Tripp Lite AVR900U UPS: This uninterruptible power supply has the wrong set of features

It’s a quality product, but not the right choice for computers or home network gear.

- GLENN FLEISHMAN

The 12-outlet Tripp Lite AVR900U is the wrong intersection of perfectly fine separate features in an otherwise well-made model. Its reasonable battery size could support a tricked-out computer system with multiple displays and peripherals for a few to several minutes during a power outage. The line-interactive approach incorporated in its design provides fast power switchover (as quick as a few milliseconds), along with constant power conditioning to correct for minor fluctuations without wearing out the internal battery.

On the other hand, the AVR900U relies on simulated power switching instead of a “pure” sine wave. That means it’s not the right choice for computers with active power factor correction (PFC). A simulated, or stepped, sine wave fed into an active PFC power supply can cause a high-pitched whine and prematurely wear its components or even cause it to fail.

Active PFC power supplies are more efficient than previous designs, and also allow voltage adaptive for worldwide sales. But they’re finicky about the smoothness of the alternating current fed into them, and it’s not worth the price of repairing your computer rather than buying a better-suited UPS with a pure sine-wave output that’s as smooth as utility power.

For about $40 more, you can instead purchase the CyberPower CP850PFCLCD (fave.co/3ClGhCq), a line-interactive UPS that also has a pure sine-wave output and similar power capacity. (We reviewed the slightly higher-capacity CyberPower CP1000PFCLCD [fave.co/2WEYXfR], which is in same series of UPS models.)