There’s a unique kind of dread that accompanies the sudden, unexpected silence of a power outage. I remember one particular afternoon, deep in the throes of a critical project with a deadline looming. The sky outside had turned a bruised purple, and a storm was brewing, but I was in the zone, typing furiously. Then, a flicker. The lights blinked once, twice, and then plunged my office into darkness. The hum of my desktop computer vanished, replaced by an unnerving quiet. In that instant, I knew an hour of unsaved work was gone forever. It wasn’t just the lost time; it was the broken concentration, the frustration, and the scramble to recover. This scenario is all too common. In our digitally dependent world, a momentary loss of power can mean corrupted data, damaged hardware, or a dropped connection during a crucial video call. It’s not just an inconvenience; it’s a genuine threat to our productivity and the longevity of our expensive electronics.
- SURGE PROTECTION AND BATTER BACKUP: UPS offers protection during damaging surges, spikes or power outages and USB communications for notifications and controlled shutdown with free software download.
- 8 OUTLETS: It has 4 surge only and 4 battery & surge outlets; 2 are widely spaced to accommodate transformer-block plugs without covering adjacent outlets.
- TEL/NETWORK DATA LINE PROTECTION: Surge protection for RJ45/11 for data line surge protection.
What to Consider Before Buying an Uninterruptible Power Supply (UPS)
A Uninterruptible Power Supply (UPS) is more than just a glorified power strip; it’s a key solution for ensuring digital continuity and peace of mind. At its core, a UPS is an insurance policy for your electronics. It provides a seamless transition to battery power the moment AC power is cut, giving you a critical window to save your work and safely shut down your equipment. Beyond preventing data loss, it also acts as a shield. The grid isn’t always stable; sags, surges, and spikes in voltage can silently degrade and ultimately destroy sensitive components in your computers, TVs, and networking gear. A quality UPS conditions this power, absorbing the harmful fluctuations and delivering a clean, stable current to your devices, significantly extending their lifespan.
The ideal customer for this type of product is someone who relies on consistent power for their work or entertainment. This includes home office workers, small business owners, gamers, and anyone with a valuable home theater setup. If your internet connection is vital, a UPS for your modem and router is a near necessity. It’s also for anyone living in an area prone to storms or with an unreliable power grid. However, a small standby UPS like this might not be suitable for those needing to power high-demand equipment like large servers, medical devices, or entire workstations for extended periods. For those users, a larger, more advanced line-interactive or online UPS would be a more appropriate investment. Similarly, if you only need surge protection without the battery backup, a high-quality surge protector would be a more economical choice.
Before investing, consider these crucial points in detail:
- Dimensions & Space: A UPS can be surprisingly dense and heavy due to its internal battery. Before buying, measure the space where you intend to place it—be it under a desk, in a media cabinet, or on a shelf. Consider ventilation as well, as these units can generate some heat. The compact tower form factor of many modern UPS systems makes them versatile, but always check the product’s footprint (D x W x H) to ensure a proper fit.
- Capacity/Performance: This is the most critical factor. Capacity is measured in Volt-Amps (VA) and Watts (W). The Watt rating is the more important number, as it tells you the maximum actual power the UPS can supply. Add up the wattage of all the devices you plan to connect to the battery-backed outlets (you can usually find this on the device’s power brick or in its manual) and ensure the total is well below the UPS’s Watt rating, ideally no more than 75% of its capacity, to allow for headroom.
- Materials & Durability: Most consumer-grade UPS units have a plastic enclosure, which is perfectly adequate for home use. However, some models, including the one we’re reviewing today, feature a sturdier metal housing. This can offer better heat dissipation and a more robust feel, suggesting a higher level of internal build quality that can withstand the rigors of a busy office environment.
- Ease of Use & Maintenance: A good UPS should be largely a “set it and forget it” device. Look for features like a clear LCD screen that provides at-a-glance status updates on load, battery level, and input voltage. Also consider the battery’s expected lifespan (typically 3-5 years) and whether it is user-replaceable. Included software for automated shutdown is a major bonus, especially for unattended computers.
Keeping these factors in mind, the Liebert PST5 660VA UPS Battery Backup stands out in several areas. You can explore its detailed specifications here.
While the Liebert PST5 660VA UPS Battery Backup is an excellent choice, it’s always wise to see how it stacks up against the competition. For a broader look at all the top models, we highly recommend checking out our complete, in-depth guide:
- Uninterruptible power supply (UPS) with 600VA / 330W battery backup power
- 1500VA/1000W PFC Sine Wave Battery Backup Uninterruptible Power Supply (UPS) System designed to support active PFC and conventional power supplies; Safeguards computers, workstations, network devices,...
- 1500VA/900W Intelligent LCD Battery Backup Uninterruptible Power Supply (UPS) System uses simulated sine wave output to safeguard workstations, networking devices, and home entertainment equipment
First Impressions and Key Features of the Liebert PST5 660VA UPS Battery Backup
Upon unboxing the Liebert PST5 660VA UPS Battery Backup, the first thing that struck me was its density. For a unit with such a small footprint, it has a surprising heft, a quality I attribute to its lead-acid battery and sturdy metal enclosure. This isn’t a flimsy plastic box; it feels like a serious piece of equipment, a nod to Liebert’s (now Vertiv) heritage in the commercial and industrial power space. The design is utilitarian and compact—a simple black tower that can sit unobtrusively on or under a desk. It even features keyhole slots on the back for wall mounting, a thoughtful touch for those with limited floor space.
Included in the box are the unit itself, a 6.5 ft USB Type-A to Type-B cable for connecting to a computer, and a quick start guide. Setup is foolproof: you simply plug it in and press the power button. The front-facing LCD screen immediately comes to life, providing a clear, backlit readout of the input voltage, output voltage, and load capacity. This screen is a significant upgrade over the simple LED indicator lights found on many competing budget models. The eight outlets on the back are clearly delineated: four are for battery backup and surge protection, while the other four are for surge protection only. Two of these are widely spaced, which is crucial for accommodating bulky “wall wart” power adapters without blocking adjacent outlets.
Advantages
- Excellent brand reputation with a robust 3-year warranty that includes the battery.
- Compact, space-saving tower design with a durable metal enclosure.
- Clear and informative LCD screen provides real-time status updates.
- Includes data line (RJ45/RJ11) surge protection.
- Energy Star certified for efficient operation.
Drawbacks
- Lacks Automatic Voltage Regulation (AVR), making it less suitable for sensitive electronics.
- The audible alarm during a power outage is extremely loud and cannot be muted via software or a button.
Putting the Liebert PST5 660VA to the Test: Real-World Scenarios
A UPS can look great on paper, but its true value is only revealed when the power goes out. We put the Liebert PST5 660VA UPS Battery Backup through a series of tests in a typical home office environment to see how it performs under pressure, from its core function of providing emergency power to its day-to-day usability.
Core Functionality: The Safe Shutdown Bridge
The primary purpose of a UPS in this class isn’t to let you work through a blackout for hours, but to provide a “safe shutdown bridge”—a calm, controlled window of time to save your files and properly power down your equipment. To test this, we connected a standard home networking setup: a cable modem, a Wi-Fi router, and a 2-bay Network Attached Storage (NAS) device. This entire load registered at just under 50 watts, barely making a dent in the UPS’s 400W capacity.
We then simulated a power outage by unplugging the UPS from the wall. The switchover to battery power was instantaneous. The connected devices didn’t so much as flicker; the internet connection remained stable, and the NAS continued its operations without interruption. This is the ideal scenario and where the Liebert PST5 660VA UPS Battery Backup truly shines. As one experienced IT technician noted in user feedback, this is precisely what a UPS is for: preventing a hard crash. For low-power, critical infrastructure like networking gear, this unit is a fantastic and reliable solution. Based on the load, the LCD estimated a runtime of over 30 minutes, more than enough time to wait out a brief outage or shut things down gracefully in a longer one. This performance makes it a highly compelling choice for anyone tired of their Wi-Fi rebooting during momentary power blips.
The Standby Switchover: A Tale of Two Sensitivities
This is where we must discuss a critical technical detail: the Liebert PST5 660VA UPS Battery Backup is a “standby” UPS. This means that under normal conditions, power passes directly from the wall to your devices, and the battery only kicks in when a problem is detected. This is different from more expensive “line-interactive” models, which feature Automatic Voltage Regulation (AVR). AVR constantly monitors and corrects minor voltage fluctuations without switching to the battery.
The absence of AVR on this model has real-world consequences. We tested this by connecting a more sensitive device—a 3D printer. When we simulated an outage, there was a momentary but perceptible delay in the switchover. The printer’s lights flickered, and it rebooted, losing the progress on its print job. Several user reports confirm this behavior, with some noting that security cameras reset or LED lights flicker during the transition. This is not a defect; it’s a characteristic of standby topology. For a desktop PC, a monitor, or networking gear, this micro-second delay is irrelevant. But for equipment that is highly sensitive to power interruptions, the lack of AVR means this UPS may not provide truly “uninterruptible” power. If you plan to protect such devices, you should invest in a line-interactive model. For those looking for a simple, reliable backup for their core electronics, however, this unit’s performance is more than adequate.
The User Experience: Display, Software, and That Infamous Beep
Living with a UPS day-to-day involves more than just its emergency performance. The LCD screen on the Liebert PST5 660VA UPS Battery Backup is a standout feature in its price class. It clearly displays input and output voltage, load percentage, and remaining battery, taking the guesswork out of its status. It’s a significant improvement over vague blinking lights. We also tested the free downloadable Vertiv Power Assist software. On a Windows PC, it installed flawlessly and provided a clean interface for monitoring the UPS and configuring an automatic, unattended shutdown if the power is out for a specified duration.
However, we must address the elephant in the room: the alarm. When the UPS switches to battery power, it emits a series of loud, sharp, and incessant beeps. This is a common feature on all UPS systems, designed to alert you to a power failure. The critical flaw here, echoed loudly in countless user reviews, is that there is no way to disable or mute this alarm. There is no physical button and no option in the software. While it serves its purpose, in a home office or living room, the noise can be intensely distracting and frustrating, especially during a short outage where you just want to keep working quietly. Some tech-savvy users have resorted to physically desoldering and removing the internal speaker, but this is a drastic measure that voids the warranty and is not recommended for the average user. This single design choice is, without a doubt, the product’s most significant drawback.
What Other Users Are Saying
After our own extensive testing, we delved into feedback from a wide range of users to see how their experiences aligned with ours. The consensus largely confirms our findings, painting a picture of a capable but flawed device.
On the positive side, many users praise the Liebert PST5 660VA UPS Battery Backup for its reliability with low-power devices. One user happily reported that it kept their “Verizon FIOS Optical Network Terminal & Router, 8 port network switch, and 2-bay NAS” running without a hitch during an outage. Another purchased it specifically for their entertainment center, noting that during two subsequent storms, their “TV stayed on without a glitch, streaming didn’t miss a second.” These comments highlight the unit’s success in its intended role. The compact size and solid build quality are also frequently mentioned as major pros.
However, the negative feedback is just as consistent. The most common and passionate complaint is about the non-mutable beeping alarm. Users describe it as “making me crazy” and “so loud and sharp.” The other major point of criticism stems from its lack of AVR. A user trying to power a 3D printer noted that it “powered off and back on” during the switchover, defeating the purpose. Another found that their security camera would reset, stating, “voltage stability isn’t there when switching.” These experiences are crucial for potential buyers to understand the limitations of a standby UPS.
How the Liebert PST5 660VA UPS Battery Backup Compares to the Alternatives
No product exists in a vacuum. To give you the full picture, we’ve compared the Liebert PST5 660VA UPS Battery Backup against three popular competitors, each offering a different set of features for different user needs.
1. Tripp Lite 750VA UPS Battery Backup
- MINI UPS BATTERY BACKUP: 750VA UPS provides 12-outlets total. Six outlets provide both battery backup and surge protection, and six outlets provide only surge protection. Features Pure Sine Wave in AC...
- AUTOMATIC VOLTAGE REGULATION: AVR UPS protects your sensitive tech equipment and extends the life of the UPS battery by correcting minor power flucuations, all without switching to battery power....
- HOME & OFFICE UPS: Provides 5ft power cord & bottom mounting tabs for wall-mount installation. Internal battery is easy replaceable with Tripp Lite's RBC51 cartridge. UPS filters out disruptive EMI/...
The Tripp Lite AVR750U is a direct and compelling competitor. Its main advantage is the inclusion of Automatic Voltage Regulation (AVR), which directly addresses the biggest technical shortcoming of the Liebert PST5. This means the Tripp Lite can correct brownouts and over-voltages without ever switching to its battery, providing cleaner power and a truly seamless experience for sensitive electronics. It also offers a generous 12 outlets, four more than the Liebert. For users who have experienced flickering or device resets with standby UPS units, or who live in an area with unstable power, the Tripp Lite is likely the superior choice, often for a very similar price.
2. CyberPower CP1500PFCLCD UPS 1500VA Battery Backup
- 1500VA/1000W PFC Sine Wave Battery Backup Uninterruptible Power Supply (UPS) System designed to support active PFC and conventional power supplies; Safeguards computers, workstations, network devices,...
- 12 NEMA 5-15R OUTLETS: Six battery backup & surge protected outlets, six surge protected outlets; INPUT: NEMA 5-15P right angle, 45 degree offset plug with five foot power cord; 2 USB charge ports (1...
- MULTIFUNCTION, COLOR LCD PANEL: Displays immediate, detailed information on battery and power conditions; Color display alerts users to potential issues before they can affect critical equipment and...
The CyberPower CP1500PFCLCD represents a significant step up in both performance and price. With a massive 1500VA/1000W capacity, it’s designed for power-hungry applications like high-end gaming PCs, workstations, or multiple-monitor setups. Its key features are its pure sine wave output on battery, which is essential for sensitive modern power supplies (PFC), and its line-interactive topology with AVR. This isn’t a direct competitor to the Liebert PST5; it’s in a different league. If you’re protecting equipment worth thousands of dollars or a computer that is your livelihood, the extra investment for the CyberPower is not just recommended, it’s essential.
3. Liebert PSA5-700MT120 UPS 700VA Battery Backup
- SURGE PROTECTION AND BATTERY BACKUP: The 1000VA/600W UPS has AVR to extend battery life and USB communications for notifications and controlled shutdown with free software download
- LINE-INTERACTIVE: Conditioning with automatic voltage regulation (AVR) to correct most disturbances without using battery power, providing conditioned power to equipment and extending battery life
- OUTLETS: Ten outlets, with five surge-only protected outlets and five battery and surge-protected outlets; USB charging port keeps personal electronics charged and available
For those who are loyal to the Vertiv/Liebert brand but need more features than the PST5 offers, the PSA5-700MT120 is the logical next step. This model is line-interactive, meaning it includes the crucial AVR technology missing from the PST5. It provides a slightly higher capacity (700VA/420W), more outlets (10 total), and adds two convenient USB charging ports on the front. This makes it a more versatile and robust solution for protecting a full workstation or sensitive home theater equipment, effectively bridging the gap between the budget-friendly PST5 and more premium models on the market.
Our Final Verdict on the Liebert PST5 660VA UPS Battery Backup
After rigorous testing and careful consideration, our verdict on the Liebert PST5 660VA UPS Battery Backup is a conditional recommendation. It is a well-built, compact, and reliable unit from a top-tier brand in the power protection industry. For its intended purpose—providing a safe shutdown bridge for non-sensitive, low-power electronics like modems, routers, and basic home computers—it performs admirably. The clear LCD screen and 3-year warranty are excellent features at this price point.
However, its two major flaws are impossible to ignore. The lack of Automatic Voltage Regulation (AVR) makes it a poor choice for sensitive equipment that can’t tolerate even a millisecond of power interruption. More universally, the aggressively loud and non-mutable alarm is a significant design oversight that can make a simple power flicker an infuriating experience.
Who should buy it? If you need an affordable, no-frills UPS to keep your internet connection alive or to give you time to save a document on your PC during a power blip, and you’re not bothered by a loud alarm, this is a solid value. For everyone else, especially those with sensitive electronics or a low tolerance for noise, we strongly recommend spending a little more on a line-interactive model with AVR and a mutable alarm.
If you’ve decided the Liebert PST5 660VA UPS Battery Backup is the right fit for your needs, you can check its current price and purchase it here.
Last update on 2025-10-21 / Affiliate links / Images from Amazon Product Advertising API