UPS

Robin9

I am thinking of installing a small UPS for my PC

I can understand that it will be fine for dips (which is my problem) and even short mains outages or a few seconds .   What happens for a sustained failure of several  minutes - do the batteries run flat or does it auto-shutdown ?

Neil_Jones

Think of a UPS as a large battery.  Like all batteries they will eventually run out of juice.

When the batteries in a UPS run low on juice because the power from the mains has been out for a while, they send a shutdown signal to the computer they're connected to, often via USB.  Sometimes its by their own software or Windows can use its own driver.

steviebabes

They will shut down your computer before the battery gives out. The idea is that you save any open documents before the auto shutdown.

John_Gray

Robin9 said:

I am thinking of installing a small UPS for my PC

The electricity supply in most parts of the UK is sufficiently reliable to make the use of a UPS largely unnecessary.  Do you have particular circumstances which make a UPS necessary?

matelodave

John_Gray said:

Robin9 said:

I am thinking of installing a small UPS for my PC

The electricity supply in most parts of the UK is sufficiently reliable to make the use of a UPS largely unnecessary.  Do you have particular circumstances which make a UPS necessary?

It depends where you live - we get drop outs at least once a month sometimes 2-3 a day and it pretty irritating when the router shuts down and reboots and everything else has to catch-up. We dont really live everso far off the beaten track - the A10 trunk road is just the other side of the river to us but our power supply is pretty ropey.

We use laptops so we dont actually lose stuff because the battery keeps it going but a NAS drive losing power or any other data handling stuff doesn't like it.

I've now installed a small 12v UPS to keep the router going and our Optical Line Terminal has an inbuilt back-up batter which keeps it going for a couple of hourse.

MattMattMattUK

You need to work out the load of your devices which you will connect to it. PC, monitor, router etc. as a general rule printers are not worth connecting to a UPS and a laser printer, if used while on backup power will probably kill the UPS. Once you have that you look at the capacity of the UPS and can calculate your runtime, you can the decide how much you want based on the levels of black/brown out you regularly receive.

onomatopoeia99

John_Gray said:

Robin9 said:

I am thinking of installing a small UPS for my PC

The electricity supply in most parts of the UK is sufficiently reliable to make the use of a UPS largely unnecessary.  Do you have particular circumstances which make a UPS necessary?

I'm not the OP but:
In 2019 I had 13 grid failures (only recorded from the start of July)
In 2020 there were five
So far this year there have been two.
One of the reasons I got a Tesla Powerwall when I had my solar panels installed is that it doubles as a massive UPS.  

Robin9

John_Gray said:

Robin9 said:

I am thinking of installing a small UPS for my PC

The electricity supply in most parts of the UK is sufficiently reliable to make the use of a UPS largely unnecessary.  Do you have particular circumstances which make a UPS necessary?

Its a rather special amp - Bose PM8500 - rather than a computer and runs a Church sound system.  It runs on permanent standby (due to its location).  

The dips are very small - a fraction of a cycle - rather than complete outages and are probably Grid issues rather than local loss of supply.  

From what I can understand an online UPS of about 2.5 or 5.0kVA will be fine. 

MattMattMattUK

Robin9 said:

John_Gray said:

Robin9 said:

I am thinking of installing a small UPS for my PC

The electricity supply in most parts of the UK is sufficiently reliable to make the use of a UPS largely unnecessary.  Do you have particular circumstances which make a UPS necessary?

Its a rather special amp - Bose PM8500 - rather than a computer and runs a Church sound system.  It runs on permanent standby (due to its location).  

The dips are very small - a fraction of a cycle - rather than complete outages and are probably Grid issues rather than local loss of supply.  

From what I can understand an online UPS of about 2.5 or 5.0kVA will be fine. 

Whilst that is not the cheapest amp a 5kVA UPS could easily cost more than the amp does.

If it were me and budget was a constraint, which I imagine it is, then I would be looking at a high quality surge protector and turning if of when not in use. If where the unit is positioned makes they difficult then I would suggest repositioning the unit, rather than spending £3k or more on a UPS.

ann_droid

Hi
Here's a daft idea.........

Heedtheadvice

Mmm, yes daft idea

If the mains dropout is only a part of a cycle (assume you have measured that with a transient recorder of mains monitor recorder?) then that Bose amp could really have a problem as the power supply reservoir capacitor(s) and smoothing capacitors should have enough storage in them to keep it running for that duration.

Is it a trip that feeds it that is switching off?

If it really is a short duration outage then you do not need a large UPS battery, just one that will hold up a few seconds. It needs to be able to supply that peak current for a few seconds so that determins the short term energy storage requirement (provided the UPS spec for short term is a second or two that will suffice, battery backup is often 15mins or so and that keeps the price up, the longer the higher the cost).

Of course the continuous (no fault) power handling needs to be sufficient too.

It really requires more info regarding your amp configuration to know the actual continuous and peak power requirement. Although rated at 4kW (that's a lot of power for a church!) actual continuous power demand will probably be a lot less even if the particular configuration is ignored.

Could be worth looking at a UPS easily available from CPC https://cpc.farnell.com/powerwalker/10122119/ups-vfi-3000-cg-pf1-iec-uk/dp/CS31631?st=UPS There are of course other suppliers but that one is a quality unit that gives pure sine wave output and fast switching between bypass (normal mains) and battery backup and under £700 +vat.

If you can refine power demand you could get a smaller/cheaper one.