same number of amps as the battery&#39;s AH rating without serious voltage drop due to battery internal resistance; obviously short circuit current will also be a rough function of capacity if that holds true. Bigger battery = bigger spark = bigger boom (if things go pear-shaped.)

nate

[mm]

Measure the voltage on the current ones before buying new. Even on the UPSes that don&#39;t work without batteries there must be a lower voltage limit for them not to work.

Baltimore County has four places, one of which takes batteries. In addition the junk yard I go to most often takes batteries, maight even pay a bit for them (I didn&#39;t ask) and I would think most junk yards reccyle car batteries as well as these.

But I don&#39;t believe at the right store the price of baytteries is alsway close to the price of a USP. Prices vary widely on the net, for example.\\

The size is in the url. None of this is more than 20 including shipping. I havent&#39; dealt with him but the vendor has 2400 sales and a 100% positive rating, over 4 years Except one of the four doesn&#39;t give shipping costs. Shipping is half for items after the first one..

[dreamchaser]

Agree with measuring the voltage first. Heck, the voltage is going to be low. Why not just determine what the battery voltage is supposed to be and if it&#39;s 12 volts, put each battery on a car battery charger for a few days. Check the voltage, did it go to 12 or more? If so, put them in and see if the ups will come up.

I&#39;m only familiar with commercial large scale UPS&#39;s, know nothing about these little guys. What happens with these little UPS systems when the battery voltage gets low after a power outage? Do they just shut off, switch to raw power or what? Your system may just be experiencing what it thinks is a low battery condition and it does make sense that the circuitry would be such that if there was no battery voltage, the unit isn&#39;t going to do anything but shutdown. It also may require some battery voltage to even turn on.

Consider the car battery charger idea just to see if the batteries will take a charge then try them.

The stored energy in a car battery is much greater then the 60ah mentioned, go by cold cranking amps and your are looking at 500 plus amps of power instantaneous. If you are the adventurous type, put the daggone ups in the driveway, run a couple number 10 gauge wires to the ups, run a 100 foot power cord to the ups leaving it unplugged from the house or garage, plug it into the UPS, and then go back and plug it into the garage or house. Get your binoculars and try to see if any lights are on on the UPS. Also maybe consider waiting until night time to do this just to get the benefit of any short circuit there is, or July 4th. Sorry, just having a little fun but not serious, best to play it safe.

[mm]

Thanks for the detailed answer. I see what you mean.

[Deke]

I bought a new 900 ups and it would not stay on when I first applied power. I figured the batteries were drawing too much juice and shutting down the whole system.

I hooked it (the battery) up to my automobile battery charger and gave the battery a quick charge and it has been going fine for 3 months.

My point is that the UPS may need a little help getting the batteries to a satisfactory state so it can start charging them.

All 3 of my UPS charges uses a 12 volt lead cell. On two of them, I have connected up sears die hard batteries and thrown away the little batteries it shipped with. When power goes with ice storms or hurricanes, I can keep computing for up to 12 hours.