The UPS unit I have now, an APC brand, is ok but the battery is nowhere close to being able to power my computer when the power is lost. This is lousy but it still protects the computer from being damaged during a power surge, so I'm grateful to have it. You can hear the breaker when there is a spike, and then it resets after the power levels return to normal. While it does this, nothing happens with the computer even if it's running.