Spec me: UPS

[Quartz]

My UPS has failed. I've tried replacing the battery without success.

The failed one was 700VA.

The UPS is for home use: a single PC and three screens (see sig). I want battery backup and surge protection. I would prefer the UPS to be inline. I don't expect extended use - just enough to finish whatever I'm doing and shut down cleanly and to cover momentary power outages. It's likely going to be situated somewhere near my feet if it can't be hung from my desk, so some ruggedness would be appreciated.

 

[bledd]

What make was your old one? We have a lot of APC units in work.

They've been pretty solid tbh. A handful of failures, but not enough to put me off them.

 

[Armageus]

Either APC or Eaton would be my suggestion - have used various sizes of both at work (from 450VA line interactive APCs all the way up to 6000VA online Eatons) - in 10+ years I've had 1 APC fail (out of 30+ units)

Something like the APC Back-UP 1400VA would be ideal (and can be found for around £120):
http://www.apc.com/shop/uk/en/products/APC-Back-UPS-1400VA-230V-AVR-IEC-Sockets/P-BX1400UI

At ~300W-400W load you would get around 10-15 minutes of runtime
http://www.apc.com/products/runtimegraph/runtime_graph.cfm?base_sku=BX1400UI&chartSize=large

 

[EsaT]

Assuming wanting "normal" UK power sockets CyberPower BRIC would be one of the few.
https://www.cyberpower.com/uk/en/product/series/Backup UPS Systems/BRICs LCD

APC Back-UPS ES or what ever is its current name lacks any kind ventilation, which isn't good for cheap capacitors in its control electronics.

For DIN/Schuko plug there are more choises, but that would require different power cables.
And might as well go for IEC plugs.

 

[Phil2008]

I would buy a not very well known UPS because your paying quite a bit just for the name.. a few months ago I bought a online 2000VA / 1800W UPS from Powerwalker at £400.. If I had bought APC with the same specs Im guessing that would be closer to £1000 or more.

I dont use the ups in the "online" mode but the "line interactive" mode, as "online mode" uses slightly more power. But if the main voltage gets unstable it automatically switches to the online mode.

The UPS has been great so far and hasnt let me down.. If a power hungry powertool gets switched on that causes the mains voltage to drop about 10volts or more for a split second, the UPS switches over to the online mode with in 2-4ms. What I would like to know though, if the mains power voltage gets stupidly high, will the ups totally disconnect itself form the mains power, to save it from being damaged?

https://powerwalker.com/?page=product&item=10122042&lang=en

I have taken the cover off the ups to replace the fans for quieter ones, as the fans run 24/7 and its in my bedroom.. It looks one hell of a beast inside

 

[EsaT]

There's upper voltage limit for switching to battery so would expect UPS to disconnect itself from wall in case of high voltage.


Are those capacitors made by Aishi?
Images aren't sharp enough, but just look like those...

 

[Rroff]

APC Back-UPS

Sadly those Back-UPS units are proving to be a bit problematic - I've used APC extensively in the past without issues but I've a fair bit of experience now personally and indirectly professionally with the brick style ES and tower variants and the ES seem to be dying prematurely a lot and the tower style seems very sensitive to handling - if you get one of the tower style ones that works they seem great units but awhile back a lot weren't surviving transit (seems a bit better now so might have just been a bad batch or something).

 

[Phil2008]

There's upper voltage limit for switching to battery so would expect UPS to disconnect itself from wall in case of high voltage.


Are those capacitors made by Aishi?
Images aren't sharp enough, but just look like those...

The UPS flicks on to online mode when it gets ubove 250volts but its still connected to the mains power though, was just wondering if it ever got to like 300volts would it be intelligent enough to disconnect its self from the mains? Your spot on those caps are made by Aishi

 

[EsaT]

The UPS flicks on to online mode when it gets ubove 250volts but its still connected to the mains power though, was just wondering if it ever got to like 300volts would it be intelligent enough to disconnect its self from the mains? Your spot on those caps are made by Aishi

250V is only very minor difference.
I think there's something like 10% voltage tolerance for most mains voltage powered devices.
And there are UPSes which seem to have normally open relay in input and don't even power on without battery power.
So there could be ability to completely disconnect power circuitry from mains.

Don't know how cheap those Aishis are, but they're certain to be on cheaper end.
(just call them achoo in Chinese)
No doubt that's one of the reasons for that plastic cover, which acts also as airflow guide preventing heat from rising to top (above fans) and getting trapped there.

For minimizing noise per airflow finger guard made from metal wire would be still little better than those stamped grills.

Sadly those Back-UPS units are proving to be a bit problematic - I've used APC extensively in the past without issues but I've a fair bit of experience now personally and indirectly professionally with the brick style ES and tower variants and the ES seem to be dying prematurely a lot

Yeah, mentioned Back-UPS ES being bad with lack of cooling and cheap crap capacitors.

 

[ANDARIAL]

I would buy a not very well known UPS because your paying quite a bit just for the name.. a few months ago I bought a online 2000VA / 1800W UPS from Powerwalker at £400.. If I had bought APC with the same specs Im guessing that would be closer to £1000 or more.

I dont use the ups in the "online" mode but the "line interactive" mode, as "online mode" uses slightly more power. But if the main voltage gets unstable it automatically switches to the online mode.

The UPS has been great so far and hasnt let me down.. If a power hungry powertool gets switched on that causes the mains voltage to drop about 10volts or more for a split second, the UPS switches over to the online mode with in 2-4ms. What I would like to know though, if the mains power voltage gets stupidly high, will the ups totally disconnect itself form the mains power, to save it from being damaged?

https://powerwalker.com/?page=product&item=10122042&lang=en

I have taken the cover off the ups to replace the fans for quieter ones, as the fans run 24/7 and its in my bedroom.. It looks one hell of a beast inside

Maybe i am going blind but where are the batteries?

 

[Rroff]

Maybe i am going blind but where are the batteries?

IIRC they are on the other side of the case behind the mainboard.

 

[ANDARIAL]

BlimeyMust be a huge box then

 

[Phil2008]

It's the size of a small pc

 

[Sasahara]

A word of warning if anyone else decides open up a UPS, be extremely carefull. Phil2008 may know what he's doing.

The caps in a UPS can carry a dangerous charge long after it's been disconnected from the mains.

 

[Phil2008]

A word of warning if anyone else decides open up a UPS, be extremely carefull. Phil2008 may know what he's doing.

The caps in a UPS can carry a dangerous charge long after it's been disconnected from the mains.

I dont really know what Im doing, but the batteries has to to changed every few years anyway.. Like I hate opening up UPS's mainly because until you have disconnected the batteries, the UPS still has power running through it. So 1 wrong move and the UPS is toast.

The APC UPS's are not bad as you can disconnect the batteries before opening up the UPS, but with mine you have to open the UPS before you can disconnect the batteries and careful not to short anything as you do...Plus because my UPS is 1800watts, it give off a nasty spark and makes you jump when reconnecting the batteries back up to the UPS.

So to be honest power in the caps are the least of my worries.

 

[Phil2008]

The electric tonight is obviously not in high demand in my area, as the incoming voltage on my UPS says 253vollts. So it has flicked over to online mode so it can change the output voltage to 240.

My old line interactive UPS wasn't as sensitive as this new one, I think that would change the output voltage when it had gone over something like 270volts

 

[Rroff]

So to be honest power in the caps are the least of my worries.

The capacitor is gonna be the bit that kills you - the discharge current can be significant and with inductance and other things in the equation the charge on them might be at considerably higher voltage than you'd expect :s (or something like that if I knew what I was talking about).

 

[EsaT]

The capacitor is gonna be the bit that kills you - the discharge current can be significant and with inductance and other things in the equation the charge on them might be at considerably higher voltage than you'd expect :s (or something like that if I knew what I was talking about).

Output voltage from capacitor connected to DC is same as input voltage.
It's RLC series connection in its resonant frequency AC which can have higher than circuit input voltage over capacitance and inductance as part of its "normal operation".
(voltage over capacitance and inductance are just of opposite polarity cancelling each others from perspective of whole circuit)

And while capacitor with higher stored energy can certainly hurt lot, it still gives out single short pulse, which isn't as dangerous as AC.
Actually defibrillators work by giving such single short pulse...
(to try to "reset" heart)

 

[Phil2008]

The customer support says leave 15mins with the power switched off before opening.

 

[EsaT]

The customer support says leave 15mins with the power switched off before opening.

Circuitry with bigger capacitance usually has resistors to drain it in certain time when not connected to power.