Jimmy wrote:
I've built a "basic" PC desktop, I mean 150-200w max for "basic" including
my monitor, with a Corsair CX450 PSU (OEM CWT RPS0053) with active PFC. Now
I need a UPS but my budget isn't high to get the best (eg. an online UPS) so
I'd like to buy a UPS with the best quality/price relationship for my goals
and equipment within 180USD. AFAIK I need a UPS that generates a pure
sine wave during a blackout because of my PSU's active PFC, now let's define
my goals.

My worst scenario is when it's raining hard because blackouts occurs randomly,
eg. last time it rained there were 3 blackouts within 30 minutes and then no
more ones though it kept on raining for hours. My "limit" is 2 close blackouts,
I mean I've to be able to shut my pc off correctly during the 2nd blackout
then... I'll just wait for better weather time Well my electrical system
suffers brownouts oftenly too but I guess a line-interactive UPS, I mean with
AVR, will be a solution for that.

That said please tell me how much minimum power (VA / W) has to generate an
UPS to get my goal, I mean the worst scenario I've described above. Then please
tell me if an UPS must have other specifications. Finally please suggest me
some UPS models to buy within 180USD that fit my personal case.

If you put the computer and monitor on a single outlet strip,
then plug it into a Kill-O-Watt meter, you can get both a W and a VA
measure at the touch of a button. You run Furmark and Prime95 on the
computer, to max the power demand, then take a reading. This gives
you an accurate value fo total W and total VA. For an active PFC device,
you expect the W = VA since PF ~= 0.99, but the meter leaves nothing
to the imagination. The LCD monitor is unlikely to be PF 0.99, and would
be a tiny contribution of PF = 0.65 loading.

https://www.amazon.com/P3-P4400-Elec.../dp/B00009MDBU

On modern Intel processors, they can turbo above TDP, so TDP isn't
necessarily a complete characterization. Just a word of warning not
to "shave it too close".

There is also the possibility of buying a "really cheesy" UPS,
one where it doesn't deliver the rated power, and to get
some runtime, there's a good chance your capacity (max Watts expected)
will be covered anyway.

Since you didn't give any indication of what's in the PC,
it's hard to give ballpark numbers. I can illustrate with
my PC here.

Video card manuf rated 180W draws 180W (modern cards use a power limiter)
CPU manuf rated 130W draws 156W (ATX12V inefficiency is the difference)
My CPU has turbo turned off
Motherboard allocate 50W
HDD look it up 8W to 15W HDD, 2.5W SSD

Total 375W

My monitor might be 35W or so, because it's tiny by modern
standards. The new machine got a $100 monitor, because the
hardware for the basic computer cost so much ($800 worth of RAM).
RAM sticks are around 1W apiece (standby value). I would
bundle the RAM loading, into the motherboard number. Exceptions
for monstrous server devices with FBDIMM, where the loading
is significant.

So now we're at 410W, and we have a budget of $180 USD.

*******

APC BR1000MS 1000 VA Pure SineWave 10 Outlets 2 USB Charging Ports Back-UPS $147

https://www.newegg.com/apc-br1000ms-...82E16842301698
https://www.apcguard.com/BR1000MS.asp

1000 VA / 600 Watts
Battery Type Sealed Lead Acid
Battery Run Time 600W: 3.7 minutes
400W: 8.0 minutes
200W: 20.5 minutes
Replacement Battery APCRBC160
RBC Quantity 2
Expected Battery Life (years) 3 - 5

Topology Line Interactive
Waveform type Sine wave
Boost AVR: Correcting low voltages without discharging the battery.

Net Weight 22.49lbs. (10.2KG)

They're careful to not give any ratings on the battery pair
https://www.apc.com/shop/us/en/produ...60/P-APCRBC160

CyberPower CP1350PFCLCD 1350 VA / 810 Watts PFC Pure Sine $199
Weight 20.30 lbs.

CyberPower GX1325U 1325 VA 810 Watts 10 Outlets UPS, Pure Sine $180
Weight 20.30 lbs

CyberPower CP1000PFCLCD UPS 1000 VA / 600 Watts PFC compatible Pure Sine $155
Weight 15.90 lbs.

Pick the middle one.

CyberPower GX1325U 1325 VA 810 Watts 10 Outlets UPS, Pure Sine $180

https://www.newegg.com/cyberpower-gx...82E16842102238
https://www.cyberpowersystems.com/pr...ackup/gx1325u/

1325 VA / 810 Watts
Battery Type Sealed Lead Acid
Battery Run Time 600W: 5 minutes
400W: 9 minutes
200W: 22 minutes
Battery Quantity 2
Battery Size 12V 7Ah (for 2-pak?)
Battery Type SLA
Replacement Battery Cartridge RB1270X2A ($70USD for 2-pak)

Topology Line Interactive
Energy Saving GreenPower UPS Bypass (means similar to SPS, no constant fan)
Waveform type Sine wave
AVR Single Boost

EMI/RFI Filtration Yes
Phone / Network Protection RJ11/RJ45 1-In / 1-Out (Combo)
Surge Suppression (Joules) 1030 J

Weight 20.30 lbs

The feature set on these units, is pretty similar. You
might want to compare the connectors on them. The APC has a
crazy data port (looks like an RJ series), which comes with
an adapter cable with some sort of USB on the other end. Both
units have supervisor cables, and these cables ("data port")
allows software on the PC, to do a clean shutdown of the
PC when the battery is partially drained.

I picked the middle one to try to get more runtime. But
they're really within spitting distance.

Notice also, that the word "sinewave" is treated in a cavalier
manner. They like to combine "sinewave" with "won't cook active PFC
goods", which with modern equipment, might still be met with a
stepped sine waveform. You need stronger language such as
"Pure Sine" to signify something a power company would be
sending to you as a waveform. It's always possible,
to meet a price point, these are stepped sine units.

But that'll give you some idea what is available at your
price point. These are not bottom tier UPS. $50 buys you
the "will stay up for a second if the lights blink" UPS.

Read the reviews to see how many catastrophic failures
the designs have had. The warranty on these units, is
generally "catch me in court, dummy" material. The companies
will generally be non-responsive if you claim their unit
smoked your gear. At a bare minimum, *make sure* to plug
these piles of crap directly into the wall. One
of their favorite warranty denials is "you used an extension
cord". The units must be fed from robust wall sockets.

Paul