What, Exactly, is a Computer Battery Backup and Which One is Best?

A computer battery backup is a type of standby uninterruptible power supply (UPS) with a built-in surge suppressor, most often used for protecting desktop computers. More than 99 percent of the time, the battery backup is switched to a mode whereby the current is flowing through a surge suppressor and a filter en route to the destination computer. When the primary source of the current fails, a transfer switch automatically changes the primary source so that the battery supplies power through an inverter. Standby computer battery backup products are highly efficient and priced to be the best value for personal computers. Without such a means of protection from power interruptions, devastating damage can happen to stored information and computer equipment.

Some battery backup products have built-in filter and surge circuitry, which means they monitor the line and filter out spikes and surges. Also known as impulsive transients, spikes and surges can delete or corrupt data and physically damage equipment. Lightning causes the most severe variety of power surges, either through direct strikes or by striking adjacent conductive structures.

Although budget-priced battery backups are no substitute for a line conditioner, they do help to mitigate problems associated with voltage fluctuations, especially sags or undervoltage (also known as brownouts). A UPS that uses its inverter to adjust undervoltage without accessing the power supply will extend the life of its batteries. In order to protect against power problems such as swell (overvoltage), waveform distortion and frequency variations, a line conditioner is indicated, not a battery backup.

Battery backups usually divide the available outlets between “surge only” and “battery backup and surge protected.” They also usually provide a surge-protected data line that protects against surges and spikes that might happen to travel over an analog telephone line. Products based on batteries are useful for protecting not just computers, but any high-tech component that could be damaged because of improper shutdown due to brownouts and blackouts. Printers should not be plugged into a battery-based backup because it is not economical to do so. Printers should be plugged into the “surge only” outlets because they are not damaged as a result of a sudden loss of power. If a printer is plugged into the “battery backup and surge protected” outlet when the power cuts off, the UPS might drain itself before the computer, its main concern, has a chance to gracefully power down.

Even entry-level battery backups provide visual and audible alarms based on various states of alert. They also include automatic shutdown software that controls the connected microcomputer via USB port so that if the user happens to be away from the computer when the power fails, the system takes over and initiates safe shutdown procedures before the battery drains.

If you would like to examine specific examples of good products in this category, we invite you to read our reviews of the APC Back-UPS 450, the CyberPower CP425SLG and the Tripp Lite INTERNET350U. At TopTenREVIEWS We Do the Research So You Don’t Have To.™