That used to be our experience here (University Computing Service), but our current UPS has been supplying our machine room continuously for several years now and has carried it through countless minor (and a couple of major) power cuts.
On the other hand, our UPS is a big and expensive one, and I suspect that makes a difference.
In message , at
10:13:14 on Fri, 28 Jan 2011, Espen Koht remarked:No, it just means that after 18+ years of hype (the Apple Newton dates to 1993) and 10 years of significant advances in connectivity (the 3G auction was in 1990) we've finally got to the stage that there's a significant niche for PDAs with some web applications on them.
But what I need is a proper computer.
I also need a PDA, but currently even the biggest and best tablets still fall between two stools for me, so a smartphone that's almost now got the functionality I had in a 1991 HP95, plus a decent camera, saves me having to carry multiple small items around.
Oddly enough, it was an HP95 that I used at Vodafone's HQ in around 1993 to demonstrate a wireless connection (using one of their phones) to CompuServe, for genuine mobile email. They'd never seen that before, not even from their internal boffins. And, of course, being PC compatible, it wasn't that hard to port a suitable CompuServe compatible client to facilitate that, but I seem to recall it being a bit tight on RAM!
And people wonder why the network operators end up following rather than leading....
Hi Tone,
I've an old APC UPS which powers the server and desktop PC. The batteries don't last long as you say. It has to be overcharging, but I can't be bothered to delve into the unit to try and adjust the charging. I'm told the fire/burglar/water leak alarm industry changes batteries on a regular basis for this reason (and a regular maintenance contract income). I suggest every 2years might be sufficient. Maplin stock a good range of SLA batteries, not sure about the quality mind you.
Set the replacement date in your diary!
John
... and how good your local power company are at maintaining their equipment. We're about 8 miles out from civilisation, mostly with power fed via lines slung from poles at the side of the road, and seem to get just a couple of glitches a year - but then it's not uncommon to see maintenance crews out and about.
(although it still amazes me that it all works so well though, given that the temperature swing between seasons here can be as high as 70 Celsius)
cheers
Jules
True. I've actually got an unused well-shaft just behind the house with a shed on top, and the shaft walls are about a foot thick - that seems like a sensible spot :-)
cheers
Jules
In article , Jeff Strickland scribeth thus
I did mention that this wasn't a consideration as such, a UPS isn't to be regarded as a standby power system .. as it happens they only use a small amount thru it so if it lasts for around half and hour that will be fine...
In article , Espen H. Koht scribeth thus
That does now seem to be the case and in fact they have gone for the Eaton EX series so job done.
As regarding the ethernet connection totally agree. A Large Mge Ups we inherited has one of they, and very good and useful it is too:)..
In article , Roland Perry scribeth thus
Bin there, seen that, anguished over the lack of routine maintenance in the leccy industry;(...
Indeed hence the questions regarding APC. Seems from a few mails etc the Eaton / MGE ones are better in this respect..
Yes it is..
About the last place I'd buy batteries from, thats a distress purchase location;!...
What you call a significant niche is looking like it could go mainstream, which it will do without windows apps. It's not entirely unreasonable to argue it is the doomed efforts to create something usable based on Windows which have held things up, especially in the context of tablets, but you are correct that for an extended period good connectivity has also been a missing part of the puzzle.
What is your need for, exactly? A true UPS will supply clean power during *all* mains power supply problems, but will not be cheap.
The only reasons for using one are (a) to bridge a gap in supply or (b) to clean up a dirty supply. If all you want to do is bridge a gap, then a standby power system will be cheaper for the same capacity, as all it does is to take over from the mains when it fails, and is in standby mode, maintaining its battery charge, the rest of the time. They start operating within a couple of cycles of the mains going down, so most modern equipment won't notice the gap, but their frequency stability isn't always great, so something that needs a constant frequency will have problems.
A true UPS runs continously, taking dirty mains in and providing clean mains out, with a battery backup to cover power outages. It also regulates the output voltage within tight limits over a wide range of input voltages. The continuous running requirement makes the electronics much more expensive, which is reflected in the price. You'll need to check the MTBF with the manufacturer, too.
There is also a system for PCs to have an internal backup supply which will maintain the system for a specified time, though that's not what you've said is wanted.
Either way, the batteries will only last a couple of years, maybe three.
I visted a farm once, on the chalk hills above High Wycome. They had a well in the yard - 200' deep. Eek.
More like "EEEEEEEEEEEEeeeeeeeeeeeeeeeeeeeeeekkkkkkkkkkkkk!!!!!" Splash.
:o)
You have to do more research, but a UPS is intended for periods of seconds, perhaps a couple of minutes. It is for a short-term power outage that might happen due to switching circuits that reroute power due to lightening strikes on transformers. Basically, a UPS backs up the central power grid during momentary outages.
The operative term here is, momentary. If you measure the outage with a stopwatch, then a UPS is called for. If you measure the outage with an egg timer, then maybe a UPS will not fit the need.
That depends solely on how many batterys you choose to use, there's plenty of battery UPS solutions that will run for hours, even the small Eaton Rack units have the option of extra battery trays, I've seen a few that manage over a day in places where a generator's unwanted.
Often just long enough to save the file you're working on. Which is better than nothing.
You can buy leisure batteries for caravans that are better designed for deep cycle applications. Using a car battery in a caravan will kill it quickly, but the leisure batteries seem capable of taking quite a lot of abuse.
Regards
Stephen
The differences have aways been there between leiure batteries and starting batteries, though until about twenty years ago the only deep discharge batteries commonly available were traction batteries as used on milk floats. They are optimised for different discharge patterns. Even the deep discharge batteries won't take more than a few hundred full cycles, though if you keep to fifty percent cycles, they last four times as long. What mainly kills standby batteries are the long term chemical changes caused by badly controlled float chargers. Voltage is critical to within very close limits, and it must be temperature compensated. Not *that* hard, but it's the battery temperature that matters, and most units I've seen don't have remote sensors.
Yep.
IME, capacity drops linearly to zero at 4 years max, but it's no use waiting until they are zero, as you've had no effective UPS cover for some time. You need to take this drop in capacity into account when sizing and considering the battery replacement regime.
I've kept several cars for 8 - 11 years, and never had an original manufacturer battery fail in that period.
Difference in a UPS is they are charged very quickly so the UPS is ready for another outage as fast as possible. The higher voltage required to do this kills them. ISTM it would be easy to overcome this by falling back to standby voltage level when charged, but UPS's don't seem to do this, and it would reduce the manufacturers' revenue stream from the after-sales consumables.
There certainly are giant commercial datacentre UPS's (the sort with a battery room), and things like phone exchanges, where the batteries can last decades, but I presume the charging circuits for these are designed for long battery life, because replacement of these battery sets costs a fortune. (I worked in one place with a 100kW UPS where the batteries must have been 10+ years old, and were subject to an annual maintence check.) We actually had the UPS fail and need replacing, whilst retaining all the original batteries.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.