As a desktop PC enthusiast, there are times you’ll look upon your notebook-toting cousins-in-tech with their battery backup and curse — usually just when the mains power goes off and you’ve lost your university assignment or, worse, all of that awesome work on Metro: Last Light. But that’s where an uninterruptible power supply (UPS) can help — not necessarily to keep you fragging through the night, but at least to gracefully shut down your PC so nothing goes missing. But how do you pick the right model and what do the specs mean?
A UPS is essentially a battery backup, or more precisely a short-term AC inverter. When the AC mains is fine, it provides nothing more than surge protection and in some models, added voltage regulation. But, the instant the mains fails — and we’re usually talking within ten milliseconds — it switches over to backup power in the form of one or more sealed-lead-acid (SLA) batteries (these are similar to your car battery but with a gel electrolyte, not liquid sulphuric acid). The AC inverter turns the 12 or 24VDC battery voltage into 230VAC mains voltage to feed your tech.
Inverters and batteries
UPSs often have lots of extras but you can boil down the specs into two major criteria — the capacity of the inverter to power a load and the capacity of the batteries to keep it running.
An inverter is like a car engine — it delivers a certain maximum power output. Just as you can’t expect a three-cylinder engine to power a ‘B-Double’ truck, a UPS has to be at least rated to the electrical load you want it to drive.
Power capacity is measured either in volts-amps (VA) or watts (W) – VA is the AC or ‘apparent’ power rating; watts is the DC or ‘actual power used’ rating. See the ‘What is Power Factor’ box for more details, but bottom-line, look for the watts rating on consumer-grade UPSs. Not all UPSs publish this up-front since it’s the smaller number — in that case, take 60% of the VA figure as a fair approximate of the watts rating, the real load the UPS can handle.
As for batteries, the rule seems simple enough: the bigger the battery or the more batteries it has, the longer the inverter keeps running. But like most things, it’s not always that simple.
Let’s break it out quickly:
- SLA batteries are heavy — add in two batteries and a UPS hits ten kilos real quick.
- The battery has to have sufficient capacity to handle the demands of the inverter.
- Bigger battery capacities last proportionally longer than smaller ones.
How to choose
A UPS watt rating must at least match the power draw of the gear you want powered. How long a UPS runs for depends on whether you just want a graceful shutdown or to keep going.
That ultimately sets the size, capacity and price of the UPS you need to choose.
What the specs mean
Automatic Voltage Regulation is designed to improve the quality of the AC mains voltage, raising it to the right level during brownouts and dropping it during surges. All UPSs have AVR when running on battery.
Modified/simulated sinewave output:
Australia’s AC mains voltage ‘alternates’ in the form of a 50Hz sinewave. Making an AC inverter do this is expensive so cheaper models use a ‘modified’ or ‘simulated’ sinewave that’s a series of rising and falling voltage steps. It’s not the real thing but for many devices, it’s close enough. Waveform-sensitive devices may struggle with it, though. All of the units we tested were mod-sine designs.
What is Power Factor?
Power Factor (PF) is the ratio between this real ‘watts’ power used to the apparent VA power required. An incandescent lamp is purely resistive, so has a PF of 1.0 — it uses all the power it requires. An induction motor may have a PF of 0.5 where half the power (the ‘apparent’ power) disappears back into the electricity grid, but still has to be supplied for the motor to run. That’s why inductive loads are always more difficult for UPSs/inverters to power — they need access to more power than they actually use.
APC Back UPS Pro 550
Good performance and well-featured, but it’s not cheap.
Rating: 4 stars out of 5
The Back UPS Pro 550 wasn’t just the smallest UPS we saw this roundup, it was also the most expensive of the sub-1000VA models and not far behind a couple of the 1200VA category as well. APC is arguably the ‘Rolls Royce’ brand when it comes to consumer-grade UPSs, so it doesn’t surprise us you pay a bit extra. However, that said, it outlasted its category rivals, topping 17mins 38secs — that’s a decent effort from one 12V/7Ah SLA battery.
APC’s PowerChute USB software is clean and user-friendly, giving you all the information you need. But like all good software, it can be set any number of ways from automatic shut-down on power fail to automatic self-testing. As soon as it switches to battery, it starts emitting four beeps every 30 seconds as a warning.
While there are six IEC320 sockets here, only three are battery backed — the rest are surge-protection only, so it’s really a single-user model. It also has a unique feature where one of the battery backed IEC sockets can act as a master socket controlling two of the surge-only ports. If the master socket goes off, so do the other two.
If there is a downside, other than price, it’s the 12-hour battery recharge spec, which is four hours longer than any other model we saw. That said, slower charging is said to be better for long-term reliability, so it maybe a case of ‘swings and roundabouts’.
Conclusion: Delivered the best runtime from a single 7Ah battery, but much more expensive than similar models.
APC Back UPS 1100
Has few features, but it cranks out power for a bargain price.
Rating: 4 stars out of 5
By contrast to APC’s Back UPS Pro 550, there are no airs or graces with this Back UPS 1100 — it’s just a real workhorse of a UPS. It has no USB connection, no software, no LCD screen. It’s also another to use IEC connectors rather than Australia’s standard GPO (general purpose outlet, also known as standard ‘AS3112’), but the 1100 is an old-style basic featured UPS that gives you plenty of runtime for your buck. More precisely, we managed just over 46mins before it gave out running our 110-watt PC/monitor test rig. The two 12V SLA batteries are smaller 7Ah capacity units compared with Jaycar/Digitech’s 9Ah so we think the runtime is on the money. Still, at 12kgs, moving it isn’t something to be done very often.
Having IEC320 sockets rather than AS3112 GPOs makes it less appealing, but that no doubt also helps lower costs, since APC can ship this unit around the world and just modify the AC output voltage to suit. What’s more, there are six IEC sockets, all battery backed, so you’ve got at least three PC/monitor combinations covered, right there.
In the end though, the key feature is the price — at $210 on the street, it’s a tight contest for the most output power and battery runtime per dollar between this and Jaycar’s Digitech MP5207. For extra user features, frankly, the Back UPS 1100 has nothing. But we can see it being like a well-worn ute — not much to look at, but it’ll likely be still running when fancier boxes have carked it.
Conclusion: This one reminds us of a Holden ute — no fancy bits, just plenty of power at a hard-to-beat price.
A decent, no-nonsense budget UPS.
Rating: 4.5 stars out of 5
This Belkin 600VA UPS is an example of the popularity of promoting the larger VA rating. In the instruction manual, it’s listed as 600VA/360-watts. It provides four IEC sockets (three with battery backup and all with surge protection) and although there’s no LCD screen, it comes with USB connection and PC software (but why we need 284MB of it is anyone’s guess). The software isn’t exactly the richest in providing info, either — there’s no load percentage, no battery voltage or capacity remaining.
But that said, the Belkin 600VA really did surprised us, lasting just on 17mins with our 120-watt PC/monitor load. With the standard 12V/7Ah SLA battery used, that’s still a pretty decent result, particularly given how much APC wants for its Back UPS Pro 550. It has a very quick switchover on power failure (no greater than six milliseconds), however, the inverter circuitry has a bit of a buzz to it when it kicks in. The UPS also adds RJ11 phone connection protection and backs it up with a $100,000 worth of connected product insurance, more than anyone else (although, not reason alone to buy it).
No-one loves audible alarms but the Belkin unit has four alarm modes, including beeping every ten seconds when on battery power. Its six-hour charge time is also the fastest we saw.
All up, it’s quite reasonable value for a UPS you’ll find on the street for around $120.
Conclusion: No LCD screen, but gives decent runtime for what was the cheapest UPS we saw.
CyberPower BRIC BR650ELCD
Full of features, decent performance at a nice price.
Rating: 4.5 stars out of 5
Price: $149 ($120 online)
CyberPower’s BRIC series is appropriately named, given it’s a brick-styling (as opposed to the increasingly common mini-tower designs), but for its price, its good value. Coming in just under the $150 mark, its 15mins25sec runtime easily outlasted the Digitech MP5205 despite featuring the same capacity battery and came close to the Belkin 600VA model. However, the BR650ELCD also has a decent LCD panel and USB connectivity. The fact it has six GPOs ready to go rather than just the more globally-universal IEC320 sockets will likely make it more expensive to build, but certainly much more versatile. The downside is only three of those GPOs have battery backup — the other three are surge arresting only. It also delivers RJ11/RJ45 in/out ports for phone or data protection, plus there’s a USB power port too. Of course, you can just plug in your AC USB adapter, but the direct port is slightly more efficient. One other important bonus was its quiet operation — pretty close to whisper-quiet compared to some of the ‘bar fridges’ we heard.
CyberPower uses the PowerPanel app for this and its bigger Value1200ELCD model. The app is nicely put together, easy to read and like all good apps, gives you a decent array of controls. Given the other models around this 550-650VA rating, the BR650ELCD delivered the right mix of features, performance and price. Speaking of which, you’ll find this one at major retailers for around $149, but we’ve seen it online from the likes of Mwave (www.mwave.com.au) for under $120. At that price, it’s a no-brainer.
Conclusion: Aussie GPOs, decent 15+mins runtime, good software and a $120 street price make this hard to beat.
CyberPower Value 1200ELCD
High-power capacity, but short on runtime.
Rating: 4 stars out of 5
The Value1200ELCD from CyberPower has plenty of horsepower under the bonnet, able to handle up to 1200VA/720W and with four standard GPO outputs, you won’t be fighting for a spot on this one. It features the same software and LCD panel as the smaller BR650ELCD, but doubles the battery capacity with two 12V/7Ah SLA batteries. Being a high-powered unit, there is a bit of a buzz from the inverter while it’s running, but the cooling fan in the back was more noticeable when it fired up.
What surprised us a bit more was the battery runtime. Even with our fairly modest load, it only managed 23mins05secs — that’s quite a way back compared with the Digitech MP5207 and APC Back UPS 1100. Still, CyberPower says it’ll only manage 10mins anyway at half load (360W), so our result is within reason. It’s worth noting that this is only $5 more expensive than APC’s Back UPS Pro 550 but with double the output capacity and overall, there’s plenty to like here, with its $75,000 connected insurance, standard GPOs, AVR and internal current limiting (preventing UPS overload).
Ultimately, having the ability to handle heavier loads means these high-powered UPSs are less efficient at smaller load levels, compared with smaller UPSs. That said, with the Back UPS 1100 hitting 46mins and the Digitech MP5207 lasting more than an hour, our Value1200ELCD test unit was a bit off the pace.
Conclusion: For such a sizeable unit, the runtime from those two 7Ah batteries was a bit disappointing.
Compact with good features but low on runtime.
Rating: 3.5 stars out of 5
There’s a real price difference between the Digitech MP5205 and MP5207 UPSs from Jaycar Electronics and in the end, these two were bookends on our test results. The MP5205 features the standard single 12V/7Ah SLA battery and a quite decent orange LCD panel with plenty of information (especially given the price). In fact, it’s the same panel that appears on the higher-capacity MP5207. It has USB connectivity and comes with software that does the usual tricks such as auto-shutdown on power fail (although why it bothers with a serial number is beyond us). However, the software is a bit rough around the edges and not particularly user friendly (serif fonts on software never look great).
It comes with just two outputs but they are standard Aussie GPOs, which helps, but arguably the greatest drawback here is the runtime. At just over ten minutes, you’ve got enough time for a graceful PC shutdown, but not a whole lot left over and given the eight-hour recharge time, it won’t handle too many close-occurring blackouts. Jaycar doesn’t mention if this unit has AVR on its AC leg.
Obviously, instigating a power failure for a labs test isn’t a safe thing, so we simulated it by turning off the power to each of the UPSs. However, a couple of times, our MP5205 test unit failed to trip and fire up the AC inverter, knocking out our test PC. It’s not the most scientific of tests, but we didn’t see this happen on any other unit we tested.
Conclusion: Has all the features, but software lacks a little polish.
Lacks for smooth corners, makes up in performance.
Rating: 4 stars out of 5
Digitech is Jaycar Electronics’ house brand, and it takes the award for the longest-lasting UPS we tested. Packed with two 12V/9Ah SLA batteries, we had to wait 1hr06mins for this one to fall over — that’s an exceptional result. Further, it’s rated at a heavy 1500VA (or 900W), which meant our 120-watt PC load really didn’t overly tax those batteries, resulting in that one-hour-plus time. Its USB connected and comes with the same rough-but-passable software as the MP5205 with good data on power features inside the unit. The LCD panel is also the same and delivers lots of information — that said, we’re a bit ‘iffy’ about some of the data we saw from it. For example, the battery percentage sat on 90% for around 40mins, then started dropping down steadily. What disappointed us a little was having only two GPOs to play with — sure, a six-way powerboard makes short work of that issue, but given the $299 price tag and the size of the unit, extra outlets would’ve been a nice touch. The anchored AC cable didn’t overly impress either. And it has to be said, our test unit buzzed quite noticeably, enough for someone in the office to call it a bar fridge!
But overall, despite being the most expensive model we tested, it was also clearly the longest lasting and highest-capacity unit we saw. You wouldn’t get an hour of solid gaming from it but for light-duty work, you’d get close. But here’s the real benefit — this unit would survive quite a few blackouts before its batteries required serious recharging.
Conclusion: Most expensive unit we tested but outlasted everything else for runtime by a decent margin.
Uninterruptible Power Supplies — How they compare
|Model||APC Back UPS 1100||APC Back UPS Pro 550||Belkin 600VA||CyberPower BR650ELCD||CyberPower Value 1200ELCD||Digitech MP5205||Digitech MP5207|
|Capacity – Volts-Amps (VA)||1100||550||600||650||1200||650||1500|
|Capacity – Watts (W)||660||330||360||390||720||390||900|
|AC outputs (number x type)||6 x IEC||6 x IEC||4 x IEC||6 x GPO||4 x GPO||2 x GPO||2 x GPO|
|AC outputs on battery backup||6||3||3||3||4||2||2|
|AC output voltage (VAC)||230||230||230||230+/-10%||230+/-5%||230+/-10%||230+/-10%|
|Output waveform||Modified Sine||Modified Sine||Modified Sine||Simulated Sine||Simulated Sine||Modified Sine||Modified Sine|
|Battery voltage/capacity (V/Ah)||12/7 (x2)||12/7||N/A||12/7||12/7 (x2)||12/7||12/9 (x2)|
|Typical recharge time (hrs)||8||12||6||8||8||8||8|
|Ratings||4 stars||4 stars||4.5 stars||4.5 stars||4 stars||3.5 stars||4 stars|