UPS (Uninterruptible power supply) - appreciate a little help

[Dazzler]

Thanks for reading, I'd appreciate a little help on UPS's and see if they can solve me a problem.

I help out with the timing system at the local triathlon club and need to power a wi-fi router, a laptop, a monitor and printer for about 4-5 hours (at most) (although monitor maybe just 1 hour). Would a UPS do the job? Is it as simple as adding up the watts and dividing into the UPS capacity? e.g. Laptop 40W, Monitor 60W, Router 10W = 110W. so 1,000VA UPS would give 1,000/110 = 9 hours - call it 6 by time inefficiencies eat away at time? All discharge graphs seem to have times much lower than this.

A bit loathe to use a petrol generator.

Can anyone calibrate me on real-world usage times?

Thanks in advance.

[200mwaterresistant]

Most UPSs are only designed to power a single computer for about 15 minutes in event of power failure - enough to be alerted to the power cut and safely shut the machine down.

They are also not 100% efficient so your calculation may be quite a bit off.

I have a 1400 here which just maintains our router and a couple of other similar low power things and it will last for 5-6 hours, but the draw on it is very small.

They all use Yuasa sealed lead acid batteries though, so there's no reason you couldn't go mad max and have flying leads rigged up to connect to as much of a battery array as you need to supply what you're after, but you are essentially just using the UPS as an expensive inverter. Better off with a car battery, suitable charger for home, and an actual inverter if you really want to stay away from a gennie.

[swanbourne]

I had a UPS (not a cheap one either) which had a self-test utility which ran every Saturday. It always passed the self-test but the only time it was needed, it failed.

Eddie

[ALindsay]

Most UPSs are only designed to power a single computer for about 15 minutes in event of power failure - enough to be alerted to the power cut and safely shut the machine down.

They are also not 100% efficient so your calculation may be quite a bit off.

I have a 1400 here which just maintains our router and a couple of other similar low power things and it will last for 5-6 hours, but the draw on it is very small.

They all use Yuasa sealed lead acid batteries though, so there's no reason you couldn't go mad max and have flying leads rigged up to connect to as much of a battery array as you need to supply what you're after, but you are essentially just using the UPS as an expensive inverter. Better off with a car battery, suitable charger for home, and an actual inverter if you really want to stay away from a gennie.

I agree, a UPS is not intended for what you require.

[Barry]

I time bike races and you will need more juice than that, with a generator as back up, you can noticeably hear the generator pick up the load when the printer is called for.
Genny on a long extension (don't forget it needs an RCD at source) would be best.

[MikeB687]

Agree with the above, I bought one after losing a nearly finished Vat return it'll give you time to save & shut down but won't keep your system going for hours.

[MB2]

A decent UPS like we have holds the servers and network up for a good while but it weighs more than a small generator. A small generator will also likely struggle with a printer (unless ink jet) we have a small Honda “suitcase” generator it will run a couple of servers but the kettle (by itself) stops it dead. Also beware with generators if the current isn’t “smooth” (the Honda is) then you will need a small UPS between the generator and the IT kit. Even the big generator we have struggles with a laser printer but runs many PC/monitors (all via UPS).


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[Tokyo Tokei]

Laptop should run off its own internal battery for a few hours.

Although inefficient to convert 12VDC to 240VAC only to have the appliances transform it back to low DC you might be able to provide enough power from an inverter run off a car battery.

[catch21]

If you’re going for a small generator then, as above, I’ll second that you’ll need a good one. I’ve smoked sensitive equipment with the rough and ready voltage from a cheap one. I’ve just replaced the batteries in an APC smartups 1000 at the cost of over £100 and I can vouch for the fact that even new ones discharge frighteningly quickly when under load.

[jcm3]

Most (none that I know of) UPS systems are not designed to be run at 100% capacity for extended periods of time. In fact, 50% of capacity for an hour would be a lot more than any of them have planned. 15 minute run times are the most a typical UPS is stretched to. Long duration UPS systems are more common in industrial applications, even then you want to look at systems rated 50% or less of the duty load.

Honda builds a small, super quiet generator for less than an industrial UPS would cost. Honda EU20I

[Mr Pointy]

As others have indicated a UPS probably won't do what you need as in general they are short duration backup devices. If you don't want to use a generator then you could look at putting together a battery & inverter system: this could provide the run time you need but it's likely to be expensive. These systems are used in the camping/caravanning & the solar/off grid domestic power markets so do some research in those areas. A quick Google threw up pages like this:

http://www.selectsolar.co.uk/cat/202/guide-to-inverters
http://www.dcacpowerinverters.com/faq.htm (see the "how long can I run" dropdown)

In theory it looks like a 200W load for 5 hours could be supplied by a 100Ah battery but that's without any safety margin. A few other points to consider:

1) For preference look at a sine wave inverter, not a modified sine wave one.
2) The printer type will be important. Ink jet probabably yes, laser would be difficult.
3) Watch the peak/start up capacity of the inverter - especially if it's a laser printer.
4) Car/lorry batteries hate being discharged so look for leisure/deep cycle batteries - check caravan suppliers.
5) Keep the battery to inverter run a short as possible & use huge cable to reduce volt loss.

It's unlikely this setup is going to cost less than £300-400 so you're definately heading towards the same cost as a generator. If you do go for one then ask the camping community about good quite ones - Honda always get mentioned.

Note that HSS hire out Honda generators for £20 a day. I can't see you finding a more economical solution than that.
https://hsstoolshop.co.uk/portable-q...ire-1316-p.asp

[MB2]

Most (none that I know of) UPS systems are not designed to be run at 100% capacity for extended periods of time. In fact, 50% of capacity for an hour would be a lot more than any of them have planned. 15 minute run times are the most a typical UPS is stretched to. Long duration UPS systems are more common in industrial applications, even then you want to look at systems rated 50% or less of the duty load.

Honda builds a small, super quiet generator for less than an industrial UPS would cost. Honda EU20I

We have a EU10i which is 1kw - it will run 2 servers and a PC or 2 but being only 1kw the kettle kills it. It is an inverter generator so it can run a PC directly but I would still suggest putting it in line with a small UPS as it is surprising how often the petrol can get low or they can stumble. They are great though very light weight and quiet and a smooth output. You can also transport them in the car full (provided they are upright of course) but do make sure you accurately assess the load.

Hiring one first makes great sense to test the solution before buying or even regularly hire given it will be a known schedule (ours are used for protection against power cuts so completely unpredictable usage !)