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UPS

Community Veteran
Posts: 1,236
Registered: 02-08-2007

UPS

I am wanting to add aUPS to my network. My network is detailed here:
http://www.seanbranagh.com/network
I have all the equiptment in my house wired to one main cable so I can isolate it all at the same time. For this reason I would like a UPS capable of powering everything so I bought this toy from Maplin: http://www.maplin.co.uk/Module.aspx?TabID=1&ModuleNo=38343&doy=7m8
It appears to be very accurate as I tested it on various appliances which had a power rating on them such as kettles and light bulbs.
I was happy to find that 3 computers, 2 TFT monitors, 1 laptop, 2 access points, 1 router, 1 switch, 1 cordless phone and my Roland electric drum kit came to a total of only 480Watts approx.
This means that the Trust 950VA UPS from Maplin would do the job for everything: http://www.maplin.co.uk/Module.aspx?TabID=1&ModuleNo=44811&doy=7m8
Problem is that it would not run for very long with this load. My question is, Would I be able to connect another lead acid battery in paralell to the internal one to increase the running time? I was thinking of something big like a 80Ah leisure battery or maybe even a car battery. Would the UPS be capable of charging this? Personally I cannot see any reason why not but I would like a second opinion. Thanks, Sean.
27 REPLIES
Community Veteran
Posts: 1,574
Thanks: 3
Registered: 13-04-2007

Re: UPS

In theory it should charge any suitable battery the question is how much charge can it put out?
If one battery took 1 day to charge its possible 2 would take to days as it may not be able to put out any more charge.
The time it can run all the equipment may not vastly increase.
There is only one true answer suck it and see.
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: UPS

Doesn't really matter how long it takes to charge. As for the running time there should be a vast difference as I would be upping the capacity from about 12Ah to about 80Ah!
Community Veteran
Posts: 14,469
Registered: 30-07-2007

Re: UPS

You should not use a car battery as it is not designed for the type of charging that UPSs use. They are also designed to supply a very high current so could damage the UPS. You should only use batteries designed for use in a UPS, which you can get from Maplin and other component stores.
UPSs are really designed to keep the basic units running in the even of a power fail to reduce the likelihood of damage should the power be lost immediately, so should not be used to power monitors / printers or other items other than the base units. That way you will get the best running time on batteries.
You also have to look at how you shut all the equipment down properly when the battery runs out. Fitting a UPS without the means to do a tidy shutdown often defeats the main object of having one in the first place.
Finally, while the whole lot may only use 480W in normal running, many items have a higher current draw when running like CPU, graphics card etcl. So even a 950VA UPS may struggle when on batteries.
Community Veteran
Posts: 14,345
Thanks: 685
Fixes: 10
Registered: 01-08-2007

Re: UPS

To be honest, I don't think running all your network from one power point is a good idea. I run each PC on my network from different power points (Ok, scanners, printers etc are all plugged into that PC's 5 way socket extension but there is one of those for each PC).
My advice would be to simply use the UPS on your main server in the attic. That will allow it time to stay online longer and then finally perform a safe shutdown. For the other PC's, have a 2nd UPS which can supply them for a limited time in order for them to shut down safely.
At least that way your main server stays alive (along with swtiches etc) but your other PC's won't hog the power it depends on. You can then log into your main server via vnc/RD and still get basic access to your network from outside during a power failure.
Personally when I can afford to I'm intending to build a mini-itx based XP gateway, with one gigabit switch and backup UPS with a heavy duty machine available via wake on lan if needed. That will keep it online 24/7. My other PCs won't matter quite as much. Monitors, printers etc will definately not be using a UPS as it would be a large power drain for CRT monitors. If I need to do anything, the laptop (being battery powered) will suffice for a display using RD or VNC.
I need a new signature... i'm bored of the old one!
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: UPS

Quote from: okrzynska
To be honest, I don't think running all your network from one power point is a good idea.

If you look at the picture and closely at my post you will ssee that it is not one power point but one 30amp cable I have wired directly into my socket ring complete with 6amp trip and 2 seperate 3 amp fuses. I bought the UPS today and as I am posting this the UPS is sitting in front of me with the top off connected to a 17Ah jump starter battery plus its own battery and happily powering my entire network. Based on this test I am going to ignore all of your advice and hardwire it in with a car or leisure battery, sorry. LoL. I noticed in one of the posts about a car battery and the large current it can deliver. The current flowing in a circuit is not determined by the power source but by the resistance of the load and would be no different than that delivered by the UPS own battery based on the fact that a car battery and a UPS battery are both lead acid and will have a voltage of about 13.5. Same will apply to charging and discharging the battery through the UPS. Only diference is that the car battery will take much longer to charge and discharge therefor longer running time.
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: UPS

I do not plan to run my desktop machine on the UPS. If I am not at home this machine and its 2 TFT monitors will be off anyway. If I am at home the machine would be shut down straight away and I would switch to the laptop as it (with the monitors) accounted for almost half the calculated power consumption. The only reason it is going to be connected to the UPS is because, like I mentioned earlier, everything is already connected to one place which makes it easy for me to hardwire the UPS to.
Community Veteran
Posts: 14,345
Thanks: 685
Fixes: 10
Registered: 01-08-2007

Re: UPS

Hi Sean
Yea sorry mate I didn't notice you'd got it hard wired into the ring! Having just read what you've written it's a impressive setup you have but even so I personally wouldn't rely on just one power point (EG fuse in the fusebox going would leave the entire network stumped).
I never commented about the car battery - That was the other guys!
Be sure to let us all know how you get on with the UPS! It would be interesting to know how long it lasts when you test it etc.
Oh, btw, those antennas you got on your roof, are they special D-Link antennas for wifi use or just normal antennas? - Where can I find more info?
I need a new signature... i'm bored of the old one!
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: UPS

Quote from: okrzynska
Hi Sean
Yea sorry mate I didn't notice you'd got it hard wired into the ring! Having just read what you've written it's a impressive setup you have but even so I personally wouldn't rely on just one power point (EG fuse in the fusebox going would leave the entire network stumped).
I never commented about the car battery - That was the other guys!
Be sure to let us all know how you get on with the UPS! It would be interesting to know how long it lasts when you test it etc.
Oh, btw, those antennas you got on your roof, are they special D-Link antennas for wifi use or just normal antennas? - Where can I find more info?

No matter how many sockets I use in the house the network would still be stumped if the fuse went in the fuse box as I only have one socket ring and one 30amp fuse in the house for the lot.
Fuses only blow when there is a fault (short) and I am not expecting any faults as I wired the thing.
The antennas on the roof are the Dlink ANT24-1400 14db directional antennas. They are pretty much made for that purpose. Bought them somewhere on the internet about 4 years ago. Cannot remember where but I know they cost me £115 each not including £30 each for the 2.4Ghz extension cables running into the access points, really heavy cable like garden hose! Then of course the DWL 900 access points at £60 each. The satellite dishes and tv aerial on the pole are nothing to do with the network, just another example of my obsession with everything technical!
Community Veteran
Posts: 4,729
Registered: 04-04-2007

Re: UPS

Sorry can I just add my 2p worth.
Peter was correct about using the right batteries. (OK not 100% with the reason) But it is important that use use batteries designed for UPS use, not a standard car battery. Hence why there are car batteries and leisure batteries.
Car batteries are designed for high current starts in low temperature conditions.
Leisure batteries are designed for regular slow deep discharge.
UPS batteries are designed for long term charging with occasional deep discharge.
I am not saying the the wrong batter will not work, but long term it will work out more expensive, likely to fail when you need it
Chilly
astarsolutions
Grafter
Posts: 393
Registered: 26-07-2007

Re: UPS

I use 6 1500-2000VA UPSs to run various bits of equipment but have run into the same problem of increasing their capacity so they run for longer.
I have never considered adding to the batteries but if your setup works I might give it a try, what I has always considered doing is connecting UPSs in series.
If the power goes down the first UPS kicks in and continues to run the equipment and other UPSs and slowly each one shuts down. In theory it seems like it would work but it isn't something I have ever had the nerve to try.
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: UPS

Running UPS in series is an interesting idea. I don't think it would be practical though. With the inefficiency of each UPS by the time it got to the first one half of the power would be wasted on running the UPS's and not the equiptment. I would imagine that a UPS would be more inefficient running of another UPS as the transformer in it wouldn't do a very good job with the modifed square wave comming from the inverter. Transformers work much better with a pure sine wave like that of the mains.
This is of course assuming that you would be using UPS's with modifed square wave invertors as pure sine wave inverters are much more expensive.
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: UPS

I have posted a photo of my newly modifed UPS at http://findabrush.seanbranagh.com/img/ups.jpg
At present it is connected to a 17Ah SLA battery from a portable jumpstarter aswell as its own 7.2Ah battery. I will be fully charging and discharging it with and without the extra battery over the next few weeks to test it before changing for a much larger external battery.
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Grafter
Posts: 393
Registered: 26-07-2007

Re: UPS

It will be interesting to hear the results, I would imagine you will have problems charging the external battery from the UPS but I may be wrong.
Community Veteran
Posts: 1,236
Registered: 02-08-2007

Re: UPS

The UPS is charginng both batteries perfectly and the extra battery is having a vast effect on the running time. Not sure by exactly how much as it has not had a full charge which I calculated would take about 30 hours. The problem is that the UPS is cuting out suddenly without any warning before the bateries run flat. I think this is probably due to the invertor over heating as it is not designed to run a large load for such a long period. This of course will be easily fixed with the addition of a few holes and a 12 volt 80mm fan to the top of the UPS case.