Hi... The other (little known) "Feature" of some of the later UPS's, is that once fully charged, and if shut down the right way, you can often power them up "Off Line" as a portable source of AC power if you so need. On a light load, they run for quite a long time! OK, so the run time can be short if heavily loaded, and you often have to tolerate the nagging beeper, but the facility is there on many of them.
For others, the dodge used to be, pull the incoming AC lead, and after they have taken on the load, shut them down from the front panel. Then they will usually let you power up things again if needed, with the incoming AC line still missing!. Sadly, if you try to use higher capacity batteries, that is, "many times" higher (cabling in say 80AH batteries instead of the original 17AH types!) their internal chargers can't cope, and flag the batteries as bad all the time, even if they are the same "type" (AGM, Jelly etc) as the originals. (Some of the small desktop units, have pitiful chargers, literally just a trickle at best...) Also with second hand UPS's, as many of them are fan cooled when running Off Battery, and there is often little to no air filtering, remove the cover (after all the usual precautions) from time to time and blow out all the dust bunnies and dead bugs etc, & also check the fan is OK. I currently have one APC1400 device running things at home, cheap via eBlag with sick batteries (replaced of course) and I also have an eye on a rack mount 1kW unit here at the office, that is currently complaining of bad batteries. It's not the newest, and we've changed the batteries several times in the past, but the IT peeps will probably just want to swap it for a new one now, as they do. Problem is, that'll probably happen next week, when I'm not here. Expressing an interest now could cost me. Waiting for it to gather dust after it's redundant, then offering to "dispose" of it for free, costs less. :-) The nice (if that's the right thing to say) thing about the APC range, is that the built in native UPS support code in Windows (certainly in Win2k) was developed with the help of, or by APC, and has options to run other programs just before things are finally shut down. That is mainly meant for notification etc, but can be good for a host of things, such as remote shutdown of "other devices" also living off the same UPS... The not so nice thing, is the custom cable needed for the older serial port equipped "SmartUPS" devices. The lead details are on the web if you search. If not just ask, I'm sure I have it on record somewhere... As for reliability. One we have here on a print server, an old SmartUPS 400, on it's "nth" set of batteries, and is coming up for it's 20th birthday soon! It just keeps on going. We only ever had one permanent hardware failure in the past, and I suspect that had something to do with the big dent in the side of the case it acquired at the time! Despite all the warnings, the batteries are usually generic types and easily sourcable, just not with the "approved" logo, and pre-wired as a ready to go pack. The secret is to identify the originals before you throw them of course, then get like for like (characterised for Float, or Cyclic use accordingly) just that often nowadays, for the same physical size, you get a few extra A/H for your money. (Google is your friend in this respect!) Also, keep your UPS cool. Heat kills batteries. Lastly, as in most UPS's (except the small desktop units) there are often more than one battery in the set, often a pair, sometimes 3 or 4 (or more in the very big units.) Try and identify the "bad" one, then keep the others for other needs. Solar charged lights in an outhouse, etc. They can often have quite a lot of life left in them, for such retirement uses. Don't try to replace just one of a set in a UPS, you'll only have trouble!... The only exception of course, is in the case of a genuine "Must do" emergency.. Regards to All. Dave B. > -----Original Message----- > Message: 3 > Date: Mon, 10 Aug 2009 09:21:09 +0200 > From: Magnus Danielson <mag...@rubidium.dyndns.org> > Subject: Re: [time-nuts] Power Back-up > To: Discussion of precise time and frequency measurement > <time-nuts@febo.com> > Message-ID: <4a7fca65.5010...@rubidium.dyndns.org> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Joseph Gray wrote: > > Over the years, I have gotten several APC Smart UPS for next to > > nothing. In every case, all they needed were new batteries. Unless > > they are physically damaged or a circuit board is toasted, they seem > > to work fine. The attitude seems to be "The battery died, throw out > > the UPS and buy a new one." > > That's how I got UPSes. The first once caused me much trouble, until > I've learned that it needs working batteries to even power up > properly, > since the relay that breaks the line in needs power from the > battery to > engage... dead batteries => dead UPS. That relay is needed in > order for > the invertable AC/DC converter to not try to feed the devices on the > feed-side of the UPS on power failure, so it is not illogical, just a > feature of the design. > > Getting new batteries for the UPS have solved my problems since I > learned that lesson. Have another big one which needs new batteries > awaiting my attention. > > Cheers, > Magnus _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.