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Nate Nagel Nate Nagel is offline
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Default Uninterruptible Power Supply question

wrote:
On Feb 26, 4:19�pm, "N8N" wrote:

On Feb 26, 11:47 am, Bennett Price
wrote:






Art Todesco wrote:

mm wrote:

On Mon, 26 Feb 2007 02:57:59 GMT, wrote:


I know this isn't exactly OT for this group, but I couldn'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


What bob siaid. �But while I'm here, every such thing I know should
work somewwhat or maybe well without batteries if you have AC. �I
don'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.


batteries to be flat, but the light for the incoming wall power
doesn'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'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't worth
the bother? And just how do I get rid of these, if they are junk?


aem sends....

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


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


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- Hide quoted text -

- Show quoted text -



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


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'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't believe the markup. If you have a
friend that works in fire alarm, security, etc. it's definitely cost
effective to replace the battery in a still-good UPS.


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


I'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're discussing is that you can reliably pull the same number of amps
as the battery'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

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