The CyberPower CP425SLG is the TopTenREVIEWS Silver Award winner in our battery backup review. The top two products are comparable in almost every way, except that the Gold winner has a slightly higher output capacity and the CyberPower has better surge suppression. When you are considering product specifications, backup power trumps surge suppression because an uninterruptible power supply (UPS) can always be plugged into a dedicated surge suppressor if the battery backup surge suppression is on the light side. All of the products in our review include three-year warranties. So if they ever sacrifice themselves to spikes that exceed the product ratings, the vendors will replace them.
Although surge suppression is nice to have in a battery backup, it does not protect against blackouts and brownouts, which can cause loss of data or damage to hardware components such as hard drives, network cards, sound cards and video cards. A battery backup stands by waiting for the power to fail as a result of overloaded electricity mains, short circuits, faults at power stations or damage to power lines. When the lights go out, within milliseconds the battery backup automatically switches to an AC/DC inverter to feed battery power to the microcomputer while the battery backup takes control via a USB connection to save open files and gracefully shut the system down before the battery drains. The battery backup’s output capacity determines how long it can keep the host computer up and running to ensure a safe shutdown. The CyberPower CP425SLG is preferable to our lower-ranked product in four ways: it has a higher output capacity, better surge protection, more receptacles and a lifetime data recovery warranty.
The CyberPower CPS425SLG can maintain a full power load to a typical PC for a couple of minutes, just long enough for its PowerPanel Personal Edition UPS Management Software to save open files, place the PC in hibernation mode and gently shut down. Macintosh users can configure options native to the Mac OS to accomplish the same functionality. And third-party utilities are available to support automatic shutdown of Linux machines. This uninterruptible power supply signals with an audible alarm whenever it switches to battery power, or when the battery is overloaded or running low. After the battery is completely drained, it takes eight hours to recharge. The battery has an approximate lifespan of between three and five years (depending on how many times it has discharged and recharged), and it can be replaced by the user.
The CyberPower CP425SLG has an output capacity of 425 volt-amps and 255 watts, slightly more than enough for a typical microcomputer, but not quite enough for even a modest gaming PC. You may notice that the output in watts is 60 percent of the output in volt-amps, which is a deviation from the typical electrical engineering formula, which states that watts = volts x amps. While electrical devices such as incandescent light bulbs have a standard watt to volt-amps relationship where watts = volts x amps, this formula does not apply to computers. For computers, volt-amps are the method of correctly sizing the circuit breakers and wiring, and watts measure the power that a subscriber purchases from the utility company. Because there are so many variables that determine the amount of power that any particular computer requires, CyberPower Systems recommends that the CyberPower CP425SLG battery backup should not be connected to computers that require more than 80 percent of the backup power’s maximum output rating.
Although output capacity is of primary importance when considering battery backup products, all of the products in our review also include modest spike-suppression abilities. This backup power’s AC surge protection rating is the best in our review: it can absorb 890 joules without failure. In order to prevent telephone line noise or other audio humming, there are shields to protect against electromagnetic interference (EMI) and radio frequency interference (RFI). There is also a surge-protected data line. Eight power receptacles are divided into four that offer surge protection only and four that offer battery backup and surge protection. Four of the eight receptacles are spaced widely enough to accommodate large, transformer-based plugs. In order to provide maximum power in support of computer shutdown, printers should be attached to the surge-protection-only receptacles because they are not damaged during blackouts. In case of a power overload, there is a resettable circuit breaker. The unit is designed to be mounted horizontally or vertically in a cabinet or on a wall.
The warranty for the CyberPower CPS425SLG battery backup matches that of our top-ranked product in every detail: free technical support, a three-year hardware warranty, a lifetime data recovery warranty and $75,000 worth of connected equipment insurance. Warranties are not transferable to users other than the original purchaser. On four separate occasions, we tested CyberPower Systems technical support staff for responsiveness, knowledge and professionalism, and encountered no disappointments.
The CyberPower CP425SLG battery backup gives our Gold winner a good run for its money. The CyberPower’s output capacity is almost a match, and it has more than twice the AC surge protection. Their warranties and technical support policies are identical. Both of them have sufficiently low levels of toxic materials to conform to the European Union’s Restriction of Hazardous Substances Directive (RoHS).
