The CyberPower ST425 is a compact standby uninterruptible power supply (UPS) designed to keep essential low-power electronics running during brief power outages and to protect them from surges. It offers 425VA/260W of battery backup, making it suitable for home office and entertainment setups.
This review covers the ST425's features, performance, pricing, and user feedback to help you decide if it fits your needs.
What the CyberPower ST425 Offers
The ST425 is a standby (offline) UPS, meaning it switches to battery power only when it detects a complete power failure. Under normal conditions, your devices run directly on utility power.
Key specifications include:
- Capacity: 425VA / 260W
- Outlets: 8 total (4 battery backup + surge protection, 4 surge-only)
- Waveform: Simulated sine wave
- Topology: Standby
- Battery: Sealed lead-acid, user-replaceable (per some sources; others say non-user-replaceable)
- Warranty: 3 years, including battery
- Connected Equipment Guarantee: Up to $75,000
- Dimensions: 3.2 x 8.3 x 4.5 inches
- Weight: 3.8 pounds
- Cord Length: 5 feet
The unit uses GreenPower UPS technology for high efficiency, reducing power consumption. It also features transformer-spaced outlets to accommodate bulky power adapters.
Performance and Runtime
The ST425 is designed for low-wattage devices such as routers, modems, network switches, and small desktop computers. Runtime varies with load:
- At a 40W load (typical router + modem), runtime can exceed 30 minutes.
- At half load (130W), expect 16–20 minutes.
- At full load (260W), runtime is roughly 90 seconds—just enough for a safe shutdown.
It's important to note that the 260W ceiling limits what you can connect. Gaming PCs or high-draw devices are not supported. The simulated sine wave output is compatible with most consumer electronics but may cause issues with active PFC power supplies found in some modern desktops.
Pricing and Value
The CyberPower ST425 typically sells for around $60, placing it at the low end of the UPS market. For the price, it offers a respectable feature set: eight outlets, a 3-year warranty (including battery), and a $75,000 connected equipment guarantee.
However, competing models like the APC Back-UPS BE425M offer similar specs, though with fewer outlets and no GreenPower efficiency. Higher-capacity CyberPower units like the CP1500PFCLCD provide more power and pure sine wave output but cost significantly more.
User Feedback
User reviews are mixed but generally positive. Many appreciate the compact design, easy setup, and quiet operation. The surge protection and battery backup for networking gear are frequently praised.
Common complaints include:
- Short runtime at higher loads.
- Audible beeping during outages that some find annoying and difficult to silence.
- Battery longevity—some users report failures after 2–3 years, though the warranty covers replacement.
- Lack of USB data port and software support for automatic shutdown (some sources mention PowerPanel support, but others indicate it's absent).
Pros and Cons
| Pros | Cons |
|---|---|
| Affordable price (~$60) | Limited to 260W, not for high-power devices |
| 8 outlets (4 battery, 4 surge) | Simulated sine wave may not suit all electronics |
| Compact and quiet | No USB data port for auto shutdown (per some sources) |
| 3-year warranty including battery | Audible alarms can't be silenced |
| $75,000 equipment guarantee | Short runtime at full load |
Summary
The CyberPower ST425 is a solid entry-level UPS for protecting low-power essentials like routers, modems, and small office equipment during brief outages. Its compact size, affordable price, and included warranty make it a good value for basic backup needs.
However, it's not suitable for gaming PCs or high-draw devices, and its simulated sine wave output may limit compatibility. If you need longer runtime or pure sine wave output, consider a higher-capacity model. For its intended use case—keeping your network alive and giving you time to save work—the ST425 delivers reliable performance at a budget-friendly price.
